Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.
By: JeffMasters, 3:18 PM GMT on May 30, 2014
The 2014 Atlantic hurricane season is officially underway on Sunday, June 1. What will this year's hurricane season bring? My top six questions for the coming season:
1) When will the first "Invest", tropical depression, and named storm of the 2014 Atlantic hurricane season form? We have a chance of all three of these events occurring in the Gulf of Mexico during the first week of hurricane season, though the models are currently hazy about this. An area of disturbed weather in the Eastern Pacific located a few hundred miles south of Southeast Mexico is forecast to move slowly northwards towards the Gulf of Mexico Sunday through Tuesday. In their 8 am EDT Friday Tropical Weather Outlook, NHC gave this system a 50% chance of developing into a tropical depression or tropical storm by Wednesday. The 06Z Friday run of the GFS model predicts that this disturbance will make landfall in Southeast Mexico on Tuesday, then spread moisture northwards over the Gulf of Mexico late in the week. The model predicts that wind shear will be light to moderate over the Gulf late in the week, potentially allowing the disturbance to spin up into a tropical depression. The 00Z Friday run of the European model has a different solution, predicting that the Eastern Pacific tropical disturbance will remain south of Mexico through Friday. However, the model suggests that moisture streaming into the Gulf of Mexico late in the week will be capable of spawning an area of low pressure with the potential to develop in the Southern Gulf of Mexico's Bay of Campeche. In any case, residents of Southeast Mexico and Western Guatemala appear at risk to undergo a multi-day period of very heavy rainfall capable of causing flash flooding and dangerous mudslides beginning as early as Monday. This disturbance may cross over Mexico and into the Gulf of Mexico and create the Atlantic's first "Invest" with the potential to develop late in the week, sometime June 5 - 7.
Figure 1. Satellite image taken at 7:45 am EDT Friday May 30, 2014, showing an area of disturbed weather a few hundred miles south of Southeast Mexico. Will this disturbance cross over into the Gulf of Mexico and create the Atlantic's first "Invest" of 2014 late in the week? Image credit: NASA/GSFC.
2) All of the major seasonal hurricane forecasts are calling for a below-average to near-average season, with 9 - 12 named storms, 3 - 6 hurricanes, and 1 - 2 major hurricanes. Hurricane seasons during the active hurricane period 1995 - 2013 averaged 15 named storms, 8 hurricanes, and 4 major hurricanes. Will an El Niño event indeed arrive, bringing reduced Atlantic hurricane activity, allowing the pre-season predictions to redeem themselves after a huge forecast bust in 2013?
3) How will the steering current pattern evolve? El Niño years tend to feature more storms that recurve out to sea and miss land; will this be the case in 2014?
4) Will the U.S. break its 2006 - 2013 eight-year run without a major hurricane landfall, the longest such streak since 1861 - 1868?
5) Will the 170,000 people still homeless and living in makeshift shelters in Haiti in the wake of the January 2010 earthquake dodge a major tropical cyclone flooding disaster for the fifth consecutive hurricane season?
6) Will the new experimental National Hurricane Center products be useful and popular? I am most looking forward to the Potential Storm Surge Flooding Maps, interactive zoomable maps that will show where the storm surge has a 10% chance of inundating the coast at 3, 6, and 9 feet above ground level. The new NHC blog (first post: May 29, 2014) and 5-day graphical weather outlook (begins July 1) should also be of interest.
Figure 2. Sample experimental NHC Potential Storm Surge Flooding Map for the Texas coast for a fictional hurricane (not Hurricane Ike), generated using using NOAA's Probabilistic Hurricane Storm Surge (P-Surge 2.0) model. P-Surge 2.0 uses multiple runs of the NWS Sea, Lake, and Overland Surges from Hurricanes (SLOSH) model to create an ensemble of possible inundations, by varying the hurricane's landfall location, intensity, size, forward speed, and angle of approach to the coast. The image shows where the storm surge has a 10% chance of inundating the coast at 3, 6, and 9 feet above ground level. The model does not take into account wave action, freshwater flooding from rainfall, and breaching or overtopping of levees.
Cosmos takes on Climate Change
The groundbreaking Fox and National Geographic Channel series Cosmos, hosted by Neil DeGrasse Tyson, has been attracting more than 3 million viewers every Sunday night--an impressive tally for a science-based show. Cosmos has been unafraid to confront controversy, taking on creationism and industry-funded science denial, for example. This Sunday, June 1, at 9 pm EDT/8 pm CDT, Cosmos takes on climate science deniers with a full 1-hour episode devoted to climate change. According to Chris Mooney of motherjones.com, who had a chance to preview the episode, "it contains some powerful refutations of a number of global warming denier talking points, as well as some ingenious sequences that explain the planetary-scale significance of climate change. It also contains some in-situ reporting on the impacts of climate change, straight from the imperiled Arctic." I'm looking forward to seeing the legacy of Carl Sagan continue this Sunday night. For those who miss it on Sunday, Cosmos also airs Monday, June 2nd at 9 pm EDT on National Geographic Channel, with additional footage.
Video 1. Neil DeGrasse Tyson uses the analogy of walking a dog on the beach to explain the difference between climate and weather, showing that no matter how cold your winter may have been, that's no argument against global warming. Tyson travels to the Arctic to explain global warming and its effect on thawing permafrost in this Sunday's Cosmos episode (9pm EDT/8 CDT.)
Have a great weekend, everyone, and I'll be back Monday with a new post--earlier if the disturbance in the EPac looks like a significant threat.
Updated: 4:41 PM GMT on May 30, 2014
By: JeffMasters, 2:46 PM GMT on May 28, 2014
Over the past 30 years, the location where tropical cyclones reach their maximum intensity has been shifting toward the poles in both the northern and southern hemispheres at a rate of about 35 miles (1/2° of latitude) per decade, according to a May 2014 study published in the journal Nature. Tropical cyclones include tropical storms, hurricanes, and typhoons. "Historical intensity estimates can be very inconsistent over time, but the location where a tropical cyclone reaches its maximum intensity is a more reliable value and less likely to be influenced by data discrepancies or uncertainties," said NOAA/University of Wisconsin lead author Jim Kossin in a NOAA press release. The researchers used data only from 1982 - 2012, the era when accurate global satellite data makes a full study of tropical cyclone intensities most feasible.
Figure 1. MODIS image of Hurricane Earl taken at 2 pm EDT September 1, 2010, by NASA's Aqua satellite. Earl's 140 mph Category 4 winds when it was off the coast of Northern Florida on September 2, 2010, made it the third strongest Atlantic hurricane on record so far north in U.S. coastal waters. Only Hurricane Esther of 1961 and Hurricane Connie of 1955 made it farther north in U.S. coastal waters at a higher strength. Both storms had winds 5 mph stronger than Earl--145 mph. One other Atlantic hurricane was stronger than Esther and Connie at a more northerly latitude--the second storm of 1922, which had winds of 150 mph. However, this hurricane was far out at sea, north of Bermuda. Image credit: NASA.
Causes of the poleward shift
The poleward shift in tropical cyclones was likely due to observed changes in vertical wind shear and tropical cyclone potential intensity over the past 30 years, which changed the regions most favorable for tropical cyclone development, the researchers said. Wind shear has been decreasing closer to the poles, and the potential intensity has been increasing (the potential intensity of a tropical cyclone depends upon the sea surface temperature underneath the storm and the amount of atmospheric instability, with warm air near the surface and cold air aloft giving higher instability and potential intensity.) Interestingly, these shifts were primarily observed in the Western North Pacific Ocean and the Southern Hemisphere's ocean areas. The North Atlantic Ocean and Eastern North Pacific exhibited only small poleward trends; the North Indian Ocean did not show any poleward trends. The researchers proposed that the poleward migration of tropical cyclones is linked to the observed poleward migration of the tropics over the past 30 years, since both have migrated similar distances. The causes of the expansion of the tropics are not certain, but a 2013 study led by Christopher Lucas of the Centre for Australian Weather and Climate Research/Bureau of Meteorology, The expanding tropics: a critical assessment of the observational and modeling studies, found that including increasing greenhouses gases, stratospheric ozone depletion, and pollution in the form of small particles were likely to blame, with no single factor by itself explaining the full expansion.
As tropical cyclones move poleward, some regions closer to the Equator may experience reduced risk of damage, while coastal populations and infrastructure poleward of the tropics may experience increased risk. With their devastating winds and flooding, tropical cyclones can especially endanger coastal cities not adequately prepared for them. Additionally, regions in the tropics that depend on cyclones' rainfall to help replenish water resources may be at risk for lower water availability as the storms migrate away from them.
Kossin, J.P, K.A. Emanual, and G.A. Vecchi, 2014, The poleward migration of the location of tropical cyclone maximum intensity, Nature 509, 349–352 (15 May 2014) doi:10.1038/nature13278
Dr. Kossin used a similar data set in a 2013 paper, Trend Analysis with a New Global Record of Tropical Cyclone Intensity, to show that the strongest Atlantic hurricanes that reached a peak strength of at least 112 mph (Category 3) increased in strength by 18 mph (8 m/s) per decade between 1982 - 2009. Globally, the increase in strength of the strongest tropical cyclones was much smaller, about 2 mph (1 m/s) per decade.
Dr. Kossin also published a 2008 paper in Geophysical Research Letters, "Is the North Atlantic hurricane season getting longer?" He concluded that yes, there is a "apparent tendency toward more common early- and late-season storms that correlates with warming Sea Surface Temperature but the uncertainty in these relationships is high". See my blog post on this paper here.
What the official climate assessments say about climate change and hurricanes
The 2013 IPCC report gives “low confidence”--a 20% chance--that we have observed a human-caused increase in intense hurricanes in some parts of the world. This is a reduction in odds from the 2007 report, which said that it was more likely than not (greater than 50% chance.) The IPCC likely took note of a landmark 2010 review paper, "Tropical Cyclones and Climate Change", authored by ten top hurricane scientists, which concluded that the U.S. had not seen any long-term increase in landfalling tropical storms and hurricanes, and that "it remains uncertain whether past changes in tropical cyclone activity have exceeded the variability expected from natural causes." The 2013 IPCC report predicts that there is a greater than 50% chance (more likely than not) that we will see a human-caused increase in intense hurricanes by 2100 in some regions; this is also a reduction from the 2007 report, which said this would be likely (66% chance or higher.)
The May 2014 United States National Climate Assessment found that “The intensity, frequency, and duration of North Atlantic hurricanes, as well as the frequency of the strongest (Category 4 and 5) hurricanes, have all increased since the early 1980s. The relative contributions of human and natural causes to these increases are still uncertain. Hurricane-associated storm intensity and rainfall rates are projected to increase as the climate continues to warm.”
By: JeffMasters, 2:42 PM GMT on May 27, 2014
The Eastern Pacific's first named storm of 2014, Amanda, put on an impressive performance of rapid intensification over the Memorial Day weekend, becoming the strongest May Eastern Pacific hurricane ever recorded on Sunday. Amanda peaked as a top-end Category 4 hurricane with 155 mph winds at 15 UTC (10 am EST) May 25, beating the previous May record holder, Hurricane Adolph of 2001, which reached a peak intensity of 145 mph on May 29th of that year. The earliest Category 5 storm on record in the Eastern Pacific was Hurricane Ava of 1973, which peaked at 160 mph on June 6, 1973. All three years (2014, 2001, and 1973) had ocean temperatures that were unusually warm for May along the path of these intense hurricanes: at least 0.4°C above average.
Figure 1. Hurricane Amanda at approximately 18 UTC (1 pm EDT) on May 25, 2014. Amanda had just peaked as a top-end Category 4 hurricane with 155 mph winds three hours previous to this MODIS image, at 15 UTC (10 am EST) Sunday, May 25. Image credit: NASA Worldview.
Satellite loops show that Amanda has been holding its own against moderate wind shear, and is maintaining Category 3 status, with a solid area of heavy thunderstorms with cold cloud tops. Wind shear is moderate, 15 - 20 knots, and the SHIPS model shows that sea surface temperatures (SSTs) are a very warm 28 - 29°C, which is well above the typical 26°C threshold needed to maintain a tropical storm. These conditions should allow Amanda to remain a hurricane through Wednesday. By Thursday, Amanda is expected to encounter higher wind shear and cooler waters, which should weaken the storm. Amanda is expected to dissipate before reaching the coast of Mexico.
Atlantic hurricane season begins June 1
The Atlantic hurricane season starts next week, and the long-range GFS model continues to suggest that the Western Caribbean will be capable of brewing the season's first "Invest" during the first week of June. Residents of Cuba, Mexico's Yucatan Peninsula, the Cayman Islands, Jamaica, Honduras, and Nicaragua should anticipate the possibility of a multi-day period of disturbed weather with heavy rainfall beginning around June 2.
Updated: 3:04 PM GMT on May 27, 2014
By: JeffMasters, 3:26 PM GMT on May 23, 2014
The season's first named storm of 2014, Tropical Storm Amanda, has formed in the Eastern Pacific. Amanda is over 600 miles southeast of Manzanillo, Mexico, and is not a threat to any land areas. The arrival date of May 23 for season's first Eastern Pacific tropical storm is a bit early, compared to climatology. Usually, the first tropical storm of the season arrives on June 10, and the first hurricane on June 26. Last year, the season's first tropical storm, Alvin, formed on May 15, and the first hurricane, Barbara, occurred on May 29.
Figure 1. Friday morning satellite image of newly-born Tropical Storm Amanda.
Satellite loops show that Amanda has a moderately large area of heavy thunderstorms that are increasing in areal extent and intensity. WInd shear is low, 5 - 10 knots, and the SHIPS model shows that sea surface temperatures (SSTs) are a very warm 29°C, which is well above the typical 26°C threshold needed to maintain a tropical storm. All conditions appear in place to allow Amanda to intensify into a hurricane, and the official NHC forecast brings Amanda to Category 1 strength by Sunday. On Tuesday, Amanda is expected to turn to the north and encounter higher wind shear and cooler waters, which should weaken the storm.
Figure 2. The departure of sea surface temperature from average over the Eastern Pacific shows a large area of warmer than average water over the typical hurricane breeding grounds off the coast of Mexico. These warm waters will likely persist through the summer and into fall, due to a developing El Niño event, and promote a more active than usual Eastern Pacific hurricane season.
NOAA predicts an above-normal or near-normal Eastern Pacific hurricane season: 17 named storms
As is usually the case when an El Niño event is threatening, NOAA's pre-season prediction for the Eastern Pacific hurricane season, issued on May 22, is calling for an active season. NOAA expects there to be 14 - 20 named storms, 7 - 11 hurricanes, 3 - 6 major hurricanes, and an ACE index 95% - 160% of the median. The mid-point of these ranges gives us a forecast for 17 named storms, 9 hurricanes, and 4.5 major hurricanes, with an ACE index 127.5% of average. The 1981 - 2010 averages for the Eastern Pacific hurricane season are 15 named storms, 8 hurricanes, and 4 major hurricanes. The outlook calls for a 50% chance of an above-normal season, a 40% chance of a near-normal season, and a 10% chance of a below-normal season. El Niño decreases the vertical wind shear over the tropical Eastern Pacific, favoring the development of more and stronger tropical cyclones. Since 1995 the Eastern Pacific has been in an era of low activity for hurricanes, but this pattern is expected to be offset in 2014 by the impacts of El Niño.
Atlantic hurricane season begins June 1
The Atlantic hurricane season starts in just over a week, and the long-range GFS model continues to suggest that the Western Caribbean will be capable of brewing the season's first "Invest" during the first week of June. The Madden Julian Oscillation (MJO), a pattern of increased thunderstorm activity near the Equator that moves around the globe in 30 - 60 days, is currently weak, but the latest GFS forecast predicts that the MJO will strengthen slightly in early June, and might be in a position to increase thunderstorm activity over the Western Caribbean then. While long range 10 - 16 day forecasts are notoriously unreliable, early June is a common time of year for the Western Caribbean to see a tropical disturbance form. Residents of Cuba, the Cayman Islands, Jamaica, Honduras, and Nicaragua should anticipate the possibility of a multi-day period of disturbed weather with heavy rainfall beginning around June 1.
Have a great Memorial Day weekend, everyone!
By: JeffMasters, 4:46 PM GMT on May 22, 2014
The Atlantic hurricane season starts in just over a week, and long-range models are already pointing to the possibility that the Western Caribbean will be capable of brewing the season's first "Invest" during the first week of June. But so far, the major hurricane forecasting groups are not impressed with this season's potential to be an active one. They are calling for 2014 to be a below average to near-average year for the Atlantic. NOAA's prediction, issued this Thursday morning, forecasts a 50% chance of a below-normal season, a 40% chance of an near-normal season, and only a 10% chance of an above-normal season. They predict a 70% chance that there will be 8 - 13 named storms, 3 - 6 hurricanes, and 1 - 2 major hurricanes, with an Accumulated Cyclone Energy (ACE) 40% - 100% of the median. If we take the midpoint of these numbers, NOAA is calling for 10.5 named storms, 4.5 hurricanes, 1.5 major hurricanes, and an ACE index 70% of normal. This is below the 1981 - 2010 average of 12 named storms, 6 hurricanes, and 3 major hurricanes. Hurricane seasons during the active hurricane period 1995 - 2013 have averaged 15 named storms, 8 hurricanes, and 4 major hurricanes, with an ACE index 151% of the median.
NOAA cites three key factors influencing their forecast for a below-normal to near-normal hurricane season:
1) An El Niño event is predicted for the summer and fall, which is expected to bring strong wind shear-inducing upper-level winds over the Tropical Atlantic. Vertical wind shear during the past 30 days was stronger than average across much of the Main Development Region (MDR) for hurricanes, from the coast of Africa to the Caribbean. Sinking air at mid-and upper-levels was also stronger than average. The development of El Niño would mean a likely continuation of these non-conducive conditions, and both versions of NOAA's long-range CFS model are predicting enhanced vertical wind shear across the western MDR during August-September-October 2014. Strong vertical wind shear and sinking motion, linked to a rare jet stream pattern of record strength, were key suppressing factors during the unexpectedly quiet 2013 Atlantic hurricane season.
2) Sea Surface Temperatures (SSTs) are near average in the MDR. Many long-range dynamical computer forecast models are predicting that SSTs in the MDR will remain near- or below-average throughout the hurricane season.
3) We are in an active hurricane period that began in 1995, and this positive phase of the Atlantic Multi-decadal Oscillation (AMO) may act to keep hurricane activity higher than it would otherwise be.
Colorado State predicts a below-average hurricane season: 10 named storms
A below-average Atlantic hurricane season is on tap for 2014, according to the June 2 seasonal hurricane forecast by Dr. Phil Klotzbach and Dr. Bill Gray of Colorado State University (CSU). The CSU team is calling for 10 named storms, 4 hurricanes, and 1 intense hurricane, and an Accumulated Cyclone Energy (ACE) of 65, about 2/3 of average. The forecast calls for a below-average chance of a major hurricane hitting the U.S., both along the East Coast (22% chance, 31% chance is average) and the Gulf Coast (23% chance, 30% chance is average). The risk of a major hurricane in the Caribbean is also below average, at 32% (42% is average.)
Updated: 2:23 PM GMT on June 02, 2014
By: JeffMasters, 3:21 PM GMT on May 20, 2014
April 2014 tied with April 2010 as Earth's warmest April since records began in 1880, said NOAA's National Climatic Data Center (NCDC) today, making April the first month since November 2013 to set a global monthly temperature record. NASA rated April 2014 as the 2nd warmest April on record; global land temperatures were the 3rd warmest on record, as were global ocean temperatures. The year-to-date January - April period has been the 6th warmest on record for the globe. Global satellite-measured temperatures in April 2013 for the lowest 8 km of the atmosphere were 11th or 7th warmest in the 36-year record, according to Remote Sensing Systems and the University of Alabama Huntsville (UAH), respectively. Northern Hemisphere snow cover during April was the 6th lowest in the 48-year record. Wunderground's weather historian, Christopher C. Burt, has a comprehensive post on the notable weather events of April 2014 in his April 2014 Global Weather Extremes Summary.
Figure 1. Departure of temperature from average for April 2014, the warmest April for the globe since record keeping began in 1880. Much of central Siberia observed temperatures more than 9°F (5°C) above the 1981-2010 average. This region, along with parts of eastern Australia and scattered regions in every major ocean basin, were record warm. Many nations in Europe experienced a top-ten warmest April, including Spain (2nd), Germany (4th), United Kingdom (4th), Denmark (4th), Norway (7th), and Austria (10th.) Parts of southern and eastern Canada, the northern U.S., and southern Kazakhstan were cooler than average. No land areas were record cold. Image credit: National Climatic Data Center (NCDC) .
Three billion-dollar weather disasters in April 2014
Three billion-dollar weather-related disasters hit the Earth during April 2014, according to the April 2014 Catastrophe Report from insurance broker Aon Benfield:
Disaster 1. The Western U.S. drought of 2014 now has damages estimated at $4 billion. Most of these losses are in California, where the California Farm Water Coalition has cited agricultural damages of $3.6 billion. In this photo, we see one of the key water supply reservoirs for Central California, Lake Oroville, on January 20, 2014. Thanks to an unusually intense ridge of high pressure over Western North America, California endured its driest November - January period on record this past winter. Image credit: California Department of Water Resources.
Disaster 2. The U.S. tornado outbreak of April 27 - May 1 killed 39 and caused at least $2 billion in damage. Eleven tornadoes rated EF-3 or higher touched down, including two EF-4 tornadoes. in this photo we see tornado damage in Tupelo, Mississippi, from an EF-3 tornado that hit on April 28, 2014, killing one person. (J. Robert Senseman)
Disaster 3. Visible satellite image of Tropical Cyclone Ita taken at 04 UTC April 11, 2014. At the time, Ita was a Category 4 storm with 145 mph sustained winds. Ita ravaged agriculture in Queensland, Australia, resulting in $1 billion in damage. Image credit: NASA.
An El Niño Watch continues
April 2014 featured neutral El Niño conditions in the equatorial Eastern Pacific, but NOAA has issued an El Niño Watch for the summer and fall of 2014, giving a greater than 65% chance that an El Niño event will occur by the summer. I made a detailed post on El Niño on May 12.
Arctic sea ice falls to 5th lowest April extent on record
Arctic sea ice extent during April was 5th lowest in the 36-year satellite record, according to the National Snow and Ice Data Center (NSIDC). The winter maximum extent of Arctic sea ice came on March 21, and was the 5th lowest such peak on record. Temperatures over most of the Arctic Ocean were 1 - 3°C (2 - 5°F) above average during April.
I'll have a new post on Thursday by 1pm EDT, when NOAA's new Atlantic hurricane season forecast will be available.
By: JeffMasters, 3:19 PM GMT on May 19, 2014
Torrential rains on May 14 - 15 in Serbia and Bosnia-Herzegovina have caused extreme flooding that has killed at least 38 people, said Reuters today, with the death toll expected to rise once flooding recedes and areas cut off from help are reached. Extratropical Storm Yvette, a strong and slow-moving upper-level low pressure that cut off from the jet stream, lingered over the region for two days, pulling up copious amounts of moisture from the Mediterranean Sea and generating torrential rains. "In three days, as much rain fell as normally falls in three months," said Goran Mihajlovic, of Serbia's Meteorological Institute. "Statistically, such rainfall happens once in 100 years," he added. At least 500,000 of Bosnia's four million people have been evacuated or have left their homes. More than 100,000 buildings have been damaged or destroyed, and more than one million people are without clean water. The floods have been unearthing land mines and bombs left over from the 1992 - 1995 war, one of which showed up in this man's garden, as seen at 1:25 into the video.
The same high-amplitude jet stream pattern that contributed to the heavy rains over Bosnia and Serbia last week is now bringing record May heat to portions of Russia, Finland, and Estonia today. In St. Petersburg, Russia, the mercury climbed to 32.7°C (91°F) on Monday afternoon, beating the former May all-time record of 30.9°C set in 1958, according to weather records researcher Maximiliano Herrera.
Figure 1. Aerial view of the flooded area near the Bosnian town of Brcko along the river Sava, taken May 18, 2014. (AP Photo/Bosnia Army)
Figure 2. Though the heavy rains have ceased, many rivers in Serbia and Bosnia will continue rising this week, as rain-swollen tributaries pour into main rivers. The Sava River in Beograd (Belgrade), Serbia is forecast to continue rising through Friday, May 23, but is below the all-time flood height of 738 cm set on April 16, 2006. The Sava upstream from Belgrade at Sabac crested at an all-time record height on Sunday, May 18, 2014 (flood stage records go back to 1946.) There are concerns that the Sava River 18 miles downstream of Belgrade will overwhelm the flood defenses of Serbia's largest power plant, the coal-fired Nikola Tesla complex, which provides half of the nation's power. Image credit: Republic Hydrometeorological Service of Serbia.
Video 1. A landslide destroys a house in Bosnia in the wake of extreme flooding that hit the nation on May 15 - 16, 2014. At least 3,000 landslides were spawned by the torrential rains that hit Bosnia and Serbia. Thanks go to wunderground member barbamz for posting this video and the Sava River water level link in the comments section of my blog.
Updated: 6:34 PM GMT on May 19, 2014
By: JeffMasters, 2:13 PM GMT on May 16, 2014
More record May heat seared Southern California on Thursday, and fierce Santa Ana winds continued to fan nine wildfires in San Diego County. The fires had destroyed at least eight houses, an 18-unit condominium complex and two businesses and burned more than 15 square miles by Thursday evening, causing more than $20 million in damage. Los Angeles Airport hit 97° on Thursday, which is tied for the hottest May temperature on record, said the NWS in Los Angeles (note, though, that NOAA's Threaded Extremes website lists the all-time May record for LAX at 91°.) All-time record May heat was also recorded on Thursday at Santa Maria (105°.) In Downtown Los Angeles, the mercury hit 102° on Thursday, falling short of the all-time May record of 103° set on May 25, 1896. Temperatures is coastal Southern California are forecast to be 10 - 15° cooler on Friday than on Thursday, and the hot offshore Santa Ana winds will no longer be blowing. This should allow firefighters to gain the upper hand on most of the fires. A steady cool-down will occur over the weekend, with a moist onshore flow of air significantly reducing the fire danger.
Figure 1. A wildfire burns near a home on Wednesday, May 14, 2014, in San Marcos, Calif. Flames engulfed suburban homes and shot up along canyon ridges in one of the worst of several blazes that broke out Wednesday in Southern California during a second day of a sweltering heat wave. (AP Photo)
100% of California in severe to exceptional drought
Thursday's U.S. Drought Monitor report showed grim news for California: 100% of the state is now in severe or higher drought, up from 95% the previous week. Though just 25% of California is classified as being in the highest level of drought, "Exceptional", Erin McCarthy at the Wall Street Journal estimates that farms comprising 53% of California's $44.7 billion market value lie in the Exceptional drought area. During the most recent California rainy season, October 2013 through April 2014, the state received 10.44" of precipitation, which is just 51% of average for the period, and the third lowest such total on record. California typically receives less than 10% of its annual precipitation between May and September, and the coming hot and dry summer in combination with a severely depleted Sierra snowpack will cause a severe fire season and significant agricultural damages. The fifth and final snow survey of the season on May 1 found that the statewide snowpack’s water content--which normally provides about a third of the water for California’s farms and cities--was only 18% of average for the date. Already, the 2014 drought has cost the state at least $3.6 billion in agricultural damages, the California Farm Water Coalition estimates. CAL FIRE recently announced it had hired 125 additional firefighters to help address the increased fire threat due to drought conditions.
Figure 2. True-color MODIS satellite image of Extratropical Storm Yvette taken on Thursday afternoon, May 15, 2014. Image credit: NASA.
Extreme Flooding in Southeast Europe
In Southeastern Europe, torrential rains on May 14 - 15 in Serbia and Bosnia-Herzegovina have caused some of their worst flooding ever recorded, killing at least three people and leaving thousands homeless. Extratropical Storm Yvette, a strong and slow-moving upper-level low pressure that cut off from the jet stream, lingered over the region for two days, pulling up copious amounts of moisture from the Mediterranean Sea and generating torrential rains. Serbian Prime Minister Aleksandar Vucic declared a state of emergency in 18 towns and cities, including the capital, Belgrade. "This is the greatest flooding disaster ever. Not only in the past 100 years; this has never happened in Serbia's history," he told a news conference. "In three days, as much rain fell as normally falls in three months," said Goran Mihajlovic, of Serbia's Meteorological Institute. "Statistically, such rainfall happens once in 100 years," he added.
Video 1. A severed bridge floats down the Bosna River in Bosnia and Herzegovina on May 14, 2014. Here is a video of the bridge before it was swept away.
"Fishnado" in Sri Lanka
On May 5, 2014, residents of Chilaw, Sri Lanka were surprised by a rain of 50 kg (110 pounds) of live fish, 5 - 8 cm in length. MODIS satellite images from May 5 show an intense string of heavy thunderstorms formed over the island, and it is likely that one of these storms was a supercell thunderstorm that spawned a tornado which sucked up fish out of a nearby river and then spat them out over Chilaw. Such rains of fish are rare but not unheard of; as I outlined in my blog post on the ridiculous "Sharknado" movie that aired last year, there have been numerous reports of waterspouts or tornadoes picking up fish out of the sea or out of lakes and creating a "rain of fish." For example, hundreds of perch bombarded residents of the small Australian outback town of Lajamanu in 2010. In the U.S., thousands of small fish, frogs and crayfish fell from the sky during a rainstorm at Magnolia Terminal near Thomasville, Alabama, on the morning of June 28, 1957. Many of the fish were alive and were placed in ponds and swimming pools. An F2 tornado fifteen miles to the south spawned by the outer bands of Hurricane Audrey was likely responsible for getting the creatures airborne. William Corliss' intriguing book, "Handbook of Unusual Natural Phenomena", has an entire chapter devoted to unusual creatures and objects that have fallen from the sky. He relates that in 1946, a scientist at the American Museum of Natural History named E. W. Gudger documented 78 reliable reports of fish falls from all over the world. The largest fish was a large-mouthed bass 9 1/4 inches long, and the heaviest was a six pound fish that fell in India. There were no reports of large, 2000-pound great white sharks, as depicted by "Sharknado", though. Speaking of Sharknadoes, the much-anticipated sequel to "Sharknado", "Sharknado 2: The Second One" is scheduled to hit the air on the Syfy Channel on July 31, 2014. Yes, once again, bloodthirsty man-eating tornado-hurled sharks will terrorize a major American city--this time, New York. According to deadline.com, The Asylum, which is working on the sequel, has come up with a plan to use Indiegogo to raise $50,000 to create another scene for the new movie. Those who contribute to the campaign, which runs through May 30, will get some Sharknado 2 swag and an exclusive window on production, from behind-the-scenes footage to breaking news and advance DVD copies. Al Roker will make a cameo appearance in the film as himself.
Video 2. Villagers collect live fish that rained from the sky on May 5, 2014, in Chilaw, Sri Lanka.
Have a great weekend, everyone!
Updated: 2:38 PM GMT on May 16, 2014
By: JeffMasters, 2:21 PM GMT on May 15, 2014
Record May heat sent temperatures soaring above 100° in much of Southern California on Wednesday, and fierce Santa Ana winds fanned fires that scorched at least 9,000 acres in San Diego County, forcing thousands to evacuate. Los Angeles Airport hit 96° on Wednesday, which is the hottest May temperature on record NOAA's Threaded Extremes website (though apparently these records are not correct, since NWS Los Angeles says the all-time May record is 97°.) All-time May record heat was recorded at Camarillo (102°) and Oxnard (102°) on Wednesday. In Downtown Los Angeles, the mercury hit 99° on Wednesday, falling short of the all-time May record is 103° set on May 25, 1896. More record heat is forecast on Thursday, and hot offshore Santa Ana winds will bring extreme fire danger.
Figure 1. A firenado in Fallbrook, California at old Highway 395 and Interstate 15 on May 14, 2014. Image credit: Jena Rents via Twitter.
Figure 2. True-color MODIS satellite image of fires burning in Southern California and Northern Mexico on Wednesday afternoon, May 14, 2014. Image credit: NASA.
100% of California in severe to exceptional drought
Today's U.S. Drought Monitor report showed grim news for California: 100% of the state is now in severe or higher drought, up from 96% the previous week. Though just 25% of California is classified as being in the highest level of drought, "Exceptional", Erin McCarthy at the Wall Street Journal estimates that farms comprising 53% of California's $44.7 billion market value lie in the Exceptional drought area. Averaged state-wide, the Palmer Drought Severity Index during April 2014 was the second worst on record, behind 1977. For the 12-month period ending in April, drought conditions in California for 2013 - 2014 were also the second most severe on record, slightly below the 2008 - 2009 drought. To break the drought, most of the state needs 9 - 15" or precipitation to fall in one month. This amounts to more than a half-year's worth of precipitation for most of the state.
Figure 3. The May 13, 2014 U.S. Drought Monitor showed 100% of California in severe or higher drought, with 25% of the state in the highest level of drought, "Exceptional." Image credit: U.S. Drought Monitor.
California's rainy season is over
The California October through April rainy season is now over. Between October 2013 and April 2014, the state received 10.44" of precipitation, which is just 51% of average for the period, and the third lowest such total on record. Going back to 1895, the record low mark was set in 1976 - 1977, when the state got just 34% of its average rainy season precipitation. California typically receives less than 10% of its annual precipitation between May and September, and the coming hot and dry summer in combination with a severely depleted Sierra snowpack will cause a severe fire season and significant agricultural damages. The fifth and final snow survey of the season on May 1 found that the statewide snowpack’s water content--which normally provides about a third of the water for California’s farms and cities--was only 18% of average for the date. Already, the 2014 drought has cost the state at least $3.6 billion in agricultural damages, the California Farm Water Coalition estimates. CAL FIRE recently announced it had hired 125 additional firefighters to help address the increased fire threat due to drought conditions.
Video 1. Aerial views of the Southern California fires from Reuters. Thanks to wunderground member Skyepony for posting this link in my blog comments.
California Drought/Polar Vortex Jet Stream Pattern Linked to Global Warming, my April 16, 2014 post
I've done four posts this year on ways to get more water for the thirsty Southwest:
1) Conservation measures
2) Cloud seeding
3) Desalinization plants
4) Enormous Water Works Programs
Updated: 12:59 PM GMT on May 16, 2014
By: JeffMasters, 6:01 PM GMT on May 13, 2014
Human-caused global warming has set in motion an unstoppable slow-motion collapse of the glaciers in West Antarctica of massive scale and power, said scientists at a NASA press conference and press release on Monday. The scientists, led by glaciologist Eric Rignot of NASA's Jet Propulsion Laboratory/the University of California, Irvine, analyzed 19 years of satellite data to show that the fast-melting glaciers that drain into West Antarctica's Amundsen Sea had passed a point of no return, since their bottoms are grounded below sea level. The glaciers had been lodged on "pinning points" on the bedrock--projections that snagged the glaciers from underneath and kept them from sliding toward the sea. Melting due to warmer ocean waters has been eating away the glaciers from beneath, freeing them from their pinning points, and setting in motion a slow-motion collapse that appears "unstoppable", Rignot said at the press conference. The glaciers contain enough ice to raise global sea level by 4 feet (1.2 meters) in a few hundred years at their current rate of melting, Rignot added. The research has been accepted for publication in the journal Geophysical Research Letters.
Figure 1. Thwaites Glacier, the West Antarctic glacier that is the most serious threat to bring large levels of sea level rise this century. Image credit: NASA.
Computer modeling study shows same result
A separate paper published on Monday in Science, Marine Ice Sheet Collapse Potentially Under Way for the Thwaites Glacier Basin, West Antarctica, came to a similar result, but using computer modeling instead of observations. The researchers, led by Ian Joughin of the University of Washington, found that West Antarctica's fast-moving Thwaites Glacier will likely disappear in a matter of centuries, raising sea level by nearly 2 feet. “All of our simulations show it will retreat at less than a millimeter of sea level rise per year for a couple of hundred years, and then, boom, it just starts to really go,” Joughin said. The Thwaites Glacier acts as a linchpin on the rest of the ice sheet, which contains enough ice to cause another 10 to 13 feet (3 to 4 meters) of global sea level rise. For comparison, 119,000 - 126,000 years ago, during the period before the most recent ice age, global sea levels were 16 - 33 feet (5 - 10 meters) higher than at present. Temperatures at that time were less than 2°C warmer than "pre-industrial" levels, and we are on track to warm the planet at least that much this century.
Figure 2. Historical global sea level rise from 1700 - 2012 as compiled by the 2013 IPCC report, along with predicted sea level rise from the IPCC and from a group of 26 ice sheet experts (Bamber and Asplinall, 2013). Sea level rose 7.5" (19 cm) between 1901 - 2012, with the rate of rise nearly doubling over the past 20 years. The low-end RCP 2.6 IPCC forecast corresponds to global warming of just 1°C between 1995 - 2100, which will be nearly impossible to achieve. Humanity is currently on pace to warm the planet more than IPCC's worst-case RCP 8.5 scenario (3.7°C between 1995 - 2100.) Before Monday's research results were announced, the IPCC sea level rise estimates were already viewed as quite conservative by the majority of sea level rise experts; see the write-up at real climate.org of the Bamber and Asplinall, 2013 study.
IPCC sea level rise estimates too low?
At the press conference, the scientists questioned the sea level rise estimates made by the Intergovernmental Panel on Climate Change (IPCC) in September 2013 as being too low. That report projected that sea level will rise by an extra 0.9 - 3.2' (26 to 98 cm) by 2100. The IPCC did not fully account for potential melting in Antarctica, and decided not to include estimates from at least five published studies that had higher numbers, including two studies with rises of 2 meters (6.6 feet.) This is in contradiction to NOAA's December 2012 U.S. National Climate Assessment Report, which has 6.6 feet (2.0 meters) as its worst-case sea level rise scenario for 2100.
Video 1. ScienceCasts: No Turning Back--West Antarctic Glaciers in Irreversible Decline
Updated: 6:13 PM GMT on May 13, 2014
By: JeffMasters, 4:01 PM GMT on May 12, 2014
For the first time since the fall of 2012, weekly-averaged sea surface temperatures (SSTs) in the equatorial Pacific have reached the threshold needed for an El Niño event to be declared. By definition, an El Niño episode occurs when SSTs are at least +0.5°C from average for three consecutive months in the region 120°W - 170°W, 5°S - 5°N (called the Niño 3.4 region.) The weekly ENSO update issued by NOAA on May 12, 2014, put ocean temperatures in this Niño 3.4 region for the past seven days at +0.5°C from average. An El Niño event is still not a sure thing, though. We saw similar behavior in the fall of 2012, with SSTs warming up above the +0.5°C threshold, prompting NOAA to issue an El Niño Watch. However, the ocean SSTs were not able to hold for the required three month period, and no El Niño event ended up happening. However, this year the odds appear more favorable. NOAA has issued an El Niño Watch for the summer and fall of 2014, giving a greater than 65% chance that an El Niño event will occur during summer, a boost upwards from their >50% chance given the previous month. The May 8 El Niño discussion from NOAA's Climate Prediction Center noted that "There remains uncertainty as to exactly when El Niño will develop and an even greater uncertainty as to how strong it may become. This uncertainty is related to the inherently lower forecast skill of the models for forecasts made in the spring." None of the El Niño models (updated in mid-April 2014) predict La Niña conditions for peak hurricane season, August-September-October 2014, and 16 of 20 predict El Niño conditions. There is currently not a strong Westerly Wind Burst (WWB) over the equatorial Pacific Ocean helping push warm water eastwards towards South America. There have been three of these WWBs so far in 2014, and if we get one more in the next month or two, that should be enough to push the system into a full-fledged El Niño event.
Figure 1. Departure of sea surface temperature (SST) from average for May 12, 2014. A plume of warmer-than-average temperatures stretched along the equatorial Pacific from the coast of South America westwards into the Western Pacific, a harbinger of a developing El Niño event. Image credit: NOAA.
El Niño events usually lead to quiet Atlantic hurricane seasons
El Niño conditions tend to make quieter than average Atlantic hurricane seasons, due to an increase in upper-level winds that create strong wind shear over the Tropical Atlantic. The last official El Niño event occurred from summer 2009 - spring 2010, and as expected, the 2009 Atlantic hurricane season was a relatively quiet one, with 11 named storms, 3 hurricanes, and 2 major hurricanes. No 2009 hurricanes got their names retired, and there were only six fatalities.
NOAA Launches ENSO Blog
Just in time for the likely arrival of El Niño comes the new NOAA ENSO Blog (ENSO is the acronym for “El Niño - Southern Oscillation”, which is the more scientifically rigorous term for what I typically refer to as “El Niño.") The blog is written by a team of three veteran El Niño scientists:
• Anthony (Tony) Barnston, chief forecaster at the International Research Institute (IRI) for Climate and Society
• Emily Becker, a researcher at the NOAA’s Climate Prediction Center (CPC)
• Michelle L’Heureux, who has led the team in charge of routinely producing NOAA/NWS/CPC’s ENSO updates and outlooks since 2006
They have not yet enabled comments, but they expect to do so within the next week or two. I look forward to seeing their expert commentary.
By: JeffMasters, 3:47 PM GMT on May 08, 2014
Category 5 Super Typhoon Haiyan, with satellite-estimated winds of 190 - 195 mph at landfall on November 8, 2013, pushed a massive storm surge of up to 23 feet (7 meters) into Tacloban, Philippines, newly-published storm surge survey results reveal. A team of researchers led by Yoshimitsu Tajima of the Department of Civil Engineering at the University of Tokyo found that at Haiyan's initial landfall point on the east coast of Samar Island, massive waves on top of the storm surge crashed against the coast, creating high water marks an astonishing 46 feet (14.1 meters) above mean sea level--some of the highest high-water marks ever recorded from a tropical cyclone. The world record is 13 - 14.6 meters (43 - 48 feet) from Australia's March 5, 1899 Bathurst Bay Cyclone. The greatest storm surge and high water mark recorded in an Atlantic hurricane are from Hurricane Katrina of 2005, which had a peak storm surge in Pass Christian, Mississippi of 27.8 feet (8.46 meters). The sea bottom was very flat in this region, so the waves on top of the surge were relatively small, and the highest high water mark from Katrina was just a few inches higher, at 28 feet (8.53 meters.) When deep water lies just offshore, as is the case for the east coast of the Philippines' Samar Island, huge waves will develop when the eyewall of an intense tropical cyclone moves over. These huge waves broke very close to shore during Haiyan, and were able to run-up the steep hillsides to incredible heights.
Figure 1. High water marks (in meters) in the wake of Super Typhoon Haiyan's storm surge in the Philippines on November 8, 2013. Numbers with "V" had significant waves on top of the storm surge; "R" indicates wave run-up height (where waves on top of the surge allowed the water to run-up onto shore much higher than the actual surge height), and symbols without letters are still water inundation (storm surge) heights. The high water marks are corrected for the tide levels at the time of the survey (tidal range in the Central Philippines is generally less than 1 meter, so this is a small correction in most cases.) The data is plotted from the survey results of Tajima et al., 2014.
Results of the storm surge survey
Andrew Kennedy, Associate Professor in Notre Dame's Department of Civil & Environmental Engineering & Earth Sciences, was part of a second Super Typhoon Haiyan storm surge survey done in January 2014 (whose results have not yet been published), and wrote this email to me: "We surveyed many locations concentrating on the open Pacific coast of Eastern Samar, just north of first landfall. The team was led by Professor Yoshimitsu Tajima of the University of Tokyo. We are still processing results, but found many locations with wave run-up in the 9 - 10 meter range. These waves and surge tossed palm trees, large boulders, and other debris up to elevations that would seem improbable if you had not seen the evidence. The communities affected by this storm remain devastated, and there is still no power in Guiuan, the largest city in Eastern Samar and our base for part of the survey. In addition to the inundation, we also looked a lot at damage--mainly from waves and surge, but partly from wind. This included the small Barangay (town) of Hernani, the location of the frightening Nixon Gensis video showing waves washing away a house. We interviewed many people both in Hernani and other locations who described similar experiences of very sudden destructive inundation. I will say it again: ten meter run-up is hard to believe if you haven’t seen it."
Video 1. Nickson Gensis, Plan Philippines Community Development Worker, filmed what is probably the most remarkable video of storm surge ever taken. The video was taken from the from the top floor of a boarding house during Super Typhoon Haiyan in Hernani, in Eastern Samar, Philippines on November 8, 2013. Australian tropical cyclone expert Bruce Harper had this to say about the remarkable "tsunami-like" storm surge observed at 46 seconds into the video: This site at Hernani is quite exposed on the eastern coast of Samar, and has a fringing reef. My guess is that we are seeing the sudden exposure to deep water ocean swell waves that were triggered by the tide and sea level increase due to the storm surge. There is a critical water level where waves impacting on reefs can suddenly cause a massive increase in wave setup in the form of a tsunami-like effect such as we see in the video. A similar effect was reported at Basey, ten miles to the northeast of Tacloban across the San Juanico Strait, in this news report: "Edgar dela Cruz, 45, of Barangay Mercado, recounted to The STAR the sight of what looked like a tsunami. During the strange lull in the typhoon, he went out of his house. Jinamok Island was a kilometer across the sea from his village, he said. The sea receded about halfway to the island. 'There was a kind of low black cloud moving toward us,' Dela Cruz said. 'We heard a loud boom, like an explosion. And then we saw the giant waves--four giant waves--it was horrible.' Their house was destroyed. He said he and his family escaped with only the clothes on their backs." In this case, the reports suggest that northeast winds ahead of the center of Haiyan caused an initial “negative surge” effect in the shallow waters in this area, followed by the winds turning to E and SE as the center came closer. You can then develop quite a gradient in the water levels capable of producing this effect. The fast speed of the storm may also have contributed to this specific phenomenon. Yao Zhang of Notre Dame's Department of Civil & Environmental Engineering & Earth Sciences has modeled the waves and surge at Hernani, Eastern Samar, using a one-dimensional Boussinesq model. These show periodic surges and recessions very similar to those seen by Nickson Gensis. Magnitudes are quite large--over 5 meters--which does not include any initial storm surge. The simulations are not perfectly accurate, due to the lack of perfect bathymetry and incident waves. A video of one of his model runs may be seen at http://www.youtube.com/watch?v=KPYGQCE3778. The middle plot is a zoomed-in version of the larger-scale version shown in the top panel.
Figure 2. Storm surge damage from Super Typhoon Haiyan on Victory Island, Samar. Image credit: Getty Images.
A deadly storm surge for Tacloban
Tacloban (population 221,000) is the largest city on the Philippines' east coast, and is low-lying, with much of the city at less than ten feet elevation. Its position at the pointy end of a funnel-shaped bay makes its location particularly vulnerable to storm surge, since the topography acts to concentrate water at the apex of the funnel. The storm surge in Tacloban from Haiyan ranged from 4.6 - 7.0 meters (15 - 23 feet) according to the survey results, and caused catastrophic loss of life. An April 17, 2014 report from the Philippine National Disaster Risk Reduction and Management Council listed 7,361 people dead or missing from Haiyan, making the typhoon the deadliest disaster in Philippine history. Most of these deaths occurred due to the storm surge in the Tacloban region. According to storm surge expert Dr. Hal Needham, the record highest storm surge in modern history in East Asia was 24 feet (7.3 meters) in 1897 on Samar Island, Philippines--the same location where Haiyan initially hit.
Video 2. This animation by Deltares shows computed storm surge levels and wind vectors as Super Typhoon Haiyan makes landfall near Tacloban City, The Philippines. Surge levels were computed using Delft3D two days after landfall. The wind fields are based on Joint Typhoon Warning Center data, and generated a simulated storm surge of over 16.4 feet (5 meters) for Tacloban.
Tajima, Y., et al., 2014, Initial Report of JSCE-PICE Joint Survey on the Storm Surge Disaster caused by Typhoon Haiyan, Coastal Engineering Journal Volume 56, Issue 01, March 2014.
A detailed look at Haiyan's storm surge, my December 2013 blog post.
(An interesting side note: I talked to a journalist who traveled to Eastern Samar after Haiyan hit. She talked to a worker who sheltered at the radar site in Guiuan that had its radome blown off during the height of the storm. The worker reported that they measured a pressure of 892 mb as the eye passed over. I haven't heard anything official out of the Philippines about this measurement, though, and the official landfalling pressure of Haiyan remains the 895 mb estimated via satellite by the Japan Meteorological Agency.)
Video 3. Palo, Philippines, located just south of Tacloban, was located in a more intense part of the eyewall of Super Typhoon Haiyan, as is evident by the remarkable extreme winds and storm surge captured in this video. According to storm chaser Josh Morgerman, the most extreme damage occurred a little farther south than Palo, in Tolosa and Tanauan.
Video 4. The storm surge in Tacloban, Philippines during the landfall of Super Typhoon Haiyan is captured at about the 3:30 - 4:20 mark in this video shot by ABSCBN News of the Philippines.
My next post will be Monday at the latest.
Updated: 1:29 PM GMT on May 09, 2014
By: JeffMasters, 2:02 PM GMT on May 06, 2014
Climate change, once considered an issue for a distant future, has moved firmly into the present,” begins a new 1,000+ page report on U.S. climate released May 6. The National Climate Assessment, issued every four years by NOAA, is an effort by more than 300 U.S. scientists to assess how the climate is changing in the U.S. The report was supervised and approved by a 60-member committee representing a cross section of American society, including representatives of two oil companies. “Summers are longer and hotter, and extended periods of unusual heat last longer than any living American has ever experienced,” the report continues. “Winters are generally shorter and warmer. Rain comes in heavier downpours. People are seeing changes in the length and severity of seasonal allergies, the plant varieties that thrive in their gardens, and the kinds of birds they see in any particular month in their neighborhoods.” The National Climate Assessment lists hotter heat waves, more intense droughts, coastal inundation due to rising seas, heavier downpours, melting of glaciers and permafrost, bigger wildfires, worsening air pollution, stronger storms, increased diseases transmitted by insects, food, and water, and threats to mental health, as being of particular concern for Americans. If you want a thorough understanding of how climate change is affecting and will affect the U.S., this highly readable document is a great one to read, and I plan to frequently reference it in the coming years. Coming on the heels of a major 3-part report released by the United Nations Intergovernmental Panel on Climate Change (IPCC) in September - April, the National Climate Assessment presents the same key themes: climate change is already having widespread impacts and will get much worse, but there are cost-effective measures we can take to adapt to it and help reduced it. “Climate change presents a major challenge for society,” the report warns. “There is mounting evidence that harm to the nation will increase substantially in the future unless global emissions of heat-trapping gases are greatly reduced.” What’s particularly handy about the NCA is that it is U.S.-specific, and discusses in great detail the specific impacts in eight different regions of the U.S.: Northeast, Southeast and Caribbean, Midwest, Great Plains, Southwest, Northwest, Alaska, and Hawaii and Pacific Islands. I present here a few highlights.
Wet areas will get wetter, and dry areas will get drier. To me, this is the key finding of the NCA. As shown in Figure 1 below, the water-rich will get richer, and the water-poor will get poorer. This pattern will increase the costs of both droughts and floods, and make it harder to grow crops, on average, when the nation-wide impact is considered.
Figure 1. Difference in precipitation (in percent) between the observed 1970 - 1999 period, and the 30-year period centered on 2084, as predicted by 15 climate models used to formulate the 2007 IPCC climate report. The models assumed a relatively high-emissions scenario (A2), though not as high as the path humanity is currently on. The results show a key prediction of the future for North America: wet areas are expected to get wetter, and dry areas are expected to get drier. The predicted summer dryness across the major grain-growing areas of the U.S. is of particular concern, since increases in dryness will make is harder to grow food. Image credit:
Agriculture: “Climate disruptions to agriculture have been increasing and are projected to become more severe over this century. Some areas are already experiencing climate- related disruptions, particularly due to extreme weather events. While some U.S. regions and some types of agricultural production will be relatively resilient to climate change over the next 25 years or so, others will increasingly suffer from stresses due to extreme heat, drought, disease, and heavy downpours. From mid-century on, climate change is projected to have more negative impacts on crops and livestock across the country – a trend that could diminish the security of our food supply... Climate change effects on agriculture will have consequences for food security, both in the U.S. and globally, through changes in crop yields and food prices and effects on food processing, storage, transportation, and retailing. Adaptation measures can help delay and reduce some of these impacts.”
Water: “The Southwest, Great Plains, and Southeast are particularly vulnerable to changes in water supply and demand. Changes in precipitation and runoff, combined with changes in consumption and withdrawal, have reduced surface and groundwater supplies in many areas. These trends are expected to continue, increasing the likelihood of water shortages for many uses. Increasing flooding risk affects human safety and health, property, infrastructure, economies, and ecology in many basins across the United States.”
Heavy Downpours: “Heavy downpours are increasing nationally, especially over the last three to five decades. Largest increases are in the Midwest and Northeast. Increases in the frequency and intensity of extreme precipitation events are projected for all U.S. regions.”
Figure 2. Percent changes in the amount of precipitation falling in very heavy events (the heaviest 1%) from 1958 to 2012 for each region. There is a clear national trend toward a greater amount of precipitation being concentrated in very heavy events, particularly in the Northeast and Midwest. Image credit: NCA Overview, updated from Karl et al. 2009.
Extreme Weather: “There have been changes in some types of extreme weather events over the last several decades. Heat waves have become more frequent and intense, especially in the West. Cold waves have become less frequent and intense across the Nation. There have been regional trends in floods and droughts. Droughts in the Southwest and heat waves everywhere are projected to become more intense, and cold waves less intense everywhere.”
Hurricanes: “The intensity, frequency, and duration of North Atlantic hurricanes, as well as the frequency of the strongest (Category 4 and 5) hurricanes, have all increased since the early 1980s. The relative contributions of human and natural causes to these increases are still uncertain. Hurricane-associated storm intensity and rainfall rates are projected to increase as the climate continues to warm.”
Severe Storms: “Winter storms have increased in frequency and intensity since the 1950s, and their tracks have shifted northward over the United States. Other trends in severe storms, including the intensity and frequency of tornadoes, hail, and damaging thunderstorm winds, are uncertain and are being studied intensively.”
Oceans: “Ocean waters are becoming warmer and more acidic, broadly affecting ocean circulation, chemistry, ecosystems, and marine life. More acidic waters inhibit the formation of shells, skeletons, and coral reefs. Warmer waters harm coral reefs and alter the distribution, abundance, and productivity of many marine species. The rising temperature and changing chemistry of ocean water combine with other stresses, such as overfishing and coastal and marine pollution, to alter marine-based food production and harm fishing communities.” The NCA website has an impressive interactive graphic with a slider that allows one to see the impact of acidification on a pteropod’s shell.
The official roll-out of the NCA will occur at 2pm EDT May 6 from the White House, and will be webcast live at http:/www.whitehouse.gov/live. According to Andrew Freedman at Mashable, eight television meteorologists are slated to have rare one-on-one interviews about global warming with President Barack Obama on Tuesday, including Al Roker, co-anchor of NBC's Today Show; Ginger Zee, meteorologist on ABC's Good Morning America; John Morales, chief meteorologist of NBC 6 in Miami, Florida; and Jim Gandy, meteorologist of WLTX-TV in Columbia, South Carolina. President Obama also previously did an interview on climate change with a crew from Showtime's documentary series "Years of Living Dangerously”; the interview is scheduled to air sometime in the next few months.
Unlike the IPCC report, the U.S. National Climate Assessment is plainly written, easy-to-understand, and has an excellent web site with nice graphics, some of them interactive. I highly recommend perusing the Overview section of the NCA website to get a quick summary of their findings. They've also made available a collection of short videos.
I’ll have a new post on Thursday.
Updated: 8:19 PM GMT on May 06, 2014
By: JeffMasters, 5:24 PM GMT on May 01, 2014
The deadly and devastating U.S. severe weather outbreak of April 27 - 30, 2014, has finally drawn to a close. The death toll from nature’s 4-day rampage of deadly tornadoes, extreme flooding, and damaging severe thunderstorms has killed at least 39 people, and will end up costing more than $1 billion, according to disaster expert Steve Bowen of Aon Benfield. NOAA’s Storm Prediction Center (SPC) lists 133 preliminary tornadoes over the four days in 14 states; damage surveys are on-going, and 38 of these tornadoes had been confirmed as of noon on May 1.
Figure 1. Rainfall derived from the TRMM' satellite’s Microwave Imager (TMI) and Precipitation Radar (PR) data is shown overlaid on GOES-EAST infrared satellite images captured on April 29, 2014 at 0402 UTC and 0532 UTC. Red symbols show the locations where numerous tornadoes were reported from Monday afternoon through Tuesday morning. Image credit: NASA.
Extreme rainfall and flooding in Pensacola and Mobile
Torrential rains on Tuesday night in Pensacola, Florida brought an all-time calendar-day record of 15.55” of rain to the city. The old calendar day record of 15.29" in October 1934 was due to a tropical storm that made landfall just to the west of the city. Mobile, Alabama saw 11.24" during the calendar day on Tuesday, their 3rd greatest calendar day total on record. The Pensacola Airport recorded a remarkable 5.68 inches of rain in just one hour ending at 10 pm Tuesday night, and numerous high-water rescues had to be performed Tuesday night and Wednesday morning. One drowning occurred, in a vehicle that tried to cross flooded Highway 29. According to a nice flood event summary from the Mobile/Pensacola NWS, the 5.68" that fell in 1 hour was between a 1 to 200 and 1 to 500 year event, and the two day estimated total for Pensacola of 20.47" lies between a 1 in 100 to 1 in 200 year event. As discussed by Andrea Thompson at Climate Central, these type of extreme precipitation events have increased in the U.S. in recent decades, are are expected to continue to increase as a warming climate puts more moisture into the atmosphere. A comparison for perspective: Wichita, Kansas is having it's second driest start to the year since 1936, with 2.01” since January 1, 2014; Pensacola received 2 1/2 times as much rain in one hour than Wichita has seen all year. Pensacola finished April with 29.53” of rain, breaking the all-time record for any month (not just April) of 24.46” set in April 2005. This also makes it the wettest year-to-date on record in Pensacola.
Figure 2. Natural gas leaks spray into the sky on Piedmont Street in the Cordova Park neighborhood in Pensacola, Florida, after the road washed out due to heavy rains on April 30, 2014. (Photo by Marianna Massey/Getty Images)
Video 1. Aerial drone footage of the Scenic Highway near Pensacola, Florida, after being washed out by extreme flooding on April 30, 2014. Another YouTube drone video here of the Pensacola flooding also shows the impressive scale of the event.
Heavy rains and flooding in the Mid-Atlantic and Northeast
The storm also brought heavy rains and damaging flooding to much of the Mid-Atlantic and Northeast on Wednesday. The 4.97" that fell in New York City at Central Park was the Big Apple’s 2nd wettest April day on record, behind the 7.57" that fell on April 15, 2007. In Pennsylvania, during a nine-hour period that ended early Thursday, Chester County got 6.6 “ of rain, Delaware and Montgomery counties got 5.5”, and Philadelphia nearly 5 inches. At least 62 people were rescued overnight in Chester County from their vehicles, most after driving past closed road signs and barriers. Heavy rains in Baltimore caused a washout of a retaining wall, causing multiple cars to plunge down into a flooded railway line.
Figure 3. View of the Charles Village, Baltimore retaining wall collapse near 26th St on April 30, 2014. There were no injuries, but at least six cars plunged down onto the CSX railroad tracks below. According to meteorologist Justin Berk, who took the photo, local residents said they have had concerns about this wall for a long time.
Two EF-4 tornadoes from the outbreak
At least two EF-4 tornadoes have been surveyed so far from the outbreak, and there may be others once damage surveys are complete:
Vilonia, Arkansas: A violent high-end EF-4 tornado with winds of 180 - 190 mph tore through Vilonia and Mayflower, Arkansas on April 27, killing 15 people. This tornado was also the widest (3/4 mile) and longest lived (60 minutes) twister of the outbreak. There is a report that the tornado picked up a truck in Mayflower and deposited it in a field northeast of Vilonia, 27 miles away. Update: When contacted about this again by a reporter, the man who's car was transported admitted some confusion about where his car had been parked at the time of the tornado, so this remarkable story is dubious.
Louisville, Mississippi: An EF-4 with 185 mph winds hit Louisville, Mississippi on April 28. The tornado killed nine people, carved a path 35 miles long and up to 3/4 mile wide, and stayed on the ground for 56 minutes. The tornado carried a door 30 miles from Louisville and deposited it on the Mississippi State University campus.
The longest path tornado of the event was an EF-1 twister with a path length of 46 miles that stayed on the ground 46 minutes, and killed two people near Martinsburg and Kinross, Iowa on April 27.
Figure 4. Volunteers help clean up debris where homes once stood after the area was hit by a tornado April 29, 2014 in Vilonia, Arkansas. (Photo by Mark Wilson/Getty Images)
Video 2. Aerial drone footage of tornado damage from April 28, 2014 in Bessemer, Alabama just west of Birmingham. The EF-2 tornado with maximum winds of 120 mph stayed on the ground 4.9 miles and hit a golf course and an apartment complex, with a near miss of the Bessemer Hospital. It’s remarkable to see the huge number of trees pulled out by their roots. According to an article in Forbes, “The FAA claims the broad authority to prohibit the ‘commercial’ use of drones, and has included the use of drones for journalism or search and rescue under that ban. The FAA’s determination comes despite having lost an enforcement action at the administrative judge level….Despite the clear value of drones in disaster response and search and rescue operations, one search and rescue group based out of Texas has been forbidden from flying their drones in search and rescue operations, prompting them to sue the federal government. That case has sent a message to all would be search and rescue groups, letting them know they should keep their drones grounded, lest they face fines for trying to help find lost persons.”
U.S. billion-dollar weather-related disasters of 2014
1) The January 5 - 8 "Polar Vortex" winter weather outbreak, which Aon Benfield estimated caused $3 billion in damage.
2) The California drought, with $3.6 billion in agricultural damages so far, as estimated by the California Farm Water Coalition.
3) Severe weather outbreak of April 27 - 30, which Aon Benfield estimated caused $1+ billion in damage.
Disaster Relief Donations Needed
The devastation from this week’s tornadoes have brought a need for donations for disaster relief. The Portlight.org disaster relief charity, founded by members of the wunderground community, is supporting the efforts of a group of local volunteers in Arkansas doing search and rescue, and needs donations. Portlight volunteers are working in tornado-hit towns to clear debris and help with other clean-up efforts. This team will also be visiting shelters and reaching out to survivors with disabilities to determine their immediate needs, whether for replacement of durable medical equipment and ramps, or for assistance with shelter and transportation issues. The Red Cross is also a great place to send your donation dollars.
This will likely be my last post until Tuesday afternoon, as I plan on taking a few days off.
Updated: 12:37 AM GMT on May 02, 2014