A momentous two weeks of United Nations meetings that will shape the future of Earth’s climate have begun. The 21st annual UN Conference on Climate Change (also known as the Conference of Parties, or COP21) will unfold at Le Bourget, France, about six miles northeast of downtown Paris. COP21 is bringing together some 40,000 diplomats, scientists, journalists, and observers, as well as 151 heads of state--the largest such gathering of world leaders in history. This year’s meeting represents the best chance at a workable global agreement since Copenhagen--and perhaps our last chance for a long time to come. What makes COP21 so critical?
Bob Henson • 3:51 PM GMT on November 30, 2015
Tropical Storm Sandra was shredded apart by 50 knots of wind shear early Saturday morning before the storm could make landfall on the Pacific coast of Mexico, ending the reign of this most unusual late-season storm. Earlier in the week, Sandra set the record for the latest major hurricane ever observed in the Western Hemisphere.
Jeff Masters • 3:24 PM GMT on November 28, 2015
After becoming the latest major hurricane on record in the Western Hemisphere, a weakening Hurricane Sandra (top winds of 100 mph on Friday morning] remained on track Friday for a history-making landfall as a tropical storm early Saturday on the coast of Mexico’s Sinaloa state. Energy and moisture from Sandra will flow toward Texas this weekend, in the wake of the wettest Thanksgiving Day on record in a number of central U.S. cities. Flooding and icing will be a major threat Friday and Saturday across parts of the Southern and Central Plains.
Bob Henson and Jeff Masters • 4:36 PM GMT on November 27, 2015
Remarkable Hurricane Sandra exploded into a Category 4 storm with 145 mph winds overnight, making it the latest major hurricane ever observed in the Western Hemisphere. The previous record was held by an unnamed Atlantic hurricane in 1934 that held on to Category 3 status until November 24.
Jeff Masters and Bob Henson • 4:18 PM GMT on November 26, 2015
Holiday travel during the busy Saturday/Sunday Thanksgiving weekend across portions of the Southern Plains will get disrupted by a most unusual occurrence--flooding rains and a potential ice storm, enhanced by moisture from the strongest Eastern Pacific hurricane observed so late in the year. Declared a hurricane on Tuesday night, Sandra may reach Category 3 strength before weakening and approaching the Mexican coast on Friday or Saturday. Sandra's moisture will feed into a large-scale heavy rain event: flash flood watches are already in effect from far north Texas to southwest Illinois .On the northwest edge of the heavy rain swath, there should be a parallel strip with low-level temperatures cold enough for mostly light but widespread freezing rain, sleet, and/or snow, with an initial round from Thanksgiving Day into Friday and perhaps a second batch over the weekend as another lobe rotates around the sprawling upper-level low.
Bob Henson and Jeff Masters • 5:51 PM GMT on November 25, 2015
Tropical Storm Sandra, which formed on Tuesday morning in the record-warm Pacific waters off the south coast of Mexico, is expected to become a hurricane and could become the latest landfalling tropical cyclone in Northeast Pacific records. Moisture from Sandra will flow toward the Southern Plains, upping the odds of torrential rain from Texas to Arkansas over the Thanksgiving holiday weekend. Freezing rain and snow are possible from the Texas Panhandle to eastern Nebraska.
Jeff Masters and Bob Henson • 4:05 PM GMT on November 24, 2015
An area of disturbed weather in the record-warm Pacific waters off the south coast of Mexico may become Tropical Storm Sandra by Wednesday, potentially becoming a hurricane and threatening the coast of Mexico this weekend near the tip of the Baja Peninsula. Meanwhile, the weekly value of El Niño warmth in the eastern tropical Pacific has hit a new record, and a compact, intense snowstorm socked the Midwest on Friday and Saturday, bringing Chicago its heaviest snow on record so early in the autumn.
Jeff Masters and Bob Henson • 5:22 PM GMT on November 23, 2015
The amount of carbon dioxide measured daily in the air at Mauna Loa, Hawaii, may have dipped below 400 ppm for the last time in our lives. This and several other recent milestones serve as a prelude to the upcoming United Nations climate talks in Paris, where plans for major public events have been scuttled in the wake of the November 13 attacks.
Bob Henson • 5:18 PM GMT on November 20, 2015
With gusts as high as 137 mph, one of the most widespread and damaging bouts of high wind to strike the Northwest U.S. in years caused at least 4 deaths and left more than 1 million people without power. In the Northeast Pacific, Tropical Storm Rick has become one of the latest-forming tropical storms since accurate records began in 1949. In the Western Pacific, Typhoon In-fa, unusually close to the equator, is expected to pass south of Guam at Category 3 strength.
Bob Henson and Jeff Masters • 5:55 PM GMT on November 19, 2015
Earth’s surface temperature has surged high into uncharted territory, thanks to a record-strength El Niño event combined with the long-term rise in temperatures due to human-caused global warming: October 2015 was Earth’s warmest month on record by a huge margin, according to data from NOAA and NASA.
Jeff Masters • 4:54 PM GMT on November 18, 2015
The latest tornado outbreak on record west of the 100th meridian left damage strewn late Monday across parts of western Kansas and the Oklahoma and Texas Panhandles. More severe weather and potential flash flooding is on tap for Tuesday across Arkansas and Missouri. Meanwhile, in the Pacific, developing Invest 90E may eventually pose a threat to Mexico, and intensifying Tropical Storm In-fa could threaten Guam as a Category 3 typhoon.
Bob Henson and Jeff Masters • 6:46 PM GMT on November 17, 2015
The El Niño event of 2015 has just set a record for the warmest waters ever observed in the equatorial Pacific over a 1-week period. SSTs in the Pacific between 90°W and 160°E longitude and 5° north/south latitude hit +3.0°C (5.4°F) from average over the past week, exceeding the previous 1-week record warmth of 2.8°C above average set during the week of November 26, 1997.
JeffMasters, • 4:44 PM GMT on November 16, 2015
If you’re looking for an old-fashioned holiday, you may be out of luck across large parts of the U.S. and Canada, at least when it comes to December cold. El Niño climatology and seasonal forecast models are pointing toward high odds of a very mild December across most of the continent east of the Rockies and north of the Deep South. We wouldn’t expect every day to be unusually balmy--and in December, “warmer than average” can still be quite chilly--but the analogue years and the model forecasts do raise the possibility of at least a few days of record-melting weather across a vast area.
Bob Henson • 5:43 PM GMT on November 13, 2015
The intense midlatitude storm that swept across the Great Plains on Wednesday, dropping several tornadoes across central Iowa, may produce the worst flooding in decades along the southeast shores of Lake Michigan on Thursday. The powerful surface low at the heart of the storm is being energized by a pocket of extremely strong winds (more than 170 mph) at upper levels, leading to widespread areas of 50 - 60 mph surface winds across and near the Great Lakes.
Bob Henson • 4:42 PM GMT on November 12, 2015
Hurricane Kate, the fourth hurricane of the 2015 Atlantic season, is racing east-northeast into the North Atlantic with top sustained winds of 75 mph. It will soon merge with a nontropical storm and potentially bring high winds and heavy rains to the British Isles, which will soon be hit by the first-ever winter storm to be officially named by the UK Met Office. Meanwhile, severe thunderstorms with a risk of tornadoes are predicted for parts of the Midwest on Wednesday.
Bob Henson • 5:10 PM GMT on November 11, 2015
Now packing top winds of 70 mph, Tropical Storm Kate is nearing hurricane status well east of Florida and Georgia as it begins sweeping into the open Atlantic, while Cyclone Meg made an improbable landfall in western Yemen. And it was 40 years ago today that a severe Great Lakes storm, later immortalized in song, led to the wreck of the SS Edmund Fitzgerald.
Bob Henson and Jeff Masters • 4:52 PM GMT on November 10, 2015
Tropical Storm Kate formed on Monday morning near the Central Bahamas, an unusual occurrence for November during an El Niño year (see below). Kate may approach hurricane strength as it curves north and northeast between the U.S. East Coast and Bermuda. In the Middle East, Cyclone Megh is heading toward the Yemen coast after raking Socotra Island at Category 3 strength, just a week after Cyclone Chapala did the same. The weekly El Niño update has matched the peak departure from normal observed during the record-setting 1997-98 event, and record-warm temperatures for November are being notched from the Southeast US to Europe.
Bob Henson and Jeff Masters • 5:23 PM GMT on November 09, 2015
Tropical Cyclone Megh powered ashore over Yemen's Socotra Island on Sunday morning as a major Category 3 storm with 125 mph winds. Interaction with land, entrainment of dry air from the nearby deserts, and encounters with cooler patches of water upwelled last week by the passage of Tropical Cylcone Chapala should continue to weaken Megh as it heads towards mainland Yemen.
Jeff Masters • 5:57 PM GMT on November 08, 2015
On Thursday, the American Meteorological Society (AMS) released its fourth annual special issue of the Bulletin of the AMS devoted to studies examining the links between climate change and extreme weather and climate events. New topics this year include tropical cyclones, forest fires, and anomalies in sea surface temperature and sea level pressure. For about half of the events studied in this year’s AMS report, scientists found that human-induced climate change played a measurable role in making the event stronger and/or more likely.
Bob Henson • 6:18 PM GMT on November 06, 2015
The North Indian Ocean may witness a very rare event this weekend: the existence of two simultaneous tropical cyclones in November--one in the Bay of Bengal and one in the Arabian Sea. Two disturbances in the Atlantic look like minimal threats to affect land areas as significant tropical cyclones.
Jeff Masters • 2:31 PM GMT on November 06, 2015
Cyclonic Storm Megh has formed over the central Arabian Sea, heading on a track roughly similar to that of Cyclone Chapala in the general direction of Yemen and Somalia. A tropical wave will keep moisture funneling into the Gulf of Mexico, while unusual November warmth will soon be displaced across much of the eastern U.S. by a thunderstorm-bearing cold front.
Bob Henson • 8:34 PM GMT on November 05, 2015
With only 13 fatalities reported to date, Hurricane Patricia will go down as one of the least deadly Category 5 hurricanes to make landfall in the Western Hemisphere since modern records began. Patricia’s minuscule size played a big role in the low death toll, and it also serves as a vivid contrast to the weaker but larger hurricanes that have struck the United States in recent years. It’s now been more than ten years since the U.S. has seen a major hurricane landfall (Category 3, 4, or 5). Yet the nation has incurred more than $100 billion in hurricane-related damage. Simply put, people tend to assume that a strong hurricane is also a large one, and vice versa.
Bob Henson • 3:47 PM GMT on November 04, 2015
Residents of southern Yemen are assessing the damage after Cyclone Chapala brought dramatic flooding to the region on Monday night into Tuesday. With Yemen plagued by civil war, it is difficult to know how extensive the damage from Chapala has been. Chapala was not only the second-strongest cyclone on record for the Arabian Sea, but it was also the longest-lived at Category 3 strength.
Bob Henson • 6:41 PM GMT on November 03, 2015
A stretch of Middle Eastern coastline unaccustomed to tropical cyclones of any type is about to experience a full-blown landfall, as Cyclone Chapala approaches Yemen. Catastrophic rainfall, flooding, and mudslides are possible. Meanwhile, parts of the southeast U.S. and Europe are experiencing record warmth for the month of November.
Bob Henson • 5:34 PM GMT on November 02, 2015