Hurricanes and Climate Change: Huge Dangers, Huge Unknowns

By: Dr. Jeff Masters , 9:57 AM GMT on August 05, 2013

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Hurricane Sandy's enormous $65 billion price tag put that great storm in third place for the most expensive weather-related disaster in U.S. (and world) history, and six of the ten most expensive U.S. weather-related disasters since 1980 have been hurricanes. Thus, how the strongest hurricanes may be affected due a changing climate is a topic of critical concern. Since hurricanes are heat engines that extract heat energy from the oceans to power themselves, hurricane scientists are confident that the very strongest storms will get stronger by the end of the century, when Earth's land and ocean temperatures are expected to warm 2 - 3°C, to levels unmatched since the Eemian Era, 115,000 years ago. Computer modeling work consistently indicates that greenhouse warming will cause the globally averaged intensity of tropical cyclones to shift towards stronger storms, with intensity increases of 2–11% by 2100. But hurricanes are fussy creations, and are sensitive to wind shear and dry air. Although the strongest storms should get stronger when "perfect storm" conditions are present, these "perfect storm" conditions may become less frequent in the future, due to the presence of higher wind shear, altered atmospheric circulation patterns, or more dry air at mid levels of the atmosphere. Indeed, the climate models used to formulate the 2007 IPCC report suggested that we might see the strongest hurricanes getting stronger, but a decrease in the total number of hurricanes in the Atlantic (and worldwide) later this century. However, the latest set of models used to formulate the 2013 IPCC report left open the possibility that we might see in increase in the total number of hurricanes, and and increase in their intensity. Given the conflicting model results, we really don't know how global warming will affect the number of hurricanes and their intensity, but we run the risk of making one of humanity's greatest scourges worse.


Figure 1. The list of most expensive U.S. weather-related disasters since 1980 is dominated by hurricanes.

Climate models and hurricane frequency
The database we have on historical hurricanes does not extend far enough into the past and is not of high enough quality to make many judgements on how human-caused climate change may be affecting these great storms. A landmark 2010 review paper, "Tropical Cyclones and Climate Change", authored by ten top hurricane scientists concluded that the U.S. has 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" (tropical cyclone is the generic term which encompasses tropical depressions, tropical storms, hurricanes, and typhoons.) Based in part on modeling studies using climate models run for the 2007 IPCC report, the scientists concluded that "it is likely that global mean tropical cyclone frequency will either decrease or remain unchanged owing to greenhouse warming." For example, one of the modeling studies the review paper quoted, Knutson et al. (2008), "Simulated reduction in Atlantic hurricane frequency under twenty-first-century warming conditions", projected a decrease in Atlantic tropical storms by 27% and hurricanes by 18% by the end of the century. An important reason that their model predicted these decreases was due to a predicted increase in wind shear. As I explain in my wind shear tutorial, a large change of wind speed with height over a hurricane creates a shearing force that tends to tear the storm apart. The amount of wind shear is critical in determining whether a hurricane can form or survive.

But a July 2013 study by MIT's Dr. Kerry Emanuel, "Downscaling CMIP5 climate models shows increased tropical cyclone activity over the 21st century", challenged this result. Dr. Emanuel argued that tropical cyclones are likely to become both stronger and more frequent as the climate continues to warm. This increase is most likely to occur in Western North Pacific, with smaller increases in the Atlantic. Dr. Emanuel took output from six newer higher-resolution climate models used to formulate the 2013 IPCC report, and used the output to drive a high-resolution hurricane model. The simulations found that the global frequency of tropical cyclones would increase by 11% to 40% by 2100, with intensity increases as well. The combined effects produced a global increase in Category 3 and stronger hurricanes of 40%. The behavior of these strongest hurricanes is critical, since they do most of the damage we observe. Over the past century, Category 3 - 5 hurricanes accounted for 85% of US hurricane damage, despite representing only 24% of U.S. landfalling storms. Category 4 and 5 hurricanes made up only 6% of all U.S. landfalls, but accounted for 48% of all U.S. damage (if normalized to account for increases in U.S. population and wealth, see Pielke et al., 2008.)


Figure 2. Projected changes in tropical cyclone track density during the 2006-2100 period compared to the 1950-2005 period, using output from six climate models included in the 2013 IPCC report. The global frequency of tropical cyclones is predicted to increase by 11% to 40%, with the largest changes occurring in the Northwest Pacific off the coast of Japan. Smaller increases are predicted for the Atlantic and near Australia. Image credit: Kerry Emanuel, "Downscaling CMIP5 climate models shows increased tropical cyclone activity over the 21st century", Proceedings of the National Academy of Sciences, July 8, 2013, doi: 10.1073/pnas.1301293110.

However, a study by Knutson et al. (2013), using the same latest-generation climate models as used by Emanuel (2013), but using the output from the models to drive a different high-resolution hurricane model, found a 20% decrease in Atlantic tropical storms and hurricanes by 2100. Two other 2013 studies by Villarini et al. and Camargo, also using output from the 2013 IPCC models, found essentially no change in Atlantic tropical cyclones. The reason for the differences, lies, in part, with how much global warming is assumed in the studies. Dr. Emanuel's study, which found an increase in tropical cyclone activity, assumed a worst-case warming situation (RCP 8.5), following the "business as usual" emissions path humanity is currently on. The Knutson et al. study, which found a decrease of 20% in Atlantic tropical cyclones, used a scenario (RCP 4.5) where it was assumed humans will wise up and cause about half of the worst-case greenhouse warming. The study found found "marginally significant" increases in Atlantic Category 4 and 5 hurricanes of 39% - 45% by 2100. These dramatically different results give credence to Dr. Emanuel statement at the end of his paper, "the response of tropical cyclones to projected climate change will remain uncertain for some time to come." The 2013 IPCC report also emphasized the high amount of uncertainty in how climate change might affect hurricanes, stating that there was "low confidence" that we have observed any increases in intense tropical cyclones due to human causes. However, since the 1970s, it is virtually certain (99 - 100% chance) that the frequency and intensity of hurricanes and tropical storms in the North Atlantic has increased, and there is medium confidence that a reduction in small air pollution particles (aerosols) over the North Atlantic caused part of this effect. The report's forecast for the future stated that it is "more likely than not" (50 - 100% chance) that human-caused climate change will cause a substantial increase in intense tropical cyclones in some ocean basins by 2100, with the Western North Pacific and Atlantic being at particular risk. Also, there will likely (66 - 100% chance) be an increase in both global mean tropical cyclone maximum wind speed and rain rates by 2100, and more likely than not (50 - 100% chance) that the increase in the most intense tropical cyclones will be larger than 10% in some basins.


Figure 3. Expected change in Atlantic Category 4 and 5 hurricanes per decade expected by the year 2100, according to Knutson et al. (2013), "Dynamical Downscaling Projections of 21st Century Atlantic Hurricane Activity: CMIP3 and CMIP5 Model-based Scenarios." This research used the latest generation of climate models from the 2013 IPCC report, and found "marginally significant" increases in Atlantic Category 4 and 5 hurricanes of 39% - 45% by 2100.

Commentary
Hurricane damages are currently doubling every ten years without the effect of climate change, according to Pielke et al., 2008. This is primarily due to the increasing population along the coast and increased wealth of the population. The authors theorize that the Great Miami Hurricane of 1926, a Category 4 monster that made a direct hit on Miami Beach, would have caused about $150 billion in damage had it hit in 2005. Thus, by 2015, the same hurricane would do $300 billion in damage, and $600 billion by 2025. This is without considering the impact that accelerating sea level rise will have on storm surge damages. Global sea level rise over the past decade has been about double what it was in the 20th century, and the rate of sea level rise is expected to increase further in the coming decades. Storm surge does the majority of damage in major hurricanes, and storm surges riding on top of higher sea levels are going to do a lot more damage in the coming decades. If we toss in the (controversial) increases in Category 3 and stronger storms like Dr. Emanuel suggests may occur, the hurricane damage math gets very impressive. We can also add onto that the relatively non-controversial increase in tropical cyclone rainfall of 20% expected by 2100, which will sharply increase damages due to fresh water river flooding. It is controversial whether or not we are already be seeing an increase in heavy precipitation events associated with tropical cyclones in the U.S., though. The total number of daily rainfall events exceeding 2" associated with tropical cyclones in the Southeast U.S. on a century time scale has not changed significantly, according to Groisman et al., 2004. But a 2010 study by Kunkel et al., "Recent increases in U.S. heavy precipitation associated with tropical cyclones", found that the number of Southeast U.S. tropical cyclone heavy precipitation events, defined as 1-in-5-year events, more than doubled between 1994 - 2008, compared to the long-term average from 1895 - 2008.


Figure 4. Time series of the 15-year running average (plotted at the end point of the 15-yr blocks) of a Tropical Cyclone Heavy Precipitation Index (red) and 15-year running average of U.S. landfalling hurricanes (blue). Note that there has been no long-term increase in U.S. landfalling hurricanes, but there has been a sharp increase in extreme rainfall events associated with landfalling tropical cyclones--the kind of rainfall events most likely to cause damaging flooding. Image credit: Kunkel et al. (2010), "Recent increases in U.S. heavy precipitation associated with tropical cyclones", Geophysical Research Letters.

It is essential that we limit coastal development in vulnerable coastal areas, particularly along barrier islands, to reduce some of the astronomical price tags hurricanes are going to be causing in the future. Adoption and enforcement of strict building standards is also a must, as well as more reforms to the government's National Flood Insurance Program (NFIP), which subsidizes development in high-risk coastal regions that private insurers won't touch. NFIP is now $25 - 30 billion in the red, thanks to Hurricane Katrina and Hurricane Sandy. Reform of NFIP is already underway. In 2012, before Sandy hit, Congress passed the Biggert-Waters Flood Insurance Reform Act, which requires people with NFIP policies to pay large premium increases of about 25% per year over the next five years. Naturally, this move has caused major controversy.

References
Camargo, S., (2013), "Global and regional aspects of tropical cyclone activity in the CMIP5 models," J. Climate.

Emanuel, K.A., 2013, "Downscaling CMIP5 climate models shows increased tropical cyclone activity over the 21st century", PNAS, July 8, 2013, doi: 10.1073/pnas.1301293110

Groisman, Pavel Ya, et al., "Contemporary changes of the hydrological cycle over the contiguous United States: Trends derived from in situ observations," Journal of Hydrometeorology 5.1 (2004): 64-85.

Knutson et al., 2010, "Tropical Cyclones and Climate Change", Nature Geoscience 3, 157 - 163, Published online: 21 February 2010 | doi:10.1038/ngeo779

Knutson et al., 2013, Dynamical Downscaling Projections of 21st Century Atlantic Hurricane Activity: CMIP3 and CMIP5 Model-based Scenarios, Journal of Climate 2013 ; e-View
doi: http://dx.doi.org/10.1175/JCLI-D-12-00539.1

Pielke, R.A, et al., 2008, "Normalized Hurricane Damage in the United States: 1900 - 2005," Natural Hazards Review, DOI:10.1061/ASCE1527-6988(2008)9:1(29)

Villarini, G, and G.A. Vecchi, 2012, "Twenty-first-century projections of North Atlantic tropical storms from CMIP5 models," Nature Clim. Change 2:604–607.

Related posts
Global warming and the frequency of intense Atlantic hurricanes: model results, my 2010 blog post.

Climate Central's analysis of the new 2013 Kerry Emanuel paper.

Goodbye, Miami: Jeff Goodell's sobering 2013 article in Rolling Stone on the challenges Miami faces due to sea level rise and hurricanes.


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.”

Jeff Masters

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1819. SLU
Quoting 1758. Tropicsweatherpr:


Agree with that. By the way NOAA will release their August forecast on Thursday.


My issue with NOAA is that they seem afraid to put their neck on the block and give a precise forecast. Instead, they are ultra conservative and tell you for example to expect 13 - 20 named storms, 6 - 11 hurricanes and 2 - 6 major hurricanes.
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Quoting 1732. JLPR2:


Sorry, at the moment we are heading in the opposite direction, towards a La Niña.



Congratulations on your photo making World View, #17.
Member Since: September 23, 2005 Posts: 15 Comments: 11343
Quoting 1746. RitaEvac:


That's why it'll go north to NOLA and keep us on dry windy burning up side of the storm


Thinks about it, thinks about it, Nope going to Louisiana. ;)

12z gfs ensemble

312hrs



324hrs

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Quoting 1799. bappit:

So you're going by the rocket fuel theory. The rocket may fizzle. It may just get hot and that's it.


The waters get to their warmest levels at the end of August and beginning of September. This is also when fronts start getting strong enough to drop strong lows off the tail end of them into the Gulf. It's just a matter of time IMO.
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Quoting 1803. moonlightcowboy:
Pressures falling out at Buoy Station 41040

Atmospheric Pressure: 29.92 in and falling




Of course, that's exactly standard sea level pressure,1013.25 millibars is equal to 29.92, and higher than the observed 1012mb sfc low within the surface trough embedded within the ITCZ. But, evidently it is falling. Not looking for anything to happen considering the overall environment. Certainly no model support, but stranger things have happened. ;P
Member Since: July 9, 2006 Posts: 184 Comments: 29610
1814. ackee
I think if comes next week none of the reliable models still show no real development I think we will enD up with 12 name storm or less with most Developing close to home just my view
Member Since: July 15, 2008 Posts: 0 Comments: 1376
I don't follow the exact criteria as to which factors each of the various official prediction "outlets" (CSU, NOAA, TSR, etc) consider in their forecasts, as close as some of the folks on here, but I have read that the old CSU ones from the 70's and 80's were primarily based on the Enso and Sahel/African rainfall rates. Gray noted this Saharan rainfall issue in his research papers and apparently their forecasting was pretty accurate for many years then the numbers tanked for several years. They then added additional "pre-season" criteria in recent years which can be found in their outlooks and the seem to be back on track.

The point is that as tropical meteorology continues to evolve, and computing capacity improves for prospective and analog back-years modeling and studies, we will probably see the different outlets modify and/or add or delete different criteria as they try to understand the exact mechanisms at play in order to predict the probably outcome for the next season.

However, we need to be frank. The overall "best" that we can do at the moment is the standard below average, average, or above average and folks tend to get hung up on the actual numbers.

In all honesty, if anyone in the pre-season (including the CSU's, Noaa's, Bastardi's, and Bloggers on here) actually ends up being exactly correct, at the end of the season, because the "number" of tropical storms and hurricanes they predicted occurred, it would remain an educated (hopefully) "lucky" guess at the end of the day.

Mother Nature has her own timetable and no one can predict the exact future.......All the major outlets blew the "majors" forecast last year and no one certainly predicted the explosion of storms in 2005 just to provide two examples.

Member Since: August 8, 2006 Posts: 0 Comments: 9413
Quoting 1803. moonlightcowboy:
Pressures falling out at Buoy Station 41040

Location: 14.516N 53.024W
Date: Tue, 06 Aug 2013 18:50:00 UTC
Winds: E (90°) at 11.7 kt gusting to 17.5 kt
Significant Wave Height: 5.2 ft
Dominant Wave Period: 8 sec
Mean Wave Direction: E (82°)
Atmospheric Pressure: 29.92 in and falling
Air Temperature: 79.9 F
Dew Point: 75.0 F
Water Temperature: 82.6 F



Got my eye on this wave. May have potential down the road in the Western Caribbean. IMO
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Quoting 1800. SuperStorm093:
I bet that wave doesnt intensify much, the waves that have been coming off the coast in the past 1-2 days have just faded, and the dry air wasnt an issue neither was shear.

Tell that to Dorian before unfavorable conditions got to him. Models didn't really expect formation and look what happen. Tropical cyclones can define the models odds and develop. Seen this happen many times before.
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1810. sar2401
Quoting Sfloridacat5:


Don't forget it only takes 1 storm.
Hurricane Andrew (1st storm of the season) was on Aug. 24th.
Just imagine everyone sitting around in early August 1992 with 0 storms so far in the season saying this year's a bust.

Lest we forget, 1992 also produced a June CV storm and three hurricanes after Andrew, two of which were cat 2, plus Earl, a strong TD that barely missed making landfall in Florida and the Bahamas, and TD Danielle. which made landfall in the Delmarva Peninsula. All the other storms of 1992 stayed at sea and are largely forgotten. Even though it was officially a below average season. it would have been remembered as an active season if the subsequent hurricanes and TD's would have made landfall.
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1809. nigel20
It seems as if the tropical wave will bring some wet weather the eastern Caribbean.
Member Since: November 6, 2010 Posts: 12 Comments: 8485
I wonder if we'll get any tropical-like systems in the Mediterranean Sea this year like Rolf in 2011



They seem to happen every other year since the mid 90s. :)
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1806. MrMixon
Awesome animated gif of a shower sweeping over Tokyo:



The gif was created, apparently, from this source video at Vimeo.
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Quoting 1792. Some1Has2BtheRookie:


We remember Hurricane Don. Poor little thing just evaporated as it moved ashore. Radar was saying, "Where'd it go!?!".


Oh yes. Literally got its moisture sucked out of it. Don would have had a better chance over Lake Michigan than the TX/MX coast in 2011.
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Quoting 1791. SuperStorm093:
I am not impatient, people said this week we could start to see flareup on the models, now thats pushed back to next week, I feel we are going to keep pushing it back. And the odds of seeing an Andrew this year are VERY low/

Models are doing that cause it can't really focus on the potential development but still it has hints of something. Conditions are primed and some of the other model runs so something . Patience something may spin up early next week!
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Pressures falling out at Buoy Station 41040

Location: 14.516N 53.024W
Date: Tue, 06 Aug 2013 18:50:00 UTC
Winds: E (90°) at 11.7 kt gusting to 17.5 kt
Significant Wave Height: 5.2 ft
Dominant Wave Period: 8 sec
Mean Wave Direction: E (82°)
Atmospheric Pressure: 29.92 in and falling
Air Temperature: 79.9 F
Dew Point: 75.0 F
Water Temperature: 82.6 F


Member Since: July 9, 2006 Posts: 184 Comments: 29610
While Texas is burning with more drought conditions expected meanwhile in the south east..
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Quoting 1773. Grothar:


I had the greatest links to the African continent and I lost them last year.


Did you lose them to a storm?
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I bet that wave doesnt intensify much, the waves that have been coming off the coast in the past 1-2 days have just faded, and the dry air wasnt an issue neither was shear.
Member Since: July 31, 2013 Posts: 0 Comments: 925
1799. bappit
Quoting 1796. 69Viking:


Less than a month ago the Gulf was covered in convection with multiple ULL's from Texas to Florida. Now for the last couple of weeks the Gulf has cleared which has helped warm the waters. It's only a matter of time before something tries to spin up there.

So you're going by the rocket fuel theory. The rocket may fizzle. It may just get hot and that's it.
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Quoting 1791. SuperStorm093:
I am not impatient, people said this week we could start to see flareup on the models, now thats pushed back to next week, I feel we are going to keep pushing it back.


Models are no God, they are only guidance used to help pinpoint areas of potential concern, development happens regardless of computer model support, so why even get concerned with tat stuff. Wave emerging off west Africa into the Atlantic near 10n latitude has ample opportunity to intensify and develop into a tropical cyclone. Wind shear is a low 5-10 knots, moisture is increasing around the wave, and SSTs are warm in this wave's path, it's not recurring like the Euro is saying, pattern change is coming in ten days where we head towards a ridging pattern over the eastern US and troughing over the western US. This will send storms into the SE coastline and Florida and perhaps into the Caribbean Sea and GOM.
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Quoting 1783. sar2401:

Why is the Gulf primed, especially when you're only looking at SST anomalies? Most of the Gulf has water temperatures that are average or slightly below average. Even the far western Gulf is only a little above average. As long as wee have high pressure, dry air, low vertical instability, and almost no convection, the Gulf is only primed to sit there and do nothing. I wish for the sake of Texas it was otherwise, but it is what it is.


It's in Celsius, so it's hotter than that
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Quoting 1774. sar2401:

I tend to agree. I use as my "barometer" the amount of normal convection in the Gulf for August. There are usually some convective complexes wandering around, especially near the Yucatan, to serve as a focus for storm development. We are now going on two months where not only is there not the usual convection, there's virtually no convection. There are usually one or two pre-blobs to look at but this year, there's nothing. Clearly, vertical instability is almost completely lacking. When I start seeing normal convection in the Gulf, then I'll get concerned with either a homegrown or something coming in from the Atlantic.


Less than a month ago the Gulf was covered in convection with multiple ULL's from Texas to Florida. Now for the last couple of weeks the Gulf has cleared which has helped warm the waters. It's only a matter of time before something tries to spin up there.
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Got me a tornado watch in my area this afternoon :)



URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 474
NWS STORM PREDICTION CENTER NORMAN OK
225 PM CDT TUE AUG 6 2013

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* TORNADO WATCH FOR PORTIONS OF
CENTRAL MINNESOTA
SOUTHEASTERN NORTH DAKOTA
NORTHWESTERN WISCONSIN

* EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 225 PM UNTIL
900 PM CDT.

* PRIMARY THREATS INCLUDE...
A FEW TORNADOES POSSIBLE
SEVERAL LARGE HAIL EVENTS LIKELY WITH A FEW VERY LARGE HAIL
EVENTS TO 2 INCHES IN DIAMETER POSSIBLE
SEVERAL DAMAGING WIND GUSTS TO 70 MPH LIKELY

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 80 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 45 MILES NORTH NORTHWEST OF
ORTONVILLE MINNESOTA TO 60 MILES EAST NORTHEAST OF MINNEAPOLIS
MINNESOTA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU4).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.

&&

DISCUSSION...AS A 50+ KT WESTERLY 500 MB JET STREAK CONTINUES TO
NOSE EASTWARD ACROSS THE NORTHERN PLAINS/UPPER MISSISSIPPI VALLEY
REGION LATE THIS AFTERNOON...DESTABILIZATION IS EXPECTED TO BECOME
SUFFICIENT FOR SUPERCELL DEVELOPMENT IN THE WARM SECTOR OF A WEAK
SURFACE WAVE. WITH SOME STRENGTHENING OF SOUTHERLY LOW-LEVEL FLOW
FIELDS...A REMNANT EFFECTIVE WARM FRONTAL ZONE ACROSS CENTRAL
MINNESOTA INTO THE MINNEAPOLIS AREA WILL PROVIDE A POTENTIAL FOCUS
FOR TORNADIC DEVELOPMENT THROUGH EARLY EVENING. OTHERWISE...THE
EVOLUTION OF AN ORGANIZED MESOSCALE CONVECTIVE SYSTEM MAY EVENTUALLY
OCCUR NEAR THE LOW AND ALONG A DEVELOPING COLD FRONT TRAILING TO THE
WEST...WHICH SHOULD PROPAGATE EAST SOUTHEASTWARD WITH THE RISK FOR
SEVERE WINDS AND HAIL ACROSS THE UPPER MISSISSIPPI VALLEY BY THIS
EVENING.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
450. MEAN STORM MOTION VECTOR 29035.


...KERR
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Quoting 1746. RitaEvac:


That's why it'll go north to NOLA and keep us on dry windy burning up side of the storm


Yep. Just like Lee in 2011. Worked almost three days straight cutting fire breaks. The good people of Bastrop can also thank that type of storm for their conflagration.
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1793. bappit
Quoting 1775. MAweatherboy1:
Pinhole.


Might be too big for a pin hole.
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Quoting 1739. RitaEvac:


Or vice versa...


We remember Hurricane Don. Poor little thing just evaporated as it moved ashore. Radar was saying, "Where'd it go!?!".
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I am not impatient, people said this week we could start to see flareup on the models, now thats pushed back to next week, I feel we are going to keep pushing it back. And the odds of seeing an Andrew this year are VERY low/
Member Since: July 31, 2013 Posts: 0 Comments: 925
1790. nigel20
Good afternoon all and happy independence day to everyone in Jamaica.

I did a short blog on Jamaica's independence. You can have a look if you want to. Here's the link: Happy Independence Day, Jamaica
Member Since: November 6, 2010 Posts: 12 Comments: 8485
1789. bappit
Heat! Heat! Heat!



Heat advisory:
Issued within 12 hours of the onset of the following conditions: heat index of at least 105F but less than 115F for less than 3 hours per day, or nighttime lows above 80F for 2 consecutive days.

Excessive Heat Warning
Issued within 12 hours of the onset of the following criteria: heat index of at least 105F for more than 3 hours per day for 2 consecutive days, or heat index more than 115F for any period of time.

Those definitions are from the NOAA glossary. They are a bit fuzzy, but everything seems fuzzy in the heat. I can't tell which is worse, an advisory or warning. Then the Houston-Galveston forecast discussion mentions a heat index of 108 as the magic number for issuing a heat advisory. So its been 104-107 heat index (in the shade) for a few hours every afternoon for several days now, but no heat advisory specifically for my area.

Interesting that Galveston has logged a 108 heat index with an air temp of 91. The dew point has been about 79 there.

Edit: The Tampa Bay NWS web page says to add 15F to the heat index if you are out in the sun. The table lists values for when you are in the shade.
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1788. sar2401
Quoting Grothar:
You have to love the CMC. It develops something all over, while the others do not.




Well, at least it has one of the 19 lows headed toward Texas instead of straight at me in Alabama. Hope springs eternal...:-)
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Quoting 1780. SuperStorm093:
I keep hearing a lot of talk about area's being primed, yet neither the EURO and GFS show anything over a TD. Not impressed with this season so far.


Other than 2005 hurricane season, when have you ever been impressed this early in the season, gosh people are mpatient.
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Quoting 1780. SuperStorm093:
I keep hearing a lot of talk about area's being primed, yet neither the EURO and GFS show anything over a TD. Not impressed with this season so far.


Don't forget it only takes 1 storm.
Hurricane Andrew (1st storm of the season) made landfall on Aug. 24th.
Just imagine everyone sitting around in early August 1992 with 0 storms so far in the season saying this year's a bust.
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1785. Grothar
Quoting 1779. seer2012:
sat24.com has a really good late afternoon piture of what is there.


There was one I could post.


Link
Member Since: July 17, 2009 Posts: 71 Comments: 27210
Quoting 1780. SuperStorm093:
I keep hearing a lot of talk about area's being primed, yet neither the EURO and GFS show anything over a TD. Not impressed with this season so far.

Oh, it won't be long till you are impressed trust me it's about to blow up very very soon!
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1783. sar2401
Quoting RitaEvac:
Gulf primed


Why is the Gulf primed, especially when you're only looking at SST anomalies? Most of the Gulf has water temperatures that are average or slightly below average. Even the far western Gulf is only a little above average. As long as wee have high pressure, dry air, low vertical instability, and almost no convection, the Gulf is only primed to sit there and do nothing. I wish for the sake of Texas it was otherwise, but it is what it is.
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Quoting 1775. MAweatherboy1:
Pinhole.



Damn, that's an impressive inner core.

The wave emerging off the coast of west Africa could become Erin in the next 48 hours, I give it a chance of 20% and 30%in five days.
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I keep hearing a lot of talk about area's being primed, yet neither the EURO and GFS show anything over a TD. Not impressed with this season so far.
Member Since: July 31, 2013 Posts: 0 Comments: 925
sat24.com has a really good late afternoon piture of what is there.
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Quoting 1764. Grothar:
You have to love the CMC. It develops something all over, while the others do not.



LOL that is like a season's worth of the Tropical Storms and Hurricanes. :D
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Quoting 1767. washingtonian115:
LOL.I'm being sarcastic.What I'm really meaning to say is that I don't care for the east pacific :).

Same here. Unless some bad storm there was heading toward land there, I couldn't care less about what forms there.
The only time I care, is when energy transfers into the Atlantic and forms. lol (Arthur, Hermine, etc.)
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Gulf primed

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Pinhole.

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1774. sar2401
Quoting StormTrackerScott:


To be honest I don't see any storms getting anywhere close to the Western Gulf based on the current set up.

Fairly strong trough setting up shop across the Ohio Valley. Bad set up for FL and the coastal SE US.


I tend to agree. I use as my "barometer" the amount of normal convection in the Gulf for August. There are usually some convective complexes wandering around, especially near the Yucatan, to serve as a focus for storm development. We are now going on two months where not only is there not the usual convection, there's virtually no convection. There are usually one or two pre-blobs to look at but this year, there's nothing. Clearly, vertical instability is almost completely lacking. When I start seeing normal convection in the Gulf, then I'll get concerned with either a homegrown or something coming in from the Atlantic.
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1773. Grothar
Quoting 1763. seer2012:

That area over Niger and Mali looks really strong. It has some thunderstorms that are fairly large.


I had the greatest links to the African continent and I lost them last year.
Member Since: July 17, 2009 Posts: 71 Comments: 27210
Quoting 1767. washingtonian115:
LOL.I'm being sarcastic.What I'm really meaning to say is that I don't care for the east pacific :).

XD wow my brain is turned off today
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Quoting 1770. wunderweatherman123:
no caleb there was another one you showed. it looked much stronger
that was the 850 mb winds, so those wouldnt reach the surface, its a 55-60 mph TS.
Member Since: July 31, 2013 Posts: 0 Comments: 925
Quoting 1760. GTstormChaserCaleb:
60 mph on the 10 meter wind field.

no caleb there was another one you showed. it looked much stronger
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Henriette becoming well-organized. A compact eye feature is visible on latest satellite imagery and 18z satellite estimates from TAFB and SAB yield an intensity of 77kts. ADT on the other hand is far more impressed indicating an intensity of about 85kts. Based on this data, it would appear to me that Henriette is easily an 80kt hurricane that continues to intensify.

2013AUG06 183000 4.8 975.2 84.8 4.8 4.8 4.4 MW ON OFF OFF -64.76 -68.43 EMBC N/A 23.9 14.48 132.02 SPRL GOES15 17.3

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