Are tornadoes getting stronger and more frequent?

By: Dr. Jeff Masters , 4:24 PM GMT on February 26, 2008

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Are tornadoes and severe thunderstorms getting more numerous and more extreme due to climate change? To help answer this question, let's restrict our attention to the U.S., which has the highest incidence of tornadoes and severe thunderstorms of any place in the world. At a first glance, it appears that tornado frequency has increased in recent decades (Figure 1).


Figure 1. The number of EF-0 (blue line) and EF-1 and stronger tornadoes (maroon diamonds) reported in the U.S. since 1950. There is not a decades-long increasing trend in the numbers of tornadoes stronger than EF-0, implying that climate change, as yet, is not having a noticeable impact on U.S. tornadoes. However, statistics of tornado frequency and intensity are highly uncertain. Major changes in the rating process occurred in the mid-1970s (when all tornadoes occurring prior to about 1975 were retrospectively rated), and again in 2001, when scientists began rating tornadoes lower because of engineering concerns and unintended consequences of National Weather Service policy changes. According to Brooks (2013), "Tornadoes in the early part of the official National Weather Service record (1950-approximately 1975) are rated with higher ratings than the 1975 - 2000 period, which, in turn, had higher ratings than 2001 - 2007." Also, beginning in 2007, NOAA switched from the F-scale to the EF-scale for rating tornado damage, causing additional problems with attempting to assess if tornadoes are changing over time. Image credit: Kunkel, Kenneth E., et al., 2013, "Monitoring and Understanding Trends in Extreme Storms: State of Knowledge," Bull. Amer. Meteor. Soc., 94, 499–514, doi: http://dx.doi.org/10.1175/BAMS-D-11-00262.1

However, this increase may be entirely caused by factors unrelated to climate change:

1) Population growth has resulted in more tornadoes being reported.

2) Advances in weather radar, particularly the deployment of about 100 Doppler radars across the U.S. in the mid-1990s, has resulted in a much higher tornado detection rate.

3) Tornado damage surveys have grown more sophisticated over the years. For example, we now commonly classify multiple tornadoes along a damage path that might have been attributed to just one twister in the past.

Given these uncertainties in the tornado data base, it is unknown how the frequency of tornadoes might be changing over time. The "official word" on climate science, the 2007 United Nations IPCC report, stated it thusly: "There is insufficient evidence to determine whether trends exist in small scale phenomena such as tornadoes, hail, lighting, and dust storms." Furthermore, we're not likely to be able to develop methods to improve the situation in the near future.The current Doppler radar system can only detect the presence of a parent rotating thunderstorm that often, but not always, produces a tornado. Until a technology is developed that can reliably detect all tornadoes, there is no hope of determining how tornadoes might be changing in response to a changing climate. According to Doswell (2007): I see no near-term solution to the problem of detecting detailed spatial and temporal trends in the occurrence of tornadoes by using the observed data in its current form or in any form likely to evolve in the near future.

Are strong tornadoes increasing?
Stronger tornadoes (greater than EF-0 on the Enhanced Fujita Scale, or F0 on the pre-2007 Fujita Scale) are more likely to get counted, since they tend to cause significant damage along a long track. Thus, the climatology of these tornadoes may offer a clue as to how climate change may be affecting severe weather. Unfortunately, we cannot measure the wind speeds of a tornado directly, except in very rare cases when researchers happen to be present with sophisticated research equipment. Tornadoes are categorized using the Enhanced Fujita (EF) scale, which is based on damage (note that the EF scale to rate tornadoes was adopted in 2007, but the transition to this new scale still allows valid comparisons of tornadoes rated, for example, EF-5 on the new scale and F-5 on the old scale.) So, if a strong tornado happens to sweep through empty fields and never destroy any structures, it will never be rated as a strong tornado. Thus, if the number of strong tornadoes has actually remained constant over the years, we should expect to see some increase in these twisters over the decades, since more buildings have been erected in the paths of tornadoes. However, if we look at the statistics of U.S. tornadoes stronger than EF-0 or F-0 since 1950, there does not appear to be any increase in their number. Not surprisingly, a study accepted for publication in Environmental Hazards (Simmons et al., 2012) found no increase in tornado damages from 1950 - 2011, after normalizing the data for increases in wealth and property (note, though, that I am suspicious of studies that normalize disaster data, since they are prone to error, as revealed by a 2012 study looking at storm surge heights and damages.)

The future of tornadoes
An alternate technique to study how climate change may be affecting tornadoes is look at how the large-scale environmental conditions favorable for tornado formation have changed through time. Moisture, instability, lift, and wind shear are needed for tornadic thunderstorms to form. The exact mix required varies considerably depending upon the situation, and is not well understood. However, Brooks (2003) attempted to develop a climatology of weather conditions conducive for tornado formation by looking at atmospheric instability (as measured by the Convective Available Potential Energy, or CAPE), and the amount of wind shear between the surface and 6 km altitude. High values of CAPE and surface to 6 km wind shear are conducive to formation of tornadic thunderstorms. The regions they analyzed with high CAPE and high shear for the period 1997-1999 did correspond pretty well with regions where significant (F2 and stronger) tornadoes occurred. The authors plan to extend the climatology back in time to see how climate change may have changed the large-scale conditions conducive for tornado formation. Riemann-Campe et al. (2009) found that globally, CAPE increased significantly between 1958 - 2001. However, little change in CAPE was found over the Central and Eastern U.S. during spring and summer during the most recent period they studied, 1979 - 2001. A preliminary report issued by NOAA’s Climate Attribution Rapid Response Team in July 2011 found no trends in CAPE or wind shear over the lower Mississippi Valley over the past 30 years. However, preliminary work by J. Sander of Munich Re insurance company, presented at the December 2011 American Geophysical Union meeting in San Francisco, found that the number of days with very high CAPE values over the eastern two-thirds of the United States between 1970 and 2009 did increase significantly.

Del Genio et al.(2007) used a climate model with doubled CO2 to show that a warming climate would make the atmosphere more unstable (higher CAPE) and thus prone to more severe weather. However, decreases in wind shear offset this effect, resulting in little change in the amount of severe weather in the Central and Eastern U.S. late this century. The speed of updrafts in thunderstorms over land increased by about 1 m/s in their simulation, though, since upward moving air needed to travel 50-70 mb higher to reach the freezing level. As a result, the most severe thunderstorms got stronger. In the Western U.S., the simulation showed that drying led lead to fewer thunderstorms, but the strongest thunderstorms increased in number by 26%, leading to a 6% increase in the total amount of lighting hitting the ground each year. If these results are correct, we might expect more lightning-caused fires in the Western U.S. late this century, due to enhanced drying and more lightning.

Using a high-resolution regional climate model (25 km grid size) zoomed in on the U.S., Trapp et al. (2007) and Trapp et al. (2009) found that the decrease in 0-6 km wind shear in the late 21st century would more than be made up for by an increase in instability (CAPE). Their model predicted an increase in the number of days with high severe storm potential for almost the entire U.S., by the end of the 21st century. These increases were particularly high for many locations in the Eastern and Southern U.S., including Atlanta, New York City, and Dallas (Figure 3). Cities further north and west such as Chicago saw a smaller increase in the number of severe weather days.


Figure 3. Number of days per year with high severe storm potential historically (blue bars) and as predicted by the climate model (A2 scenario) of Trapp et al. 2007 (red bars).

Summary
We currently do not know how tornadoes and severe thunderstorms may be changing due to changes in the climate, nor is there hope that we will be able to do so in the foreseeable future. At this time, it does not appear that there has been an increase in U.S. tornadoes stronger than EF-0 in recent decades. Preliminary research using climate models suggests that we may see an increase in the number of severe storms capable of producing tornadoes over the U.S. late this century. However, this research is just beginning, and much more study is needed to confirm these findings.

References
Brooks, H.E., 2013, "Severe thunderstorms and climate change," Atmospheric Research, Volume 123, 1 April 2013, Pages 129–138, http://dx.doi.org/10.1016/j.atmosres.2012.04.002.

Brooks, H.E., J.W. Lee, and J.P. Craven, 2003, "The spatial distribution of severe thunderstorm and tornado environments from global reanalysis data", Atmospheric Research Volumes 67-68, July-September 2003, Pages 73-94.

Doswell, C.A., 2007, "Small Sample Size and Data Quality Issues Illustrated Using Tornado Occurrence Data", E-Journal of Severe Storms Meteorology Vol 2, No. 5 (2007).

Del Genio, A.D., M-S Yao, and J. Jonas, 2007,
Will moist convection be stronger in a warmer climate?, Geophysical Research Letters, 34, L16703, doi: 10.1029/2007GL030525.

Kunkel, Kenneth E., et al., 2013, "Monitoring and Understanding Trends in Extreme Storms: State of Knowledge," Bull. Amer. Meteor. Soc., 94, 499–514, doi: http://dx.doi.org/10.1175/BAMS-D-11-00262.1

Marsh, P.T., H.E. Brooks, and D.J. Karoly, 2007, Assessment of the severe weather environment in North America simulated by a global climate model, Atmospheric Science Letters, 8, 100-106, doi: 10.1002/asl.159.

Riemann-Campe, K., Fraedrich, K., and F. Lunkeit, 2009, Global climatology of Convective Available Potential Energy (CAPE) and Convective Inhibition (CIN) in ERA-40 reanalysis, Atmospheric Research Volume 93, Issues 1-3, July 2009, Pages 534-545, 4th European Conference on Severe Storms.

Simmons, K.M., Dutter, D., and Pielke, R., 2012, "Normalized Tornado Damage in the United States: 1950-2011," DOI: 10.1080/17477891.2012.738642

Trapp, R.J., N.S. Diffenbaugh, H.E. Brooks, M.E. Baldwin, E.D. Robinson, and J.S. Pal, 2007, Severe thunderstorm environment frequency during the 21st century caused by anthropogenically enhanced global radiative forcing, PNAS 104 no. 50, 19719-19723, Dec. 11, 2007.

Trapp, R. J., Diffenbaugh, N. S., & Gluhovsky, A., 2009, "Transient response of severe thunderstorm forcing to elevated greenhouse gas concentrations," Geophysical Research Letters, 36(1).

Jeff Masters

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143. weathers4me
1:02 AM GMT on February 28, 2008
Thank you weather456. Much appreciated.
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142. Weather456
8:48 PM AST on February 27, 2008
139. weathers4me 8:18 PM AST on February 27, 2008
ok I promised my son I would ask the weather experts on underground. He missed a question on his science class in weather. The questions reads: What might happen when two air masses come together and form a warm front? answers A. steady rain B. thunderstorms C. a strong sea breeze and D. cooler temperatures. He answered B. thunderstorms and got it wrong. What do you think? Thanks


stratiform clouds are assoicated with warm fronts due to the front's gentle slope. Stratiform clouds produce steady rain. Cant be thunderstorms (not impossible) but warm fronts are not as convectively unstable as cold fronts.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
139. weathers4me
12:14 AM GMT on February 28, 2008
ok I promised my son I would ask the weather experts on underground. He missed a question on his science class in weather. The questions reads: What might happen when two air masses come together and form a warm front? answers A. steady rain B. thunderstorms C. a strong sea breeze and D. cooler temperatures. He answered B. thunderstorms and got it wrong. What do you think? Thanks
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138. Weather456
8:02 PM AST on February 27, 2008
with all that upwelling along the Pacifc coast of central america, i wonder how early thier season will start. tho ssts can rebound in a matter of weeks
Member Since: July 24, 2005 Posts: 407 Comments: 19076
137. Weather456
7:43 PM AST on February 27, 2008
Follow up to this morning's synopsis

As the cold front exists the region, the associated high pressure continues to build across the Deep South producing moderate to strong offshore flow. This flow is assoicated with 20-35 knot north winds and 14-18 ft swells which are forecast to continue to push behind the front as it progresses southeastward.

I just checked some of the buoys out there and the winds and seas have subsided across the Western Gulf. Buoy 42002 in the western Gulf of Mexico has passed its peak today when it reported 13-14 ft seas and 29 knot sustain winds G 36 knots early this morning around 4-5 am. The bulk of the wave action has now moved into the central and Eastern Gulf as seen with buoy 42003 further east of afformentioned buoy.





Buoy 42001 in the central gulf


The Gulf of Tehuantepec is also experiencing another storm force event. This is about the 3rd for the year and the 4th for the winter season (December-April).



Member Since: July 24, 2005 Posts: 407 Comments: 19076
136. NorthxCakalaky
11:55 PM GMT on February 27, 2008
North Carolina
More snow totals in.(Still another 5hours of heavy snow likely) From weatherunderground

... Avery County...
Beech Mountain 5.0 730 am 2/27 12 deg at 7 am
Elk Park 5.0 230 PM 2/27
Seven Devils 4.0 1149 am 2/27
Flat Springs 3.0 700 am 2/27 1.2 E Flat Springs
Minneapolis 3.0 225 PM 2/27
Newland 1.0 215 PM 2/27 Avery comms center

... Buncombe County...
Weaverville 3.0 700 am 2/27 4.7 NNW Weaverville
Asheville 1.0 110 PM 2/27
Asheville recreation 1.0 700 am 2/27 5.7 NNW Asheville
Enka 1.0 800 am 2/27
Swannanoa 1.0 800 am 2/27 2 S Swannanoa
Fairview T 700 am 2/27 3.8 ENE Fairview

... Graham County...
Robbinsville 9.0 930 am 2/27 9 W Robbinsville
Robbinsville 5.0 700 am 2/27 1.3 S Robbinsville
Robbinsville 4.0 930 am 2/27

... Haywood County...
Waynesville 7.0 155 PM 2/27 17 NE Waynesville
Waterville 5.0 130 PM 2/27 1 SW Waterville Lake
Maggie Valley 3.0 100 PM 2/27 4 NE Maggie Valley
Waynesville 3.0 110 PM 2/27 10 N waynesville3000ft
Maggie Valley 1.0 1230 PM 2/27 Post office report
Waynesville 0.5 1246 PM 2/27 pubic report

... Jackson County...
Dillsboro 0.5 700 am 2/27 6 NW Dillsboro
Sylva T 1117 am 2/27

... Macon County...
Franklin T 700 am 2/27 7.3 E Franklin

... Madison County...
Hot Springs 4.0 730 am 2/27
Marshall 4.0 730 am 2/27

... Mitchell County...
Buladean 8.0 215 PM 2/27 11 NNW Bakersville
Spruce Pine 2.0 730 am 2/27

... Swain County...
Newfound Gap 12.0 730 am 2/27 at 5000 feet
oconaluftee 1.0 700 am 2/27
Bryson City T 800 am 2/27

... Yancey County...
Burnsville 4.0 210 PM 2/27 9 NW Burnsville
Mount Mitchell 3.0 700 am 2/27 6 degrees at 7 am
Burnsville 2.0 700 am 2/27 4.6 N Burnsville


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135. NorthxCakalaky
11:28 PM GMT on February 27, 2008
North Carolina

... Alleghany County...
Laurel Springs T 545 PM 2/27

... Ashe County...
Fleetwood 5.5 545 PM 2/27

... Watauga County...
Rominger 8.0 600 PM 2/27 Beech Mountain
Peoria 7.5 600 PM 2/27
Silverstone 7.5 600 PM 2/27 along Rich Mountain
Zionville 7.5 600 PM 2/27
Boone 3.5 600 PM 2/27


Snow should end by 1:00p.m Thursday here in N.C.Reports of white-outs and like blizzard like conditions.The highest elevations in N.C, slightly below 6000f.t got around and over 20inches.(Officaly 17 about 5hours ago)
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134. hondaguy
9:36 PM GMT on February 27, 2008
110. Greyelf 6:58 PM GMT on February 27, 2008
Ok, I'm trying this one last time since my last post was either lost or removed. I wanted to thank Patrap and Caffinehog for being the only two people to take the time out of their busy lives to answer my question. To the rest of you - keep your clique. I'm tired of trying to make a dent into your exclusive club. At the very least, I figured someone would say "Go away, this isn't on topic. Here's where to go to bother them with your question." I know I have never posted much here, but have from time to time - mostly ignored then too. I'm done.


I read your question and to answer it: Your best bet is to keep an eye on the 10 day forecast. Though this is constantly revised and could change it's about the most accurate thing you could go by.

That and check wunderground vs weather.com, and other sites that you could compare forecasts to.

In your heated response I think you forgot to mention StormW that had answered your question also *before* you posted the comment above.

Like many people said they simply just do not know the answer to your question. I know I sure dont. Just watch the 10 day, and if I were you I'd take the southern route.

You risk running into icy conditions on the northern route that time of year. Of course if it's still abnormally cold in the Kentucky area you risk ice there as well.

Best of luck to you in any case.

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133. BahaHurican
4:43 PM EST on February 27, 2008
STL, this still is all on the COAST as compared to WY, and UT. I'm going to check some records right now.
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132. BahaHurican
4:25 PM EST on February 27, 2008
129. trunkmonkey 4:18 PM EST on February 27, 2008
123. BahaHurican 8:49 PM GMT on February 27, 2008
121. MichaelSTL 3:42 PM EST on February 27, 2008

We better hope that this isn't right, or a near-Biblical drought and heat wave will scorch virtually the entire U.S. this summer;

WOW!! And places like Wyoming and Utah had really dry summers in 2007, with reservoir levels at their lowest in ages. If this eventuates, things are going to be even worse for the intermountain West.

WOW!! the west has had more moisture, snow and rain, than they have had in the past 80 years, snow depths are at record highs. Just the fax, just the fax!


I'm going to have to check stats, but I don't think WY has got the same kind of precip this winter as other areas, particularly to the NW and south of it. Something about a rain shadow thing. A lot of water that drains through Utah to the Colorado originates in WY.

I'll see if I can find precip for WY for the last three months.

Yeah, I coulda left off the WOW!

LOL
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130. CJ5
9:29 PM GMT on February 27, 2008
Hello all...just checking in. I was wondering if the ghost of Ingrid is still out there..lol
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129. trunkmonkey
9:16 PM GMT on February 27, 2008
123. BahaHurican 8:49 PM GMT on February 27, 2008
121. MichaelSTL 3:42 PM EST on February 27, 2008

We better hope that this isn't right, or a near-Biblical drought and heat wave will scorch virtually the entire U.S. this summer;

WOW!! And places like Wyoming and Utah had really dry summers in 2007, with reservoir levels at their lowest in ages. If this eventuates, things are going to be even worse for the intermountain West.

WOW!! the west has had more moisture, snow and rain, than they have had in the past 80 years, snow depths are at record highs. Just the fax, just the fax!
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128. Weather456
5:02 PM AST on February 27, 2008
119. BahaHurican 4:35 PM AST on February 27, 2008
Afternoon everybody.

I thought the blog header was really interesting today. One question, though:

Why is the US particularly vulnerable to tornados? I keep wondering why they aren't also common in places like China, Australia, and sub-equatorial Africa.


I also use to wonder then a few years I discover something. Geography (location and physiograhy) played a major role. The flat open land of the great plains lies between three major airmassess. The Dry Continental tropical airmass of the mountains to the west, the warm moist tropical airmass to the south and he contintental polar airmasses to the north. Where else in the world on such a large scale (synoptic scale) a low level jets transport warm moist air at low levels from the gulf, while westerlies transport dry air from the mountains which is equivalent to the mid-levels of lower plains to the east. And along with that, the famous jet streams at 200 mb. This creates a very unstable situation, where u have mid level dry air above warm moist air. All u need now is lifting mechanism and there are several ways in which that moist air can rise and a cold front is major one. Then the jet provides the necessary spin.

The other place I wud say comes close to that is Australia but is there isnt enough lifting over the desert.

Sometimes I wonder how cud a place so perfectly fit all the neccessary conditions of tornado formation just by geography alone. I guess u guys are bad lucky.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
127. atmoaggie
9:07 PM GMT on February 27, 2008
110. Greyelf 6:58 PM GMT on February 27, 2008
Ok, I'm trying this one last time since my last post was either lost or removed. I wanted to thank Patrap and Caffinehog for being the only two people to take the time out of their busy lives to answer my question. To the rest of you - keep your clique. I'm tired of trying to make a dent into your exclusive club. At the very least, I figured someone would say "Go away, this isn't on topic. Here's where to go to bother them with your question." I know I have never posted much here, but have from time to time - mostly ignored then too. I'm done.


Wow. I had no a idea that a "I do not know of any resource I would trust with a very long range forecast with a lot on money on the line" comment would have made anyone so warm and fuzzy. I guess we should all fill the page with "I dunno" every time a question is aksed from here on out. Of course a real answer might be buried in there somewhere, but c'est la vie. Better that than to have someone think we are really that cliqueish.
Member Since: August 16, 2007 Posts: 6 Comments: 12461
126. NEwxguy
9:06 PM GMT on February 27, 2008
STL,then I guess I better hope for alot more rain,and get the resevoirs to the top.
Thats not good news for the summer
Member Since: September 6, 2007 Posts: 874 Comments: 15580
125. weatherboykris
9:05 PM GMT on February 27, 2008
I'm somewhat surprised that there wasn't an "other" option.
Member Since: December 9, 2006 Posts: 125 Comments: 11346
124. weatherboykris
9:03 PM GMT on February 27, 2008
I see what you're saying STL.I could even see how many people would enjoy the warmer temps,during the winter at least.Who dislikes 70 degrees in January?
Member Since: December 9, 2006 Posts: 125 Comments: 11346
123. BahaHurican
3:45 PM EST on February 27, 2008
121. MichaelSTL 3:42 PM EST on February 27, 2008

We better hope that this isn't right, or a near-Biblical drought and heat wave will scorch virtually the entire U.S. this summer;


WOW!! And places like Wyoming and Utah had really dry summers in 2007, with reservoir levels at their lowest in ages. If this eventuates, things are going to be even worse for the intermountain West.
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122. BahaHurican
3:35 PM EST on February 27, 2008
I'm not surprised the sea level rise was also a popular choice. With populations near seacoasts increasing, more people are likely to be impacted. And in low-lying areas like the Bahamas and Florida, even a 1-foot increase can have detrimental effects.
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120. Levi32
11:36 AM AKST on February 27, 2008
Severe weather isn't quite my top game.....but I do know the US has a very unique set up for tornadoes. The cold air in Canada combined with the warm-moist air from the Gulf of Mexico really enhance lows moving across the US...and provide all the ingredients necessary for severe weather. Also the jet-stream is usually in quite a favorable position over the southern states. Other places in the world don't have quite this perfect set-up of different airmass sources, and some that do aren't quite at the right latitude or location in the upper-air flow. In southern Asia the Bay of Bengal sometimes acts like the Gulf of Mexico and fuels severe storms in that area....but no location is quite as "perfect" as tornado alley here in the U.S.
Member Since: November 24, 2005 Posts: 635 Comments: 26547
119. BahaHurican
3:30 PM EST on February 27, 2008
Afternoon everybody.

I thought the blog header was really interesting today. One question, though:

Why is the US particularly vulnerable to tornados? I keep wondering why they aren't also common in places like China, Australia, and sub-equatorial Africa.
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117. BahaHurican
3:10 PM EST on February 27, 2008
110. Greyelf 1:58 PM EST on February 27, 2008
Ok, I'm trying this one last time since my last post was either lost or removed. I wanted to thank Patrap and Caffinehog for being the only two people to take the time out of their busy lives to answer my question. To the rest of you - keep your clique. I'm tired of trying to make a dent into your exclusive club. At the very least, I figured someone would say "Go away, this isn't on topic. Here's where to go to bother them with your question." I know I have never posted much here, but have from time to time - mostly ignored then too. I'm done.


I only want to know what I was supposed to have posted when I DON'T KNOW THE ANSWERS TO ANY OF THE QUESTIONS!!!!! Some of us actually don't post if we don't know what the $#@% we are talking about.

OTOH, If u had asked about driving a car from the Bahamas, I may have been able to help you.

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116. NEwxguy
8:29 PM GMT on February 27, 2008
no worries of drought here in the northeast:

...RECORD FEBRUARY PRECIPITATION FOR BOSTON...

WITH THE RAINFALL TOTAL OF 0.39 INCHES AT BOSTONS LOGAN
INTERNATIONAL AIRPORT ON TUESDAY...A RECORD MONTHLY PRECIPITATION
RECORD HAS BEEN SET FOR FEBRUARY. THE MONTHLY PRECIPITATION TOTAL
SO FAR FOR FEBRUARY 2008 IS 7.86 INCHES.

THE PREVIOUS RECORD WAS 7.81 INCHES SET IN FEBRUARY 1984.

WEATHER RECORDS IN BOSTON DATE BACK TO 1872.

Member Since: September 6, 2007 Posts: 874 Comments: 15580
115. Levi32
11:28 AM AKST on February 27, 2008
Lol...warmer temperatures are the cause for all the other choices on the poll...so everyone got specific lol
Member Since: November 24, 2005 Posts: 635 Comments: 26547
114. NEwxguy
8:19 PM GMT on February 27, 2008
Looking into next week,it looks like there may be some very beneficial rains for the drought stricken SE,here's hoping for you people that it happens.
Member Since: September 6, 2007 Posts: 874 Comments: 15580
113. weatherboykris
8:12 PM GMT on February 27, 2008
Funny results from the Wunderpoll.Only 6 percent were most concerned about warmer temperatures,LOL.
Member Since: December 9, 2006 Posts: 125 Comments: 11346
112. counters
7:46 PM GMT on February 27, 2008
Haarp, off the top of my head, I don't know of any of the type of resource that you want to find, but I'd bve interested in finding it as well. I can tell you, though, that meteorologists take into account cities when they forecast; essentially, a city acts like a hill and causes orographic lifting, leading to enhanced precipitation and other phenomenon. I'm not aware of any upper atmosphere disturbances that cities have been documented as the cause of, though.
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111. HAARP
7:10 PM GMT on February 27, 2008
another reason that I would think is that as cities grow bigger and hotter they would disrupt the normal weather patterns causing disturbances in the upper atmosphere and other places...the increased building amounts may also change surface patters as there is more surface disturbances ...

Is there a reason these things dont get looked into or reported?

I would love to see a frequency MAP of these patterns and to see WHERE increases took place. Is there anywhere to find that?

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110. Greyelf
12:53 PM CST on February 27, 2008
Ok, I'm trying this one last time since my last post was either lost or removed. I wanted to thank Patrap and Caffinehog for being the only two people to take the time out of their busy lives to answer my question. To the rest of you - keep your clique. I'm tired of trying to make a dent into your exclusive club. At the very least, I figured someone would say "Go away, this isn't on topic. Here's where to go to bother them with your question." I know I have never posted much here, but have from time to time - mostly ignored then too. I'm done.
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109. Weather456
12:36 PM AST on February 27, 2008
Democrat Vs Democrat
Member Since: July 24, 2005 Posts: 407 Comments: 19076
108. Weather456
12:00 PM AST on February 27, 2008
99. JFV 9:11 AM AST on February 27, 2008
Good Wednesday morning all!!! Hey Weather456, arent't those in-depth Atlantic Ocean weather discussions only valid during hurricane season?


no..i do them year round

102. StormW 9:45 AM AST on February 27, 2008
99. JFV 8:11 AM EST on February 27, 2008
Good Wednesday morning all!!! Hey Weather456, arent't those in-depth Atlantic Ocean weather discussions only valid during hurricane season?

Think of it kinda like 456 carrying on where I left off...during hurricane season when I post my tropical forecast, I will analyze a lot of different maps, and in my discussion will post items on the MJO, SOI, wind shear, where the TUTT(s) are located, approximation of tropical waves, etc.


Nope....i also analyse the tropics (TUTTS, ENSO, Teleconnections, the monsoon trof, etc) during the hurricane season. I only started posting them here during the off season when there is less traffic on the blog.

For example: Aug 13 2007

special tropical/subtropical systems....

an upper low is centred near 27n/91w. showers continue in the southeastern gulf of mexico where the upper level low interacting with a tropical wave along 86w. surface observations continue to indicate a broad area of low pressure centred on 1007 millibar low near 23n/83w. observation also indicate 20-25 knots which is in fair agreement with the current t numbers from ssd. sea surface temperatures are more than favourable to support development but 20-30 knots of shear is impeding development but is forecast to become more favourable. current forecast track is to head west-northwest towards central mexico/texas.

tropical depression four is centred near 12.0n/34.2w moving west near 17 knots as of 0145 utc. despite increase curve banding features with this system., the centre of circulation remains the eastern edge of the deep convective mass as some easterly shear continues to affect it. conditions still are forecast to become more favourable for additional organization and a tropical storm could form in next 12 hrs. dvorak t numbers have not change and remain at 2.0 or 30 knots. i don't think the forecast track will change much from 5 pm and the leeward islands still should closing monitor it.


and....

Excert from Sep 1 2006

As of 8amAST, Tropical Storm Florence was located at 24.4N/63.3W, moving WNW near 14mph. The storm is packing winds of 65mph and a MCP of 993mbars.

Florence has gain increased organization in the overnights and continues to organize at this moment. This morning visible imagery revealed banding developing in almost all quadrants and substantial outflow in the Eastern Semicircle of Florence's cloud canopy.
The center of Florence (which was also exposed 24hrs ago), is now located in a tightly, well define CDO (Central Dense Overcast).

According to 85H Brightness Temperature Imagery from the Navy, Florence appears to be forming an eye-wall, and could become a hurricane later today or on Sunday.

Member Since: July 24, 2005 Posts: 407 Comments: 19076
104. Patrap
8:35 AM CST on February 27, 2008
May 4th 2007 Greensburg Kansas Tornado. Incredible footage of the EF-5 tornado up close. Sean Wilson of Blown Away Tours along with Tim Andrews video taped this monster as they were traveling down hwy 183 with debris falling all around. Get ready for this wild ride.

Link
Member Since: July 3, 2005 Posts: 420 Comments: 127536
103. Patrap
8:27 AM CST on February 27, 2008
5 years ago...this question was being researched.
I say lets expand the debate and target 2012,June 1 for a new One.


2003 Seattle Annual Meeting (November 2, 2003)
Paper No. 180-9
Presentation Time: 3:30 PM-3:45 PM
A NEW HURRICANE COASTAL IMPACT SCALE,CONTINUED WORK

Link

The ultimate goal of the proposed HIS is a tool for hurricane/weather forecasters to give coastal residents more information for preparing for a storms potential impact. As an example, Hurricane Andrew (1992) was one of the strongest storms on record (SSS category 4) but it was also a relatively small storm. Opal (1995) was a weaker storm (category 3) but it was much larger. Although Andrew caused a tremendous amount of inland wind damage, Opal actually caused more shoreline erosion and overwash. The HIS rankings reflect this (Andrew-8, Opal-11). Inclusion of the SSS in the HIS reflects the critical nature of storm strength in any such scale. Two storm surge parameters are justified because storm surge is the best measure of a hurricanes energy flux at the shoreline, and thus the potential for erosion, overwash, and property damage at and near the shore.

Member Since: July 3, 2005 Posts: 420 Comments: 127536
101. surfmom
1:33 PM GMT on February 27, 2008
weather456 - nice review - I am not looking forward to working horses out on a track in this windy weather - promises to be a "dicey" morning. The unexpected strong gusts are great for blowing stuff around (palms, leaves..and the very worst plastic bags --most horses will swear a plastic bag can eat them)Was up on and off all night due to the wind - some very strong gusts 25mph. The Gulf must be rocking because I can hear from my house - not usual. Well I am off to work - definitely a day to wear my brain bucket - helmet, just in case - someone decides to spook.
Member Since: July 18, 2007 Posts: 30 Comments: 26536
100. Patrap
7:13 AM CST on February 27, 2008
Weather happens 365/24/7 for Marine Interest's
Member Since: July 3, 2005 Posts: 420 Comments: 127536
97. lilmax
12:42 PM GMT on February 27, 2008
Good morning. Whew, close call with the storms last night. I don't think I'll like the lows of 43 degrees with windchills of 36 degrees tonight. Too cold for SoFlo.
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96. Weather456
7:21 AM AST on February 27, 2008
Good Wednesday Morning to all:

6:56 AM AST WEDNESDAY, FEBRUARY 27, 2008

GULF OF MEXICO/NORTHWEST ATLANTIC OCEAN WEST OF 50W....

An upper trough is situated over the Eastern half of the CONUS with the associated cold front pushing across the Gulf Mexico from the Tabasco Plain in the Southern Bay of Campeche to the Florida Peninsula and beyond. The front lies within a southwesterly upper flow regime between the associated upper trough and a weak ridge across the Caribbean. Scattered to broken multilayered cloudiness and embedded showers lies within 200 nm of the frontal boundary from Southeastern Mexico to the Western Atlantic, while covering the entire Florida Peninsula. Meanwhile, the associated surface high-pressure anticyclone is established 1030 mb over Eastern Texas at 31N/93W. This high is producing exceptionally fair and tranquil conditions over Northern Mexico, much of Texas, the Deep South, Southeast United States and the northwest corner of the Gulf behind the swath of moisture. The high is also producing a strong offshore flow with northerly winds of 25-35 knots and swells of 14 ft mainly west of 90W. As the front moves across the area these conditions should push into the Bay of Campeche and then the Gulf of Tehuantepec in the next 24 hrs. Expect storm force conditions and further upwelling within the Eastern Pacific Ocean. Expect 3-6 ft seas elsewhere across the Gulf waters but increasing to 6-10 ft as the front moves by.

The cold front continues from Central Florida northeastward to a 985 mb low over the Northeast United States near 41N/66W. This section of the front lies within a very favorable upper level environment with ample upper divergence and as a result scattered moderate to strong showers and thunderstorms lies along the front. Further east, a weak surface high is responsible for the weak surface pressure pattern across the Atlantic ahead of the front with 5-10 knot return flow and mainly fair weather.

CENTRAL AMERICA AND THE CARIBBEAN REGION....

Due to the weakening of the subtropical ridge north of region, trades have now decrease to easterly at 10-15 knots and swells are now 3-4 ft and only 7 ft along the Colombian Coast. The bulk of the unsettle weather will be situated in the Northwest Caribbean where the cold front will enter the region bringing increase shower, wind and wave action. As for the remainder of the Caribbean, upper ridging and dry air will continue to maintain a stable airmass over much of the region, resulting in fair weather. Additionally, periods of brief passing showers can be expected across the Lesser Antilles and the Eastern Greater Antilles where the trades are advecting widespread patches of shallow moisture.


by W456
Member Since: July 24, 2005 Posts: 407 Comments: 19076
95. HIEXPRESS
12:18 AM EST on February 27, 2008
The training rains are straining our drains.
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94. KoritheMan
5:11 AM GMT on February 27, 2008
yawn tell me some in i dont no

Wasn't that a bit rude, Taz? >_>
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.