U.S. heavy precipitation events are increasing, but drought is not

By: Dr. Jeff Masters , 3:12 PM GMT on January 25, 2011

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Yesterday, I introduced the National Climatic Data Center's Climate Extremes Index, which uses temperature and precipitation records to see if the U.S. climate is getting more extreme. Today, I'll focus on how the drought and precipitation extremes that go into the Climate Extremes Index have changed over the past century. The three precipitation-related factors to go into the Climate Extremes Index are:

1) The sum of: (a) the monthly percentage of the United States in severe drought (equivalent to the lowest tenth percentile) based on the Palmer Drought Severity Index (PDSI) and (b) the percentage of the United States with severe moisture surplus (equivalent to the highest tenth percentile) based on the PDSI.

2) Twice the value of the percentage of the United States with a much greater than normal proportion of precipitation derived from extreme (equivalent to the highest tenth percentile) 1-day precipitation events.

3) The sum of (a) percentage of the United States with a much greater than normal number of days with precipitation and (b) percentage of the United States with a much greater than normal number of days without precipitation.

Items 1 and 3 have shown no change in annual average value over the past century, but there has been a marked increase in the number of heavy 1-day precipitation events in recent decades. Thus, the record and near-record values of the Climate Extremes Index in recent years have been due to a combination of the increase in heavy 1-day precipitation events and an increase in maximum and minimum temperatures.


Figure 1. The Annual Climate Extremes Index (CEI) for heavy 1-day precipitation events shows that these events, on average, have affected 10% of the U.S. over the past century (black line). However, heavy precipitation events have increased in recent decades. The seven most extreme years since 1910 have all occurred since 1995, with 2010 ranking as the 5th most extreme year in the past 100 years. Image credit: National Climatic Data Center.

Heavy precipitation events
Global warming theory predicts that global precipitation will increase, and that heavy precipitation events--the ones most likely to cause flash flooding--will also increase. This occurs because as the climate warms, evaporation of moisture from the oceans increases, resulting in more water vapor in the air. According to the 2007 Intergovernmental Panel on Climate Change (IPCC) report, water vapor in the global atmosphere has increased by about 5% over the 20th century, and 4% since 1970. The Climate Extremes Index plot for extreme 1-day precipitation events (Figure 1) does indeed show a sharp increase in heavy precipitation events in recent decades, with seven of the top ten years for these events occurring since 1995, and 2010 coming in 5th place in the past 100 years. The increases in heavy precipitation events have primarily come in the spring and summer, when the most damaging floods typically occur. This mirrors the results of Groisman et al. (2004), who found an increase in annual average U.S. precipitation of 7% over the past century, which has led to a 14% increase in heavy (top 5%) and 20% increase in very heavy (top 1%) precipitation events. Kunkel et al. (2003) also found an increase in heavy precipitation events over the U.S. in recent decades, but noted that heavy precipitation events were nearly as frequent at the end of the 19th century and beginning of the 20th century, though the data is not as reliable back then.

Drought and extreme wetness
Global warming theory predicts that although global precipitation should increase in a warmer climate, droughts will also increase in intensity, areal coverage, and frequency (Dai et al., 2004). This occurs because when the normal variability of weather patterns brings a period of dry weather to a region, the increased temperatures due to global warming will intensify drought conditions by causing more evaporation and drying up of vegetation. Increases in drought and flooding are my top two concerns regarding climate change for both the U.S. and the world in the coming century. Two of the three costliest U.S. weather disasters since 1980 have been droughts--the droughts of 1988 and 1980, which cost $71 billion and $55 billion, respectively. The heat waves associated with these droughts claimed over 17,000 lives, according to the National Climatic Data Center publication, Billion-Dollar Weather Disasters. Furthermore, the drought of the 1930s Dust Bowl, which left over 500,000 people homeless and devastated large areas of the Midwest, is regarded to be the third costliest U.S. weather disaster on record, behind Katrina and the 1988 drought. (Ricky Rood has an excellent book on the Dust Bowl that he recommends in a 2008 blog post).


Figure 2. The Annual Climate Extremes Index (CEI) for drought. The worst U.S. droughts on record occurred in the 1930s and 1950s. There has been no trend in the amount of the U.S. covered by drought conditions (blue bars) or by abnormally moist conditions (red bars) over the past century. About 10% of the U.S. is typically covered by abnormally dry or wet conditions (black lines). Image credit: National Climatic Data Center.

The good news is that the intensity and areal coverage of U.S. droughts has not increased in recent decades (blue bars in Figure 2). The portion of the U.S. experiencing abnormal drought and exceptionally wet conditions has remained nearly constant at 10% over the past century. A recent paper by Andreadis et al., 2006, summed up 20th century drought in the U.S. like this: "Droughts have, for the most part, become shorter, less frequent, and cover a smaller portion of the country over the last century. The main exception is the Southwest and parts of the interior of the West, where, notwithstanding increased precipitation (and in some cases increased soil moisture and runoff), increased temperature has led to trends in drought characteristics that are mostly opposite to those for the rest of the country especially in the case of drought duration and severity, which have increased."

Other portions of the globe have not not been so fortunate. Globally, Dai and Trenberth (2004) showed that areas experiencing the three highest categories of drought--severe, extreme, and exceptional--more than doubled (from ~12 to 30%) since the 1970s, with a large jump in the early 1980s due to an El Niño-related precipitation decrease over land, and subsequent increases primarily due to warming temperatures. According to the Global Drought Monitor, 98 million people world-wide currently live in areas experiencing the highest level of drought (exceptional).

References
Andreadis, K. M. Lettenmaier, D. P., "Trends in 20th century drought over the continental United States", Geo. Res. Letters 33, 10, L10403, DOI 10.1029/2006GL025711

Dai A., K.E. Trenberth, and T. Qian, 2004: A global data set of Palmer Drought Severity Index for 18702002: Relationship with soil moisture and effects of surface warming", J. Hydrometeorol., 5, 11171130.

Gleason, K.L., J.H. Lawrimore, D.H. Levinson, T.R. Karl, and D.J. Karoly, 2008: "A Revised U.S. Climate Extremes Index", J. Climate, 21, 2124-2137.

Groisman, P.Y., R.W. Knight, T.R. Karl, D.R. Easterling, B. Sun, and J.H. Lawrimore, 2004, "Contemporary Changes of the Hydrological Cycle over the Contiguous United States: Trends Derived from In Situ Observations," J. Hydrometeor., 5, 64-85.

Kunkel, K. E., D. R. Easterling, K. Redmond, and K. Hubbard, 2003, "Temporal variations of extreme precipitation events in the United States: 1895-2000", Geophys. Res. Lett., 30(17), 1900, doi:10.1029/2003GL018052.

A new Nor'easter for New England
A low pressure system currently centered along the Gulf Coast near New Orleans is bringing heavy rain to much of the south. Rains in excess of 3 inches have fallen over central Mississippi, and the rain is expected to change to snow over northern Mississippi, northern Alabama, and much of Tennessee late tonight. A swath of 2 - 4" of snow is expected in these regions, with higher amounts in the mountains. The low will move off the coast of North Carolina on Wednesday morning, then northeastward out to sea, potentially bringing heavy snows of 4 - 8" to inland portions of New England and the mid-Atlantic. At this time, it appears that the storm will track far enough from the coast and there will be insufficient cold air in place for snowfall amounts of a foot or more to fall. A nasty mix of rain, sleet, and snow is likely for much of the coast, with the heaviest snows expected to miss New York City, Washington D.C., and Boston (Figure 3.) As the low drags its cold front over Florida this afternoon, a slight risk of severe thunderstorms exists, and Florida could see a few tornadoes.


Figure 3. Probability of more than 8 inches of snow falling, for the 24 hour period ending 7am EST Thursday January 27, 2011. Image credit: National Weather Service HPC.


Jeff Masters

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Quoting Jedkins01:


I don't know, that seems like a rather deceptive map, the local NWS has released products saying tornado density per square mile is higher than any other state. Graphs can be kinda deceiving.
That has to include some function of population density in it...right?

Link?
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Quoting hydrus:
Thank you Atmo..I remember you saying that snow is the devils dandruff, death dust...Something in that respect..:)
That would be Presslord.

I don't mind snow, but I never learned a whole lot about winter weather and used it even less.
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Quoting hcubed:
About the main blog - question on chart 1 (The Annual Climate Extremes Index for heavy 1-day precipitation events).

I don't know if the data can be split, but what would that chart look like if the effects of landfalling hurricanes were removed?

Do those years where we see large amounts of hurricanes increase the one day values?

Last year, we had no DIRECT landfalls, but picked up quite a bit of rain from the Mexican landfalls.

Just wonderin' how that would change the chart...
Good point!

Follow that up with: And at hurricane landfalls when did it become important to those on the ground to take a look at the rain gauge? Weeks later, maybe never. So, obs from before WSR-88D during a landfalling hurricane are likely off the mark...and missing substantial rainfall.
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SPC continues to downplay the potentially dangerous situation for Northern/Central Florida.
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Quoting atmoaggie:
I am very much not the snow guy...

But, I do look at the snow depth GFS plots on twisterdata.com for clues.
http://www.twisterdata.com/index.php?prog=forecast&model=GFS&grid=3&model_yyyy=2011& ;model_mm=01&mod el_dd=25&model_init_hh=12&fhour=00¶meter=SNOWIN&level=SURFACE&unit=none& maximize=n&mode=singlema p&sounding=n&output=image&view=large&archive=false

Such as this:
Thank you Atmo..I remember you saying that snow is the devils dandruff, death dust...Something in that respect..:)
Member Since: September 27, 2007 Posts: 1 Comments: 22312
Quoting cchsweatherman:


It seems like Tornado Alley has expanded eastward in time.
I don't think we can confidently say that...

There are plenty of examples of years with as much activity from Ohio to Georgia as in tornado alley, proper, in the records. Though, there does seem to be some indication of that...

1957:


1961:


2006:

(Yeah, maybe? I dunno.)

Very busy 2008:


All maps here: http://www.spc.noaa.gov/wcm/annualtornadomaps/
But, if the eastern areas had a EF-0 briefly touchdown in the 60s, was it classified as a tornado? And today? A higher percentage of the tornadoes that touchdown in the east are EF-0 and EF-1 and brief, relative to the same in tornado alley. This, all by itself, could give that appearance.

Tornadoes records are terrible for detecting trends over the last 50 years...
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Quoting atmoaggie:
Every tornado track from 1950 to 2009 that we know of color coded by EF scale (blue to red; EF-0 to EF-5):


(click for full size)


All nado tracks:


Florida's nado activity doesn't come close to most others from Georgia to the Dakotas no matter how you analyze it.

I'd say, by density, Mississippi might be the "winner".


I don't know, that seems like a rather deceptive map, the local NWS has released products saying tornado density per square mile is higher than any other state. Graphs can be kinda deceiving.
Member Since: August 21, 2008 Posts: 0 Comments: 7992
About the main blog - question on chart 1 (The Annual Climate Extremes Index for heavy 1-day precipitation events).

I don't know if the data can be split, but what would that chart look like if the effects of landfalling hurricanes were removed?

Do those years where we see large amounts of hurricanes increase the one day values?

Last year, we had no DIRECT landfalls, but picked up quite a bit of rain from the Mexican landfalls.

Just wonderin' how that would change the chart...
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So the weather event here in Pensacola was weak at best, what gives? we didnt even get a half inch of rain?
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Quoting Jedkins01:



I agree, they always downplay severe weather forecasts in Florida. Maybe that's why tornado outbreaks have been so deadly here in the past. The last 2 tornado outbreaks in Florida that killed a lot of people both only had been warranted at "slight risk".

Not only that, here in Florida, severe thunderstorms are a common sight especially to inland residents, so if the SPC only puts out a "slight risk". Residents don't exactly come off their seats.

Florida actually gets more tornadoes in number than anywhere in tornado alley, and although most are not intense tornadoes, a tornado is still a tornado, they destroy, and kill, if people get in the wrong place at the wrong time.



Honestly though, the main reason they probably down play the severe threat around here, is during the time we get low pressure systems by which you can make severe forecasts. Its for this time of year meaning the water temps are very cool, which means although storms can look severe, its a tricky call how many of them will actually be completely surfaced based and actually produce severe weather because that cold water acts like a warm front.


That giant pool of water to the west of the FL peninsula still serves as a blind spot for forecasters, in my opinion. Without all of the ground stations that are available elsewhere to measure distinct and fluid changes in the atmospheric profile, there is no way to get as firm a grip on developing weather situations as in the Upper Midwest, for one example.

It is different with tropical weather of course. That is why they have hurricane hunter planes. This allows them to go where no ground instrumentation or ground stations can exist and still get up-to-the-minute observations. As a result, I think the SPC just takes the middle ground and plays it conservative when an atmospheric setup just like the one we are seeing today develops. Issue warnings, make a conservative assessment of risk but just in case some unforeseen circumstance develops which lowers the potential for extreme weather, don't go overboard with the outlook, at least not until very late in the game.

You mentioned the issue of colder near-shore waters in one post last night, Jedkins. Indeed, that is something that puts another "unknown" into the forecasting mix. However, in Florida when a storm such as this one is approaching, there is a strong potential for discreet supercell development over the land areas, especially when an adequate heating up of the lower levels is occurring, such as what appears to be happening today. And that one detail may be where the risk for strong and rapid rotational development is greatest on the FL peninsula today and tonight. Is my guesstimate of this setup at all accurate, in your opinion?
Member Since: October 15, 2010 Posts: 0 Comments: 767
74. Inyo
RE: floods increasing but not droughts... note that water shortages ARE increasing though. For instance, California is constantly hyping its 'droughts' even though there has been no significant decrease in precipitation (if anything, there has been a slight increase).

Some of California's water trouble may be due to more precip in the mountains falling as rain instead of snow. But, most of it is simply due to the fact that water there is horribly mismanaged and misused, from the second it hits the ground until it evaporates or ends up in the ocean
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...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON AND TONIGHT OVER

MUCH OF FL...



...FL...

SRN BRANCH S/W TROUGH WILL PROGRESS EWD ACROSS LWR MS VLY/NRN GULF

OF MEXICO THIS AFTERNOON TO SERN STATES BY 12Z WED AS IT CONTINUES

TO DEEPEN. SURFACE LOW ALONG THE SERN LA/SRN MS COAST WILL DEVELOP

ENEWD ALONG STRENGTHENING BAROCLINIC ZONE DEVELOPING NWD THROUGH NRN

FL/SRN GA BY LATE THIS AFTERNOON INTO TONIGHT.



GULF MOISTURE IS SPREADING NWD THRU FL PENINSULA ON STRENGTHENING

LOW LEVEL SLY FLOW WITH 850 WINDS TO 35-40KT BY MID AFTERNOON

CENTRAL FL PENINSULA NWD.



WITH INCREASING THUNDERSTORMS NOTED OVER NERN GULF AND LATEST

MESOSCALE MODEL GUIDANCE IT STILL APPEARS THERE IS THE POTENTIAL FOR

TWO DISTINCT TSTM REGIMES DURING THE DAY ONE PERIOD. THE DOMINANT

AND MOST PROBABLE REGIME WILL BE THE DEVELOPMENT OF A SQUALL LINE

AHEAD OF THE SYNOPTIC COLD FRONT WHICH WILL PROGRESS FROM THE NERN

GULF OF MEXICO EWD THROUGH AT LEAST THE NRN HALF OF THE PENINSULA

BETWEEN 00-06Z. BASED ON THE HIGHER RESOLUTION MODEL DATA

SETS...CONVECTIVE MODE WILL LIKELY BE LINEAR QLCS WITH THE POTENTIAL

FOR EMBEDDED BOWING STRUCTURES CAPABLE OF DAMAGING WIND GUSTS AND

PERHAPS A BRIEF TORNADO OR TWO.



THERE REMAINS UNCERTAINTY OF THE POTENTIALLY MORE SIGNIFICANT SECOND

REGIME WHICH COULD DEVELOP BY LATER THIS AFTERNOON OVER THE FL

PENINSULA WHERE HEATING WILL BE SUFFICIENT TO SUPPORT SURFACE BASED

THUNDERSTORMS. FORECAST SOUNDING DATA INDICATE LITTLE CAP WILL

REMAIN ONCE TEMPS WARM INTO THE MID 70S AND DEWPOINTS RISE INTO THE

MID 60S. AT THAT POINT MLCAPE OF 500-1000 J PER KG/ AIR MASS

COINCIDENT WITH 40-45 KT OF DEEP WLY SHEAR AND 0-1 KM SRH OF 150-250

M2/S2 WOULD BE SUPPORTIVE OF MORE DISCRETE STORM MODES INCLUDING

SUPERCELLS CAPABLE OF DAMAGING WINDS AND A FEW TORNADOES BY LATER

THIS AFTERNOON.



..COASTAL CAROLINAS...



MODEL GUIDANCE REMAINS CONSISTENT IN INDICATING THAT THE

TRACK OF THE DEVELOPING SURFACE LOW WILL REMAIN ALONG INTENSIFYING

COASTAL BOUNDARY WITH ANY MEANINGFUL INSTABILITY LIKELY REMAINING

OFFSHORE. HOWEVER WILL MAINTAIN LOW PROPS OF SEVERE VICINITY OUTER

BANKS AS SOME ELEVATED INSTABILITY INDICATED IN THE MODEL FORECAST

SOUNDINGS NEAR THE END OF THE PERIOD.



..HALES/HURLBUT.. 01/25/2011
Member Since: July 15, 2006 Posts: 176 Comments: 55665
I agree, atmo, I agree. Just didn't want FlaHeat to think that all we got was over-glorified dust devils.
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Quoting eddye:
will south fla get any severe weather cchs our anyone who is here in broward because i live there and i want 2 know


Our main threat in South Florida is winds as the storms will become more linear late tonight. You can't rule out a supercell or two, but more likely it would be wind gusts. There is an outside chance of late afternoon storms west of Lake Okeechobee with those having greater potential for tornadoes.

Adrian
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Nice post, Dr. Masters.

"Globally, Dai and Trenberth (2004) showed that areas experiencing the three highest categories of drought--severe, extreme, and exceptional--more than doubled (from ~12 to 30%) since the 1970s, with a large jump in the early 1980s due to an El Niño-related precipitation decrease over land, and subsequent increases primarily due to warming temperatures. According to the Global Drought Monitor, 98 million people world-wide currently live in areas experiencing the highest level of drought (exceptional)."

This is very worrisome.
Member Since: November 8, 2009 Posts: 4 Comments: 13743
Member Since: July 15, 2006 Posts: 176 Comments: 55665
Quoting hydrus:
Good morning Atmo. Could you please post a link that has a decent snowfall prediction model?..
I am very much not the snow guy...

But, I do look at the snow depth GFS plots on twisterdata.com for clues.
http://www.twisterdata.com/index.php?prog=forecast&model=GFS&grid=3&model_yyyy=2011&model_mm=01&mod el_dd=25&model_init_hh=12&fhour=00¶meter=SNOWIN&level=SURFACE&unit=none&maximize=n&mode=singlema p&sounding=n&output=image&view=large&archive=false

Such as this:
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Quoting atmoaggie:
Every tornado track from 1950 to 2009 that we know of color coded by EF scale (blue to red; EF-0 to EF-5):


(click for full size)


All nado tracks:


Florida's nado activity doesn't come close to most others from Georgia to the Dakotas no matter how you analyze it.

I'd say, by density, Mississippi might be the "winner".


It seems like Tornado Alley has expanded eastward in time.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
Quoting eddye:
deal cchsweather man sorry i asked u 2 much about weather


Now you can add me back on Facebook.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
deal cchsweather man sorry i asked u 2 much about weather
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Quoting atmoaggie:
Dat's what I read...
Good morning Atmo. Could you please post a link that has a decent snowfall prediction model?..
Member Since: September 27, 2007 Posts: 1 Comments: 22312
Quoting aquak9:
naaaahhh...we don't have disasterous tornadoes here in Fla. We just pluck the bodies outta trees.

www.foxnews.com/story/0,2933,249758,00.html

(can't link from work)
Not saying it doesn't happen...

Just that if one were to get into a [snip]ing contest about it, Florida loses badly.
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Quoting atmoaggie:
Every tornado track from 1950 to 2009 that we know of color coded by EF scale (blue to red; EF-0 to EF-5):


(click for full size)


Florida's nado activity doesn't come close to most others from Georgia to the Dakotas no matter how you analyze it.


Now that is one neat map, thanks
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naaaahhh...we don't have disasterous tornadoes here in Fla. We just pluck the bodies outta trees.

www.foxnews.com/story/0,2933,249758,00.html

(can't link from work)
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Quoting eddye:
cchs i need your website and i need 2 know if u still have a facebook


During winter break, I took down my website. Currently am in the process of coming up with a design for a new website I will be putting up in the coming weeks.

As far as Facebook, yes I do. As long as you don't stalk me asking me about weather all the time, I'll remove the block.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
Quoting FloridaHeat:


So we get a rain and then a squally line tongiht that has the severe weather in it?


Thats about right. You'll have a few individual storms before the squall line that should be coming into your area this evening around 7.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
cchs i need your website and i need 2 know if u still have a facebook
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Quoting cchsweatherman:


Seems like rains and storms should be building into your area around the mid-afternoon hours between 1:30 and 3 PM.


So we get a rain and then a squally line tongiht that has the severe weather in it?
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Every tornado track from 1950 to 2009 that we know of color coded by EF scale (blue to red; EF-0 to EF-5):


(click for full size)


All nado tracks:


Florida's nado activity doesn't come close to most others from Georgia to the Dakotas no matter how you analyze it.

I'd say, by density, Mississippi might be the "winner".
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Quoting FloridaHeat:


I read that tornadoes are not the same in Florida either that they are normal very weak and cause very little damage and do not have long tracking. Very different from Oklahoma.


please google "Lady lake florida tornadoes"

grrrrrr
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Quoting eddye:
so south florida wont be geting hail


Its possible that South Florida could see some hail, especially in the squall line that will be coming overnight.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
Quoting Jedkins01:


lol I hoped so, but people are known for being, should I say, not being very knowledgeable down here lol, so I wasn't sure if you were joking or not.


That is like saying go get in a car or a mobile home to ride out a tornado. LOL
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Quoting FloridaHeat:


So I should be concerned in my area then? I have a pick up soccer game with friends and I hope that does not get rain out.


Seems like rains and storms should be building into your area around the mid-afternoon hours between 1:30 and 3 PM.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
so south florida wont be geting hail
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Quoting FloridaHeat:


The pool part was sort of a joke.


lol I hoped so, but people are known for being, should I say, not being very knowledgeable down here lol, so I wasn't sure if you were joking or not.
Member Since: August 21, 2008 Posts: 0 Comments: 7992
Quoting cchsweatherman:


Typically seen as the area between Ocala and Lake Okeechobee.


So I should be concerned in my area then? I have a pick up soccer game with friends and I hope that does not get rain out.
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Quoting FloridaHeat:


What do you define as central florida?


You are technically Central Florida. I'm referring to the I-4 corridor when I'M saying greatest threat, however, you are close enough and your threat will likely only be a little less.


Keep in mind, it all depends on where the strongest cells line up to know exactly where, which we really won't know to the squall line approaches later. But like I said, your threat will be higher than south Florida.
Member Since: August 21, 2008 Posts: 0 Comments: 7992
Quoting Jedkins01:



You should always go to in interior room or enclosure in your home, the pool would not be smart idea, it will just suck the water right out. Laying down in a bath tub with your head protected, or in a closet, or under a bed are good choices.


The pool part was sort of a joke.
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Quoting FloridaHeat:


What do you define as central florida?


Typically seen as the area between Ocala and Lake Okeechobee.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
Quoting FloridaHeat:


I will stay tune then. What time would the biggest threat be for Lakewood Ranch (Sarasota area).


Anywhere south of Tampa/Orlando will be late night.
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Quoting eddye:
why is it always north florida lol


Because low pressure systems typically bring the highest threat of strong dynamics and shear to the northern half of the state. Its just how most low pressure tracks occur.
Member Since: August 21, 2008 Posts: 0 Comments: 7992
Quoting eddye:
i thought south florida geting worse weather then orlando


That has never been the case. Don't know where you got that information from. Yes there will be strong to severe thunderstorms in South Florida possible, but the greatest threat lies with those in Central Florida as the best dynamics for rotating storms will occur there.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
Quoting Jedkins01:


nope, highest threat is in Central Florida.


What do you define as central florida?
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Quoting FloridaHeat:
What happens if a tornado comes here because nobody has a basement or storm celler. At least in Oklahoma I could go to the storm celler or a basement if a tornado was close. I guess I would go out and get in the pool for safety?



You should always go to in interior room or enclosure in your home, the pool would not be smart idea, it will just suck the water right out. Laying down in a bath tub with your head protected, or in a closet, or under a bed are good choices.
Member Since: August 21, 2008 Posts: 0 Comments: 7992
Quoting eddye:
i thought south florida geting worse weather then orlando


nope, highest threat is in Central Florida.
Member Since: August 21, 2008 Posts: 0 Comments: 7992
What happens if a tornado comes here because nobody has a basement or storm celler. At least in Oklahoma I could go to the storm celler or a basement if a tornado was close. I guess I would go out and get in the pool for safety?
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Quoting atmoaggie:
But that's more a function of population density than anything else. Florida generally lacks the shear needed to spin up a EF-4, as there is no Mexico to the SSW.


Oh of course that's true. My point was, not every tornado is an F-0 here. And Tornado density is better term to use then number by state, because not all states are the same size, and that gives Texas an unfair sway in statistics. Density, is a more fair and accurate tool to use.
Member Since: August 21, 2008 Posts: 0 Comments: 7992
i thought south florida geting worse weather then orlando
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Quoting beell:
Never heard of isotropic lift, flood.
Isentropic maybe?
Dat's what I read...
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why is it always north florida lol
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Quoting reedzone:


I agree, in reality.. It looks to be a busy evening for me, it's warm, windy, and partly cloudy which means the instability is good.


I will stay tune then. What time would the biggest threat be for Lakewood Ranch (Sarasota area).
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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.

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