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 NiƱo-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:
Looks like the line is beginning to weaken as a result of upper energy and low level jet lifting out to the northeast.

However, not to downplay the squall line, its still a line of strong storms, however it has lost punch obviously compared to earlier, when at one point up to 7 active tornado warnings at one time were present and even more severe thunderstorms warnings on top of that. Now all warnings have ended.


I'd have to disagree especially with multiple TV signatures developing in the past hour.
Member Since: April 14, 2007 Posts: 8 Comments: 5030
Looks like the line is beginning to weaken as a result of upper energy and low level jet lifting out to the northeast.

However, not to downplay the squall line, its still a line of strong storms, however it has lost punch obviously compared to earlier, when at one point up to 7 active tornado warnings at one time were present and even more severe thunderstorms warnings on top of that. Now all warnings have ended.
Member Since: August 21, 2008 Posts: 0 Comments: 6867
Quoting FLWaterFront:


Yep. Last year, the Gulf off of Clearwater Beach reached a low water temperature reading of 48F in mid-January, after 2 weeks of exceptionally (a record in terms of duration) cold weather.

But this year it has been as low as 50F and it has hung in the low or mid fifties most of the way since early December. Those are the temps for the near shore waters, of course, but still, they are a lot colder than is normal, especially for such a long period of time.

This storm system of today got very strong in spite of such colder than normal near shore water temperatures. One can only wonder what it would have been like had the water temperatures been well above average.
Member Since: July 15, 2006 Posts: 163 Comments: 52257
Quoting FLWaterFront:


Yep. Last year, the Gulf off of Clearwater Beach reached a low water temperature reading of 48F in mid-January, after 2 weeks of exceptionally (a record in terms of duration) cold weather.

But this year it has been as low as 50F and it has hung in the low or mid fifties most of the way since early December. Those are the temps for the near shore waters, of course, but still, they are a lot colder than is normal, especially for such a long period of time.

This storm system of today got very strong in spite of such colder than normal near shore water temperatures. One can only wonder what it would have been like had the water temperatures been well above average.


Yeah really! Imagine if we got this setup in March or April!
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Quoting cchsweatherman:
TWO TORNADO VORTEX SIGNATURES DETECTED IN EVERGLADES AND MOVING INTO BROWARD COUNTY.


It's gonna be an interesting night here in downtown Miami.



THE NATIONAL WEATHER SERVICE IN MIAMI HAS ISSUED A

* SIGNIFICANT WEATHER ADVISORY FOR...
WESTERN BROWARD COUNTY
NORTHWESTERN MIAMI-DADE COUNTY
SOUTHWESTERN PALM BEACH COUNTY
SOUTHEASTERN HENDRY COUNTY
EAST CENTRAL COLLIER COUNTY

* FOR FREQUENT TO EXCESSIVE LIGHTNING...GUSTY WINDS FROM 45 TO 55
MPH...FUNNEL CLOUDS

* UNTIL 1015 PM EST.
AT 936 PM EST...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 6 MILES NORTH OF BIG
CYPRESS SEMINOLE INDIAN RESERVATION TO 5 MILES NORTH OF BIG CYPRESS
NATIONAL PRESERVE...MOVING SOUTHEAST AT 55 MPH.
BIG CYPRESS SEMINOLE INDIAN RESERVATION COLLIER/BROWARD LINE AND
ALLIGATOR ALLEY MICCOSUKEE SERVICE PLAZA INTERSECTION ALLIGATOR
ALLEY AND MIAMI CANAL AND SURROUNDING COMMUNITIES.
THE PRIMARY IMPACTS WILL BE FREQUENT TO EXCESSIVE LIGHTNING AND GUSTY
WINDS OF 45 TO 55 MPH. LIGHTNING IS THE NUMBER ONE WEATHER RELATED
KILLER IN FLORIDA. TREES AND OPEN SHELTERS OFFER NO PROTECTION. THESE
WINDS CAN DOWN SMALL TREE LIMBS AND BRANCHES...AND BLOW AROUND
UNSECURED SMALL OBJECTS. SEEK SHELTER IN A SAFE BUILDING UNTIL THE
STORM PASSES.
A TORNADO WATCH REMAINS IN EFFECT UNTIL MIDNIGHT EST WEDNESDAY
MORNING FOR SOUTHERN FLORIDA.
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Quoting Jedkins01:


lol you might wanna take that back, water temps are not warm unlike last year, this system just had a lot of dynamics, moisture, and energy to work with. The water temps are in the low to mid 50's off the coast here. Virtually the same as last winter actually.

Unless you are referring to the warm loop current? If that's the case, any energy those storms get from that loop current, won't make a difference for Florida, because they must travel over cold water soon after.


Yep. Last year, the Gulf off of Clearwater Beach reached a low water temperature reading of 48F in mid-January, after 2 weeks of exceptionally (a record in terms of duration) cold weather.

But this year it has been as low as 50F and it has hung in the low or mid fifties most of the way since early December. Those are the temps for the near shore waters, of course, but still, they are a lot colder than is normal, especially for such a long period of time.

This storm system of today got very strong in spite of such colder than normal near shore water temperatures. One can only wonder what it would have been like had the water temperatures been well above average.
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centre fix relocated
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Quoting Jedkins01:


lol you might wanna take that back, water temps are not warm unlike last year, this system just had a lot of dynamics, moisture, and energy to work with. The water temps are in the low to mid 50's off the coast here. Virtually the same as last winter actually.

Unless you are referring to the warm loop current? If that's the case, any energy those storms get from that loop current, won't make a difference for Florida, because they must travel over cold water soon after.


Well, won't be long until those SST's in the GOMEX will make a major comeback.
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Member Since: July 15, 2006 Posts: 163 Comments: 52257
Member Since: July 15, 2006 Posts: 163 Comments: 52257
TWO TORNADO VORTEX SIGNATURES DETECTED IN EVERGLADES AND MOVING INTO BROWARD COUNTY.


Member Since: April 14, 2007 Posts: 8 Comments: 5030
573. HadesGodWyvern (Mod)
Fiji Meteorological Services
Tropical Cyclone Advisory #18
SEVERE TROPICAL CYCLONE WILMA (06F)
12:00 PM FST January 26 2011
===================================

At 0:00 AM UTC, Severe Tropical Cyclone Wilma, Category Four (950 hPa) located at 22.9S 177.2E has 10 minute winds of 90 knots and is reported as moving west southwest at 18 knots. Position GOOD based on multispectral visible/infrared imagery and peripheral surface observations.

Hurricane Force Winds
======================
20 NM from the center

Storm Force Winds
=================
30 NM from the center

Gale Force Winds
================
120 NM from the center in northeast quadrant, 200 NM in the southeastern quadrant, and 90 NM from the center elsewhere

Additional Information
=========================

Overall organization remains good past 24 hours. Eye well defined. WILMA continues to intensify with eye warming and convective tops cooling. Outflow good to the east and south but restricted elsewhere. WILMA steered by southeast deep layer mean. System lies under an upper diffluent region. CIMSS indicates decreasing shear along forecast path. Sea surface temperature is around 28C.

Dvorak analysis based on OW eye and B surrounding, yielding DT=5.5 MET=5.5 PT=5.5. Final Dvorak T number based on DT.

Dvorak Intensity: T5.5/5.5/D1.0/24HRS.

Most global models move WILMA west southwest with some intensification.

Forecast and Intensity
============================
12 HRS: 23.8S 174.5E - 90 knots (CAT 4)
24 HRS: 24.8S 172.3E - 90 knots (CAT 4)
48 HRS: 27.8S 169.1E - 85 knots (CAT 3)

The next Tropical Disturbance Advisory from Fiji Meteorological Services will be issued at around 8:30 AM UTC..
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Quoting DontAnnoyMe:


Just choose 'Modify comment' and wipe it out. But you have to put in something, like a period.
Okay I had edit it with an apology note insted for giving the wrong information.
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Quoting Grothar:
Looks like the squall line is getting stronger.

Yes it does...I have seen quite a few like that in the past.
Member Since: September 27, 2007 Posts: 1 Comments: 19521
Quoting washingtonian115:
The sst map I was reading might of been wrong then.Sadly I really don't know how to delete coments.


Just choose 'Modify comment' and wipe it out. But you have to put in something, like a period.
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"The Future is Our's to Win"
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Quoting washingtonian115:
The sst map I was reading might of been wrong then.Sadly I really don't know how to delete coments.



I don't either lol, its all good though.
Member Since: August 21, 2008 Posts: 0 Comments: 6867
Quoting Jedkins01:


lol you might wanna take that back, water temps are not warm unlike last year, this system just had a lot of dynamics, moisture, and energy to work with. The water temps are in the low to mid 50's off the coast here. Virtually the same as last winter actually.
The sst map I was reading might of been wrong then.Sadly I really don't know how to delete coments.
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Quoting washingtonian115:
Okay folks,ya gotta remember that unlike last year sst in the southern GOM are still warm,and that's one thing that's help fuling those thunderstorms.And to all you floridians stay safe and listn to local officials about warnings,and the latest with the weather.Have your weather emergency kit on hand as well.


lol you might wanna take that back, water temps are not warm unlike last year, this system just had a lot of dynamics, moisture, and energy to work with. The water temps are in the low to mid 50's off the coast here. Virtually the same as last winter actually.

Unless you are referring to the warm loop current? If that's the case, any energy those storms get from that loop current, won't make a difference for Florida, because they must travel over cold water soon after.
Member Since: August 21, 2008 Posts: 0 Comments: 6867
Quoting DontAnnoyMe:


Pick up your keyboard, turn it over, and give it a few hard shakes in all directions.
I'll try it!.
Quoting TropicalAnalystwx13:


Several reports of Severe flooding (In some cases, water up to the doors of houses) across Florida. Power outages being reported in the same area.
I Hope those people were prepared,and got out safely.
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Quoting Neapolitan:
The squall line passed through my part of Naples a few minutes ago. A couple of lightning flashes, very little wind, and heavy rain (500-55 dBZ) for three minutes or so. We're on the back side of the line now; the rain is steady, but lighter (35 dBZ). That's okay; the slower it comes, the less it will run off into the Gulf. In fact, a couple of hours at this rate would be just fine by me... ;-)


Sure sounds like a heck of a lot less than we got up here in Pinellas County!
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Quoting MiamiHurricanes09:


Just had to post a bigger image than mine, huh?? LOL
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Here we were writing off the poor system, and now look...Seems to be a Category 3/4 (I do not really keep up with systems that aren't in the ATL, so I do not know the strength of the system).



For that reason, I'm not writing Anthony off...But the poor system looks like it is having quite a hard time with Wind Shear (Looks kind of like Fiona being sheared from Earl).

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561. JRRP
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Quoting washingtonian115:
Got dammit,that E key of mine is acting up.Looks like rough night in florida.Has their been any reports of flooding/power outage down there?


Several reports of Severe flooding (In some cases, water up to the doors of houses) across Florida. Power outages being reported in the same area.
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Looks like the squall line is getting stronger.

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Quoting washingtonian115:
Got dammit,that E key of mine is acting up.


Pick up your keyboard, turn it over, and give it a few hard shakes in all directions.
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Quoting washingtonian115:
Oh that's wondrful.
Got dammit,that E key of mine is acting up.Looks like rough night in florida.Has their been any reports of flooding/power outage down there?
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Quoting TropicalAnalystwx13:
The system currently producing the Tornadic thunderstorms across Florida should re-strengthen once emerging off the East Coast of the United States, and become a heavy Snow producer for the Northeast.

The storm next week could be a whole lot worse in terms of Snowfall though...
Oh that's wondrful.
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NWS Storm Reports

Note: All data are considered preliminary
Tornado Reports (CSV) (Raw Tornado CSV)(?)
Time Location County State Lat Lon Comments
2315 4 WNW MYAKKA HEAD MANATEE FL 2750 8214 PUBLIC REPORT OF TORNADO TOUCHDOWN NEAR HIGHWAY 64 AND WINGATE ROAD. NO DAMAGE REPORTED AT THIS TIME. (TBW)
Hail Reports (CSV) (Raw Hail CSV)(?)
No reports received
Wind Reports (CSV) (Raw Wind CSV)(?)
Time Speed Location County State Lat Lon Comments
2210 75 2 N SAINT PETERSBURG PINELLAS FL 2779 8267 ESTIMATED WIND GUSTS OF 70 TO 75 MPH. BRANCHES BREAKING OFF TREES. (TBW)
2221 UNK GROVELAND LAKE FL 2856 8185 INTERSECTION OF SR 19/50 TREES DOWN ON 12 TO 20 HOMES. REPORT FROM LAKE COUNTY EM. (MLB)
2224 60 4 SSE TAMPA HILLSBOROUGH FL 2791 8245 60 MPH WIND GUST REPORTED. (TBW)
2235 UNK 2 NNW SAINT PETERSBURG PINELLAS FL 2778 8268 GAS STATION CANOPY COLLAPSED NEAR INTERSECTION OF 38TH AVE N AND 24TH ST N. (TBW)
2307 UNK LAKE MARY SEMINOLE FL 2876 8133 POWER LINES DOWN AT WESLEY LAKE AND MEADOW BAY COURT (MLB)
2314 63 SANFORD SEMINOLE FL 2879 8128 SANFORD/ORLANDO AIRPORT ASOS PEAK WIND 27055/2314 (MLB)
2323 UNK GENEVA SEMINOLE FL 2874 8112 SANFORD PD REPORTED POWER LINES DOWN AT OSCEOLA ROAD AND OSC
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Wind gust reported earlier by my house in St.Petersburg of 75MPH. Gas station cover tipped over and crushed a car, also many trees down in the area.
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The squall line passed through my part of Naples a few minutes ago. A couple of lightning flashes, very little wind, and heavy rain (50-55 dBZ) for three minutes or so. We're on the back side of the line now; the rain is steady, but lighter (35 dBZ). That's okay; the slower it comes, the less it will run off into the Gulf. In fact, a couple of hours at this rate would be just fine by me... ;-)
Member Since: November 8, 2009 Posts: 4 Comments: 13268
550. HadesGodWyvern (Mod)
Tropical Cyclone Warning Center Perth
Tropical Cyclone Advice #16
TROPICAL CYCLONE BIANCA (12U)
9:00 AM WST January 26 2011
=======================================

At 8:00 am WST, Tropical Cyclone Bianca, Category Two (984 hPa) located at 18.8S 119.7E, or 285 km west southwest of Broome and 205 km northeast of Port Hedland has 10 minute sustained winds of 50 knots with gusts of 70 knots. The cyclone is reported as moving southwest at 13 knots.

Storm Force Winds
================
30 NM from the center

Gale Force Winds
=================
60 NM from the center

Dvorak Intensity: T3.5/3.5/D1.5/24HRS

Tropical Cyclone Bianca continues to develop as it moves to the southwest over open waters west of Broome. The cyclone is expected to intensify further as it moves steadily parallel to the Pilbara coast today and on Thursday.

Gales are expected for a period between Wallal and Port Hedland this morning, extending to Karratha tonight and then to Coral Bay on Thursday. Destructive winds with gusts to 160 kilometres per hour are possible between Port Hedland and Karratha later today and moving further west overnight.

Heavy rain is expected in coastal parts between Cape Leveque and Port Hedland, extending west later today and on Thursday. Localised stream rises are likely but widespread flooding is not expected.

Residents of Port Hedland and Karratha are warned of the potential for a dangerous storm tide. Tides may rise significantly above the normal high tide mark with damaging waves and dangerous flooding.

Tropical Cyclone Warnings/Watch
================================
A Cyclone WARNING is current for coastal and island communities from Wallal to Coral Bay.

The Cyclone WARNING for coastal communities between Bidyadanga and Wallal has been cancelled.

Forecast and Intensity
=======================
12 HRS: 19.6S 117.9E - 55 knots (CAT 2)
24 HRS: 20.6S 115.6E - 70 knots (CAT 3)
48 HRS: 23.7S 110.5E - 75 knots (CAT 3)
72 HRS: 28.5S 108.2E - 55 knots (CAT 2)

Additional Information
========================

0.8-1.0 banding on recent IR imagery gives 3.5 DT. MET is 3.0, PAT 3.5. FT is set to 3.5 within constraints and hence CI is 3.5. ADT indicates CI around 3.1 but may be having some issues with intensifying this sytem rapidly enough. Raw DTs are around 3.8. AMSU intensity estimate at 17Z indicated 1-min mean of 51 knots but may have a slight high bias.

Port Hedland radar shows early signs of a tighter inner eye wall [radius around 20-25nm] replacing the large banding eye evident in IR. Shear is low [4.4m/s at 18Z] and expected to increase only marginally over the next 48 hours. Ocean heat content is high along the forecast track over the next 36 hours. Hence further intensification is forecast. By late Wednesday or Thursday it is likely to reach severe cyclone [hurricane] intensity. Weakening is then likely from late Friday as the system moves over cooler SSTs and experiences increasing shear.

The system is expected to be steered steadily towards the west southwest by a strong mid-level ridge until late Friday when an amplifying trough will result in the system being steered towards the south. On Sunday the remnants of the system will experience very high shear as a strong surface ridge pushes in beneath the mid level trough.

The next tropical cyclone advice on Tropical Cyclone Bianca will be at 3:00 AM UTC..
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The system currently producing the Tornadic thunderstorms across Florida should re-strengthen once emerging off the East Coast of the United States, and become a heavy Snow producer for the Northeast.

The storm next week could be a whole lot worse in terms of Snowfall though...
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I would not be surprised to see Warnings later on tonight, looking at the large number of Meso Cyclones that are appearing on the line moving down this way.
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Member Since: July 15, 2006 Posts: 163 Comments: 52257
About damn time they issued the Tornado Watch for South Florida.
Member Since: April 14, 2007 Posts: 8 Comments: 5030
Upadated Miami NWS Discussion:

THE FORECAST REASONING CONTINUES UNCHANGED SINCE EARLIER THIS
AFTERNOON. AN AREA OF MOISTURE CONVERGENCE WEST OF COLLIER COUNTY
COULD LEAD TO THE FORMATION OF SOME DISCRETE ISOLATED
THUNDERSTORMS WITH THE POTENTIAL OF BECOMING SEVERE. ANOTHER AREA
OF MOISTURE CONVERGENCE IS LOCATED OVER THE SOUTHERN TIP OF THE
PENINSULA. THE MAIN ENERGY TO FUEL TORNADIC SUPERCELLS IS FORECAST
TO MOVE NORTHEAST AS THE LINE OF STORMS CONTINUES TO PUSH
SOUTHEASTWARD. ACCORDING TO THE SPC MESOSCALE ANALYSIS THE 0-6 KM
SHEAR IS LESS THAN 50 KNOTS SOUTH OF PALM BEACH AND HENDRY
COUNTIES WITH A TONGUE OF 50 KNOT SHEAR EXTENDING INTO THE GULF OF
MEXICO SOUTHWEST OF COLLIER COUNTY. THE SURFACE TO 1KM SHEAR
INCREASES AS WE MOVE NORTHWARD. AT 730 PM EST THE STRONGEST
LIGHTNING ACTIVITY IS LOCATED OVER THE GULF OF MEXICO NORTHWEST OF
COLLIER COUNTY. IF AN ISOLATED TORNADO WERE TO OCCUR THIS EVENING
IT WILL MOST LIKELY OCCUR JUST AHEAD OF THE MAIN SQUALL LINE. NORTHERN
COLLIER...HENDRY...AND NORTH PALM BEACH COUNTIES INCLUDING LAKE
OKEECHOBEE WILL BE THE FIRST LOCATIONS TO RECEIVE THE IMPACT OF
THE SQUALL LINE WITHIN THE NEXT 45 MINUTES TO AN HOUR AND A HALF.
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Member Since: July 15, 2006 Posts: 163 Comments: 52257
THE NATIONAL WEATHER SERVICE IN MELBOURNE HAS ISSUED A

* TORNADO WARNING FOR...
SOUTHEASTERN INDIAN RIVER COUNTY IN FLORIDA...
THIS INCLUDES THE CITIES OF...SEBASTIAN...WINTER BEACH...WABASSO...
VERO BEACH SOUTH...VERO BEACH...SEBASTIAN INLET...INDIAN RIVER
SHORES...GIFFORD...
OKEECHOBEE COUNTY IN FLORIDA...
THIS INCLUDES THE CITIES OF...OKEECHOBEE...FORT DRUM...BASINGER...
NORTHERN ST. LUCIE COUNTY IN FLORIDA...
THIS INCLUDES THE CITY OF INDRIO...

* UNTIL 915 PM EST.


* AT 806 PM EST...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED
SEVERAL CIRCULATION CAPABLE OF PRODUCING TORNADOES...ALONG A SQUALL
LINE PUSHING INTO INDIAN RIVER...SAINT LUCIE AND MARTIN COUNTIES.
THE CIRCULATIONS WERE LOCATED NEAR VERO LAKE ESTATES...FORT DRUM
AND JUST SOUTH OF BASINGER...AND WERE MOVING EAST AT 35 MPH.


* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO FOUR
SEASONS ESTATES...VERO LAKE ESTATES...SEBASTIAN INLET RECREATION...
LAKEWOOD PARK...VERO BEACH HIGHLANDS...SOUTH BEACH...SAINT LUCIE
AIRPORT...SAINT LUCIE VILLAGE AND QUEENS COVE
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782

NWUS22 KWNS 260106

STAHRY



SPC TORNADO AND SEVERE THUNDERSTORM REPORTS

UNOFFICIAL - FOR OFFICIAL REPORTS, SEE PUBLICATION 'STORM DATA'

FOR 06CST TUE JAN 25 2011 THRU 19CST TUE JAN 25 2011



EVENT LOCATION REMARKS (CST)TIME



.....TORNADO REPORTS..........TORNADO REPORTS..........TORNADO REPORTS.....



1 *TORN 4 WNW MYAKKA HEAD FL (25 ENE SRQ) 25/1715

PUBLIC REPORT OF TORNADO TOUCHDOWN NEAR HIGHWAYTBW/LSR 2750 8214

64 AND WINGATE ROAD. N





.......LRG HAIL/STRONG WIND RPTS.............LRG HAIL/STRONG WIND RPTS......



3 WNDG SPRING HILL FL (35 NNE PIE) 25/1545

DAMAGE REPORTED TO TWO WINDOWS AND GARAGE DOOR.TBW/LSR 2844 8256

EXACT LOCATION NOT KNO

9 G 65 2 N SAINT PETERSBURG FL (8 S PIE) 25/1610

ESTIMATED WIND GUSTS OF 70 TO 75 MPH. BRANCHES TBW/LSR 2779 8267

BREAKING OFF TREES.

4 WNDG GROVELAND FL (31 W ORL) 25/1621

INTERSECTION OF SR 19/50 TREES DOWN ON 12 TO 20MLB/LSR 2856 8185

HOMES. REPORT FROM LAK

10 G 52 4 SSE TAMPA FL (13 E PIE) 25/1624

60 MPH WIND GUST REPORTED. TBW/LSR 2791 8245

5 WNDG 2 NNW SAINT PETERSBURG FL (9 S PIE) 25/1635

OF 38TH AVE N AND 24TH

6 WNDG LAKE MARY FL (13 N ORL) 25/1707

POWER LINES DOWN AT WESLEY LAKE AND MEADOW BAY MLB/LSR 2876 8133

COURT

11 G 55 SANFORD FL (16 N ORL) 25/1714

SANFORD/ORLANDO AIRPORT ASOS PEAK WIND MLB/LSR 2879 8128

27055/2314

7 WNDG GENEVA FL (17 NE ORL) 25/1723

SANFORD PD REPORTED POWER LINES DOWN AT OSCEOLAMLB/LSR 2874 8112

ROAD AND OSCEOLA BLUFF

12 G 52 PORT ORANGE FL (3 SSE DAB) 25/1731

MLB/LSR 2912 8103





.........OTHER SEVERE REPORTS..................OTHER SEVERE REPORTS.........



2 A100 6 W BROOKSVILLE FL (44 NNE PIE) 25/1540

QUARTER SIZE HAIL REPORTED TBW/LSR 2855 8249

8 G 50 2 NNE MASARYKTOWN FL (40 NNE PIE) 25/1544

50 KNOT WIND GUST REPORTED AT BROOKSVILLE TBW/LSR 2847 8245

HERNANDO COUNTY AIRPOR
Member Since: July 15, 2006 Posts: 163 Comments: 52257
THE NATIONAL WEATHER SERVICE HAS ISSUED TORNADO WATCH 8 IN EFFECT UNTIL MIDNIGHT EST TONIGHT FOR THE FOLLOWING AREAS

IN FLORIDA THIS WATCH INCLUDES 5 COUNTIES

IN SOUTH FLORIDA

BROWARD COLLIER GLADES HENDRY PALM BEACH

THIS INCLUDES THE CITIES OF... CLEWISTON... FORT LAUDERDALE... LA BELLE... MOORE HAVEN... NAPLES AND WEST PALM BEACH. TORNADOES... HAIL TO 0.5 INCH IN DIAMETER... THUNDERSTORM WIND GUSTS TO 70 MPH... AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

REMEMBER... A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR TORNADOES 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.

Member Since: Posts: Comments:


SEL8

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 8
NWS STORM PREDICTION CENTER NORMAN OK
800 PM EST TUE JAN 25 2011

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

EAST CENTRAL AND SOUTH FLORIDA
COASTAL WATERS

EFFECTIVE THIS TUESDAY NIGHT FROM 800 PM UNTIL MIDNIGHT EST.

TORNADOES...HAIL TO 0.5 INCH IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 50 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 35 MILES NORTH NORTHEAST OF
WEST PALM BEACH FLORIDA TO 10 MILES SOUTH SOUTHWEST OF NAPLES
FLORIDA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8).

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.

OTHER WATCH INFORMATION...CONTINUE...WW 7...

DISCUSSION...LINE OF SEVERE STORMS CONTINUES TO TRACK EASTWARD
ACROSS THE FL PENINSULA THIS EVENING. LOW LEVEL AND DEEP LAYER
VERTICAL SHEAR REMAINS FAVORABLE FOR EMBEDDED SUPERCELLS ALONG THE
LINE...WITH A RISK OF DAMAGING WINDS AND TORNADOES. LINE IS
EXPECTED TO WEAKEN AND MOVE OFFSHORE BY 05Z.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 0.5 INCH. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
400. MEAN STORM MOTION VECTOR 25035.


...HART

Hazard Tornadoes EF2+ Tornadoes
Likelihood Moderate Low
Severe Wind 65 kt+ Wind
Moderate Moderate
Severe Hail 2"+ Hail
Very Low Very Low


Note: See the experimental Public Watch (SEL) product with explicit hazard information section below. The expiration time in the watch graphic is amended if the watch is replaced, cancelled or extended.
Note: Click for Watch Status Reports.

SEL8

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 8
NWS STORM PREDICTION CENTER NORMAN OK
800 PM EST TUE JAN 25 2011

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

EAST CENTRAL AND SOUTH FLORIDA
COASTAL WATERS

EFFECTIVE THIS TUESDAY NIGHT FROM 800 PM UNTIL MIDNIGHT EST.

ISOLATED TORNADOES
WIDELY SCATTERED DAMAGING WINDS
ISOLATED WIND GUSTS TO 70 MPH POSSIBLE

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 50 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 35 MILES NORTH NORTHEAST OF
WEST PALM BEACH FLORIDA TO 10 MILES SOUTH SOUTHWEST OF NAPLES
FLORIDA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8).

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.

OTHER WATCH INFORMATION...CONTINUE...WW 7...

DISCUSSION...LINE OF SEVERE STORMS CONTINUES TO TRACK EASTWARD
ACROSS THE FL PENINSULA THIS EVENING. LOW LEVEL AND DEEP LAYER
VERTICAL SHEAR REMAINS FAVORABLE FOR EMBEDDED SUPERCELLS ALONG THE
LINE...WITH A RISK OF DAMAGING WINDS AND TORNADOES. LINE IS
EXPECTED TO WEAKEN AND MOVE OFFSHORE BY 05Z.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 0.5 INCH. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
400. MEAN STORM MOTION VECTOR 25035.


...HART

Hazard Tornadoes EF2+ Tornadoes
Likelihood Moderate Low
Severe Wind 65 kt+ Wind
Moderate Moderate
Severe Hail 2"+ Hail
Very Low Very Low


SEL8

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 8
NWS STORM PREDICTION CENTER NORMAN OK
800 PM EST TUE JAN 25 2011

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

EAST CENTRAL AND SOUTH FLORIDA
COASTAL WATERS

EFFECTIVE THIS TUESDAY NIGHT FROM 800 PM UNTIL MIDNIGHT EST.

TORNADOES...HAIL TO 0.5 INCH IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 50 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 35 MILES NORTH NORTHEAST OF
WEST PALM BEACH FLORIDA TO 10 MILES SOUTH SOUTHWEST OF NAPLES
FLORIDA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8).

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.

OTHER WATCH INFORMATION...CONTINUE...WW 7...

DISCUSSION...LINE OF SEVERE STORMS CONTINUES TO TRACK EASTWARD
ACROSS THE FL PENINSULA THIS EVENING. LOW LEVEL AND DEEP LAYER
VERTICAL SHEAR REMAINS FAVORABLE FOR EMBEDDED SUPERCELLS ALONG THE
LINE...WITH A RISK OF DAMAGING WINDS AND TORNADOES. LINE IS
EXPECTED TO WEAKEN AND MOVE OFFSHORE BY 05Z.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 0.5 INCH. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
400. MEAN STORM MOTION VECTOR 25035.


...HART

Hazard Tornadoes EF2+ Tornadoes
Likelihood Moderate Low
Severe Wind 65 kt+ Wind
Moderate Moderate
Severe Hail 2"+ Hail
Very Low Very Low


Note: Click for Watch Status Reports.

WOUS64 KWNS 260055
WOU8

BULLETIN - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH OUTLINE UPDATE FOR WT 8
NWS STORM PREDICTION CENTER NORMAN OK
800 PM EST TUE JAN 25 2011

TORNADO WATCH 8 IS IN EFFECT UNTIL 1200 AM EST FOR THE
FOLLOWING LOCATIONS

FLC011-021-043-051-061-085-093-099-111-260500-
/O.NEW.KWNS.TO.A.0008.110126T0100Z-110126T0500Z/

FL
. FLORIDA COUNTIES INCLUDED ARE

BROWARD COLLIER GLADES
HENDRY INDIAN RIVER MARTIN
OKEECHOBEE PALM BEACH ST. LUCIE


AMZ555-610-650-GMZ656-260500-
/O.NEW.KWNS.TO.A.0008.110126T0100Z-110126T0500Z/

CW

. ADJACENT COASTAL WATERS INCLUDED ARE

SEBASTIAN INLET TO JUPITER INLET 0-20 NM

LAKE OKEECHOBEE

COASTAL WATERS FROM JUPITER INLET TO DEERFIELD BEACH FL OUT 20 NM

COASTAL WATERS FROM CHOKOLOSKEE TO BONITA BEACH FL OUT 20 NM

ATTN...WFO...MFL...MLB...




Hazard Tornadoes EF2+ Tornadoes
Likelihood Moderate Low
Severe Wind 65 kt+ Wind
Moderate Moderate
Severe Hail 2"+ Hail
Very Low Very Low


Note: The Aviation Watch (SAW) product is an approximation to the watch area. The actual watch is depicted by the shaded areas.

SAW8
WW 8 TORNADO FL CW 260100Z - 260500Z
AXIS..50 STATUTE MILES NORTH AND SOUTH OF LINE..
35NNE PBI/WEST PALM BEACH FL/ - 10SSW APF/NAPLES FL/
..AVIATION COORDS.. 45NM N/S /30NNE PBI - 34S FMY/
HAIL SURFACE AND ALOFT..0.5 INCH. WIND GUSTS..60 KNOTS.
MAX TOPS TO 400. MEAN STORM MOTION VECTOR 25035.

LAT...LON 26427987 25298183 26738183 27877987

THIS IS AN APPROXIMATION TO THE WATCH AREA. FOR A
COMPLETE DEPICTION OF THE WATCH SEE WOUS64 KWNS
FOR WOU8.


Watch 8 Status Report Message has not been issued yet.

Member Since: July 15, 2006 Posts: 163 Comments: 52257
Quoting washingtonian115:
Okay folks,ya gotta remember that unlike last year sst in the southern GOM are still warm,and that's one thing that's help fuling those thunderstorms.And to all you floridians stay safe and listn to local officials about warnings,and the latest with the weather.Have your weather emergency kit on hand as well.
My E key is stiff.Sorry.
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Sorry wrong information there.
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Quoting GeoffreyWPB:


It should clear up in the morning.


Thanks, same thing happened last night at this time. :P
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First major cyclone of the year (Category 3 or above)
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Member Since: July 15, 2006 Posts: 163 Comments: 52257

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About JeffMasters

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.