Europe expected to see a large increase in Hurricane Sandy-like hybrid storms

By: Dr. Jeff Masters , 4:18 PM GMT on April 08, 2013

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Watch out, Europe. Dangerous part-hurricane, part extratropical hybrid storms like Hurricane Sandy of 2012 are expected to be an increasing threat for Western Europe by the end of the century due to global warming, said a team of scientists led by Reindert J. Haarsma of the Royal Netherlands Meteorological Institute. In a paper called "More hurricanes to hit Western Europe due to global warming", published in April 2013 in Geophysical Research Letters, the researchers describe the results from runs of a high-resolution (25 km grid spacing) climate model based on the European Centre for Medium Range Weather Forecasts (ECMWF) numerical weather prediction model. The model predicts that the breeding ground for Atlantic hurricanes will shift approximately 700 miles eastwards as the oceans warm this century. Hurricanes which form farther to the east can spend more time over warm tropical waters before turning north and northeast towards Europe, increasing the odds that these storms will have hurricane-force winds upon arrival in Europe. The model showed that wind shear will change little in the region over the coming decades, resulting in a large increase in storms with hurricane-force winds affecting Western Europe. Most of the these storms will not be tropical hurricanes upon arrival in Europe, but will be former hurricanes that have transitioned to extratropical storms. However, as we saw with Hurricane Sandy of 2012, these hybrid storms can be extremely dangerous. Summed over Norway, the North Sea, and the Gulf of Biscay, the model found that the number of hurricane-force storms in August - October increased from 2 to 13 over the 21st century, with almost all future West European hurricane-force storms predicted to originate as hurricanes or tropical storms in the tropics by 2100. The researchers conclude that "tropical cyclones will increase the probability of present-day extreme events over the North Sea and the Gulf of Biscay with a factor of 5 and 25 respectively, with far reaching consequences especially for coastal safety."


Figure 1. Hurricane Sandy at 10:10 am EDT October 28, 2012. Image credit: NASA/GSFC.

Europe's hurricane history
Only once since accurate records began in 1851 has an actual hurricane with full tropical characteristics hit Europe. This happened on September 16, 1961, when Category 1 Hurricane Debbie hit northwestern Ireland. Wind gusts reached 106 mph at Ballykelly and 104 mph at Tiree and Snaefill, and coastal radio stations reported the airwaves were jammed with calls for help from small ships and fishing craft. Eleven people were killed and 50 injured in the storm. The only other tropical cyclone recorded to have hit Europe since 1851 was Hurricane Vince of 2005, which hit southern Spain as a tropical depression on October 11, 2005. Historical documents also suggest a hurricane hit Spain on October 29, 1842.


Figure 2. Hurricane Debbie of 1961 was the only fully tropical hurricane ever recorded to hit Europe.

Britain's history of ex-hurricane strikes
Hurricanes that transition to powerful extratropical storms hit the British Isles several times per decade, on average. In 2011, Hurricane Katia brushed by Newfoundland, made the transition from a tropical system to a powerful extratropical storm, and maintained strong winds of 50 - 65 mph as it crossed the Atlantic. Ex-Katia hit northern Scotland on September 12, 2011. Glen Ogle, Scotland, at an elevation of 1500 feet (546 meters), received sustained winds of 60 mph, gusting to 86 mph. Cairngorm, in the Scottish Highlands at an elevation of 4085 feet, reported sustained winds of 67 mph. With the trees in full leaf, tree damage was much higher than a winter or springtime storm of similar ferocity would have caused. One person was killed by a falling tree, and heavy tree damage and numerous power failures were reported throughout Britain. Other gusts experienced in Britain included 76 mph at Edinburgh Blackford Hill, 75 mph at Capel Curig in Wales, 72 mph at Glasgow Bishopton, and 71 mph at Loftus, North Yorkshire.


Figure 3. Image of Hurricane Katia taken from the International Space Station at 15 GMT September 9, 2011, by astronaut Ron Garan. At the time, Katia was a Category 1 hurricane with 85 mph winds. Long Island, New York is visible at the lower left.


Figure 4. Surface wind estimate from the Windsat satellite at 4:04 am EDT on Monday, September 12, 2011. The center of Extratropical Storm Katia is marked by an "L", and winds in excess of 50 knots (58 mph, purple triangles) were occurring to the southwest of the center, near the west coast of Ireland. Image credit: NOAA.

As reported by UK Met Office forecaster John Hammond in a post on the BBC 23 degrees blog, Britain has been affected at least eight times in the past twenty years by extratropical storms that were once tropical storms or hurricanes. Before Katia of 2011, the most recent such storm was Hurricane Bill of 2009, which hit Ireland as an extratropical storm on August 25 with sustained winds of 45 mph. Bill was a Category 4 hurricane northeast of the Lesser Antilles five days prior. In 2006, a record three extratropical storms that had once been tropical cyclones hit Britain:

Extratropical Storm Alberto, which had been a strong tropical storm that hit the Florida Panhandle, hit northern Ireland and Scotland as an extratropical storm with 35 mph winds.

Extratropical Storm Gordon hit Ireland on September 21, 2006, with sustained winds of 65 mph. Gordon brought record warm temperatures as tropical air pushed north across the UK, and also strong winds that brought down power lines in Northern Ireland. Wind gusts to 60 mph (97 km/h) occurred in the Isles of Scilly off the southwest coast, and 81 mph (130 km/h) on the mainland.

Extratropical Storm Helene hit Northwestern Ireland on September 27, 2006, with sustained winds of 45 mph.

Figure 5. Path of Hurricane Lili of 1996, which caused $420 million in damage to the U.K. as an extratropical storm.

Other post-tropical cyclones that have the U.K. in the past twenty years include Hurricanes Isaac and Leslie of 2000, Hurricane Karl of 1998, and Hurricane Lili of 1996. The most severe of these storms was Extratropical Storm Lili, which hit Ireland on October 28, 1996, with sustained winds of 65 mph. Lili caused $420 million in damage (2011 dollars) in the U.K. According to Wikipedia, Lili produced a 92 mph (148 km/h) gust at Swansea, South Wales, while bringing a 4' (1.2 meter) storm surge that inundated the River Thames. In Somerset, 500 holiday cottages were severely damaged. A U.S. oil drilling platform, under tow in the North Sea, broke loose during the storm and nearly ran aground at Peterhead. On the Isle of Wight, a sailing boat was beached at Chale Bay; luckily all five occupants were rescued. It was the most damaging storm to have struck the United Kingdom since the Great Storm of 1987, which killed 22 and did $660 million in damage (1996 dollars.) However, Lili also broke a four-month drought over southwest England.

All but one of these storms hit during the peak part of hurricane season, mid-August - late October. The only exception was Ex-Tropical Storm Alberto of 2006, which hit Britain in June.


Figure 6. Hybrid subtropical storm of October 8, 1996, off the coast of Italy. According to Reale and Atlas (2001), the storm had characteristics similar to a hurricane, but formed over cool waters of 21.5°C (71°F.) They reported that "The maximum damage due to wind occurred over the Aeolian Islands, at 38.5°N, 15°E, to the northeast of Sicily: assistance for disaster relief was required. Unfortunately, no weather station data were available, but the media reported sheds, roofs and harbor devices destroyed, and houses and electric lines damaged, due to 'extremely strong westerly wind.' The perfect agreement between the observations at Ustica, the storm scale, the eye-like feature position and the damages over the Aeolian Island reasonably suggest that the hurricane-level intensity of 32 m/s (72 mph) was reached over the Aeolian Islands." A similar hybrid low affected Algeria on 9 - 10 November 2001. This storm produced upwards of 270 mm (10.6") of rain, winds of 33 m/s (74 mph), and killed 737 people near Algiers, mostly from flooding and mud slides. Image credit: Dundee satellite receiving station.

Hurricanes in the Mediterranean Sea?
The Mediterranean Sea between Europe and Africa has experienced several damaging hybrid subtropical storms in recent decades, but has never experienced a fully tropical hurricane in recorded history. However, global warming may cause the Mediterranean to start spawning hurricanes by 2100, according to a 2007 study by a research team led by Miguel Angel Gaertner of the University of Castilla-La Mancha in Toledo, Spain. They ran nine different climate models with resolutions of about 50 km and found that some (but not all) of the models simulated hurricanes in the Mediterranean in September by the end of the century, when ocean temperature could increase by 3°C, reaching 30°C.

Though the Mediterranean may start seeing hurricanes by the end of the century, these storms should be rare and relatively short-lived for three reasons:

1) The Mediterranean is quite far north and is subject to strong wind shear from jet stream activity.

2) The waters are shallow, and have relatively low heat content. There is no deep warm water current like the Gulf Stream.

3) The Mediterranean has a lot of large islands and peninsulas poking into it, increasing the chances that a tropical storm would weaken when it encountered land.

References
Gaertner, M. A., D. Jacob, V. Gil, M. Dominguez, E. Padorno, E. Sanchez, and M. Castro (2007), Tropical cyclones over the Mediterranean Sea in climate change simulations, Geophys. Res. Lett., 34, L14711, doi:10.1029/2007GL029977.

Haarsma et al., 2013, More hurricanes to hit Western Europe due to global warming, Geophysical Research Letters, DOI: 10.1002/grl.50360

Reale, O., and R. Atlas. 2001: Tropical Cyclone-Like Vortices in the Extratropics: Observational Evidence and Synoptic Analysis, Weather and Forecasting, 16, No. 1, pp. 7-34.

Jeff Masters

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Quoting VR46L:


You are gonna wake them up and make them upset
Wake Me Up Before You GoGo......sorry
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Quoting TropicalAnalystwx13:

No. 2010 and 2011 had very active Plains tornado seasons and hardly any hurricanes struck the United States.


I think your getting confused with what I'm tying to say. The years when low numbers of tornadoes have hit Plains seem to have featured major hurricane strikes to the US. Correlation or coincidence?
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My bad...read the question wrong.

Active tornado seasons in the Plains depend solely on the track of upper-level systems during the Spring. The pattern changes frequently and significantly every season, month, and even week.

Placement of tornado activity depends more on the ENSO, and hurricane tracks depend on a multitude of things, but probably not the amount of activity seen in the Plains the previous Spring.

I'll see if I can find some examples.
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Quoting 1900hurricane:

It is exactly as it says incredibly!




Wow!

Quoting Doppler22:


Yes! Storm chance for me finally! and it looks like tomorrow will be more active then today

Looks like a storm chance for me too. I don't know if I will get anything out of it though.
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Nevermind.
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Quoting Tropicsweatherpr:


And both years were very active in the North Atlantic hurricane seasons of those years but maybe nothing related however is a coincidence.


I was just posting that correlation as 2004 and 2005 featured numerous tornadoes being spawn from hurricanes hitting the US while both seasons feature below average tornadoes during tornado season.
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Quoting TropicalAnalystwx13:
The tornado seasons of 2005 and 2010 were very similar to this year thus far; a very quiet -- even quieter than it has been in 2013 -- start followed by a significant ramp-up in activity later in the Spring. Both seasons ended up with over 1,200 tornadoes.

The lack of activity to this point means absolutely nothing.


Most of the tornadoes spawn in 2005 were from hurricanes hitting the US. I wonder if this is setting up to be the case this year. Seems to be a correlation with lower activity tornado wise across the Plains to higher hurricane strike chances during the meat of the hurricane season. Anyone wanna way in on this one?
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This was 10% hatched this morning...

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Yes! Storm chance for me finally! and it looks like tomorrow will be more active then today
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Quoting TropicalAnalystwx13:
The tornado seasons of 2005 and 2010 were very similar to this year thus far; a very quiet -- even quieter than it has been in 2013 -- start followed by a significant ramp-up in activity later in the Spring. Both seasons ended up with over 1,200 tornadoes.

The lack of activity to this point means absolutely nothing.


And both years were very active in the North Atlantic hurricane seasons but maybe nothing related, however is a coincidence.
Member Since: April 29, 2009 Posts: 75 Comments: 13995
Quoting aspectre:
621 Chucktown: Can't wait for that carbon tax to kick in so we can give our U.S. politicians a raise, yet cut back on the NWS.

I'm sure you are trembling with impatience. You're one of those who've written here in support of killing off the NationalWeatherService in favor of "private weather services".
And it's your favored money-worshipping AGW-denialist politicians who are out to gut the NWS.


I don't recall saying that, in fact I'm very much in favor of keeping the NWS "as is". In fact, we work with CHS NWS on a daily basis and have a very informative and well attended Live Chat 24/7, and becomes especially busy when there is severe or tropical weather on the horizon.
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lol....

Tips for live coverage of minimal hurricanes.

1. Wear loose-fitting rain gear, preferably with an open hood to better accentuate wind gusts.
2. Stand with feet sholder width apart and knees bent. Lean torso and head into the direction of the wind for effect.
3. Use minimal wind-screen on microphone, speak loudly as if straining.
4. Position shot to include a fluttering small diameter palm, and a dilapidated structure with flapping corrugated metal.
5. Adjust light filter for gloomy effect.
6. Cut to animated overly-enhanced color radar during lulls.
7. Pan to blowing fronds, leaves and trash if possible.
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Quoting wxchaser97:

Why did they have to cancel spring!? I was looking forward for warm temps and severe weather.

And, since I just got back, this image confuses me, 22F and snowing with a severe thunderstorm warning. I've missed something today...


It is exactly as it says incredibly!



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The tornado seasons of 2005 and 2010 were very similar to this year thus far; a very quiet -- even quieter than it has been in 2013 -- start followed by a significant ramp-up in activity later in the Spring. Both seasons ended up with over 1,200 tornadoes.

The lack of activity to this point means absolutely nothing.
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HPC folks are forecasting a lot of rain from the Mississippi River east.

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Quoting TropicalAnalystwx13:
Good afternoon.

The GFS ensembles continue to be in agreement for below-average temperatures for the latter half of April. Pattern is very similar to what March looked like, with cold air coming out of northwestern Canada and a ridge leading to subsequent warmth across the West.


Why did they have to cancel spring!? I was looking forward for warm temps and severe weather.

And, since I just got back, this image confuses me, 22F and snowing with a severe thunderstorm warning. I've missed something today...

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688. beell
Quoting txjac:


My Godson was there at class and is okay

So, is Houston still on for rain tomorrow? I see all the talk of cap and really dont know how to interpret


Pretty sure we'll see some rain tomorrow afternoon in H town with the front. The cap will be with us until that time.


Cold front is scooting along faster than I thought it would so there probably won't be much opportunity for significant accumulation (less than 1/2"?).
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I've already had some pretty heavy downpours and this part is barely just getting across the lake.

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Member Since: July 15, 2006 Posts: 169 Comments: 53296
Member Since: July 15, 2006 Posts: 169 Comments: 53296
Perfect day at my house today, 74F with lots of Sun! Not record warmth, but way above average.

Looks like Cyclone Imelda is just about to hurricane equivalent strength.

09/1730 UTC 11.7S 59.8E T4.0/4.0 IMELDA -- Southwest Indian

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Check out this forecast.
Member Since: August 9, 2011 Posts: 26 Comments: 8554
Quoting txjac:


My Godson was there at class and is okay

So, is Houston still on for rain tomorrow? I see all the talk of cap and really dont know how to interpret


Houston should do well tomorrow and early Thursday rain wise.

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Good afternoon.

The GFS ensembles continue to be in agreement for below-average temperatures for the latter half of April. Pattern is very similar to what March looked like, with cold air coming out of northwestern Canada and a ridge leading to subsequent warmth across the West.

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Quoting StormTrackerScott:
Very bad year to be storm chasing this year. Oh well I guess a break is welcome after several years of deadly tornado outbreaks.
Bite your tongue. It's only April 9th. That's like saying on August 1, "Pity for us stormwatchers. No land-falling majors for U.S, not this year."
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Quoting txjac:


My Godson was there at class and is okay

So, is Houston still on for rain tomorrow? I see all the talk of cap and really dont know how to interpret

Yup, Houston's still getting rain, although it will probably be frontal rain and not from severe thunderstorms. We'll see though, things will be more clear tomorrow.
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Central US is looking REAL COLD for the next 2 weeks while the eastern US will be well above average.


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rain on the doorstep
Member Since: July 15, 2006 Posts: 169 Comments: 53296
Very bad year to be storm chasing this year. Oh well I guess a break is welcome after several years of deadly tornado outbreaks.
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Very strong cap in place across TX. The only way convection will likely fire is when the cold air comes in and undercuts the warm air.

Notice the winter weather advisories where temps are in the 80's right now across Oklahoma.


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674. txjac
Quoting Doppler22:
i'm not announcing what happened as some of u may already know... but my thoughts go to the victims.... People these days....

Anyway, I see there is no moderate risk anymore, so I guess the CAP may hold up better then previously thought


My Godson was there at class and is okay

So, is Houston still on for rain tomorrow? I see all the talk of cap and really dont know how to interpret
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Thanks for the update, TropicsWeather!

Lindy
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Quoting #662 KEEPEROFTHEGATE:


That model shows a blob with a lot of snow just to my north! We(S WI)are getting some much needed & welcome but cold rain, since yesterday over 1" in the gauge. Let it keep falling from the sky :) I'm waiting to go out in the field and listen to the hay wake up and grow. $6-$8 a bale for hay, ouch! Donkeys will have to go on a diet til the fields green up. J/K.........
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Good afternoon.

A few scattered showers will move thru the NE Caribbean islands tonight and Wednesday.

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE SAN JUAN PR
322 PM AST TUE APR 9 2013

.SYNOPSIS...SURFACE HIGH ACROSS THE WESTERN ATLANTIC WILL BUILD
AND EXPAND EASTWARD OVER THE CENTRAL ATLANTIC DURING THE NEXT FEW
DAYS...MAINTAINING A MODERATE TO FRESH EASTERLY FLOW ACROSS THE
NORTHEAST CARIBBEAN. EASTERLY TRADE WINDS WILL CONTINUE OVER THE
FORECAST AREA THROUGH THE END OF THE WEEK. A MID-UPPER TROUGH WILL
MOVE NORTH OF THE ISLANDS LATE TONIGHT AND WEDNESDAY...DESTABILIZING
SLIGHTLY THE ATMOSPHERE. THIS TROUGH COULD ENHANCE THE AFTERNOON
CONVECTION OVER WESTERN PUERTO RICO ON WEDNESDAY.

&&

.DISCUSSION...VISIBLE SATELLITE IMAGERY INDICATED PARTLY CLOUDY
SKIES AND LIMITED SHOWER ACTIVITY ACROSS MOST OF THE LOCAL ISLANDS...
EXCEPT OVER WESTERN PUERTO RICO WHERE THE TYPICAL AFTERNOON CONVECTION
IS AFFECTING THE WEST AND THE WESTERN INTERIOR. RADAR SHOWED SCATTERED
SHOWERS WITH POCKETS OF HEAVY RAIN AFFECTING SECTIONS FROM RINCON TO
HORMIGUEROS EASTWARD TO ADJUNTAS. MOST OF THESE SHOWERS WILL DISSIPATE
BEFORE SUNSET...LEAVING MOSTLY CLEAR SKIES ACROSS PUERTO RICO AND THE
USVI.

SATELLITE DERIVED PWAT ANALYSIS INDICATED ANOTHER AREA OF DEEPER
MOISTURE APPROACHING THE LESSER ANTILLES. THIS AREA OF MOISTURE IS
FORECAST TO MOVE ACROSS THE USVI OVERNIGHT AND SPREAD OVER PUERTO
RICO WEDNESDAY MORNING. THEREFORE...EXPECT ISOLATED TO SCATTERED
SHOWERS AFFECTING PR/USVI WED MORNING...FOLLOWED BY AFTERNOON
CONVECTION OVER WESTERN PUERTO RICO. SOME ENHANCEMENT IN THE
AFTERNOON CONVECTION IS POSSIBLE TOMORROW DUE TO THE INFLUENCE OF
THE MID-UPPER TROUGH NORTH OF THE LOCAL REGION. IN GENERAL...MODEL
GUIDANCE SUGGESTS A SIMILAR WEATHER PATTERN WITH BANDS OF MOISTURE
EMBEDDED IN THE TRADES REACHING THE FORECAST AREA FROM TIME TO
TIME. THIS WILL RESULT IN A FEW ROUNDS OF SHOWERS ACROSS THE ISLANDS
THROUGH THE END OF THE WEEK.

&&

.AVIATION...LATEST VISIBLE SATELLITE IMAGERY AND DOPPLER WEATHER
RADAR SHOWED SCT-BKN CLD LYRS MAINLY BTW FL020-FL080 WITH EMBEDDED
PASSING SHRA MOVING W ACROSS THE LOCAL FLYING AREA AND BRUSHING
PARTS N AND E COASTAL SECTION OF THE ISLANDS. AFTERNOON CONVECTION
WILL LINGER UNTIL 09/23Z... OVR WRN INTERIOR SECTIONS OF PR. ERLY
WINDS OF 10-25 KTS BLO FL150...BCMG FM W AND INCR W/HT ABV TO MAX
NR 90 KTS NR FL450.

&&

.MARINE...WINDS CONTINUE MODERATE TO FRESH IN RESPONSE TO HIGH
PRESSURE NORTH OF THE AREA CONTINUING THROUGH THE WEEKEND. THIS
WILL KEEP SEAS BETWEEN 5 TO 6 FOOT WITH PERIODS BETWEEN 8 TO 10
SECONDS. SEAS ARE EXPECTED TO REMAIN BELOW THE SCA CRITERIA MOST
OF THE WEEK.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 76 88 75 86 / 30 30 30 30
STT 76 85 76 86 / 20 30 30 30
Member Since: April 29, 2009 Posts: 75 Comments: 13995
Quoting redwagon:


What temps were you needing for cap-busting in Austin you wrote about earlier? We're surrounded here by 80os
here and even a 100o reading on the border. Is it possible to erode the cap from the outside in?

I'm sorry to be so whiny.. just that NAM served us up 2-3" a few days ago and then yanked it like Jason Biggs.

Based on the current RUC sounding, temps will have to exceed about 110*F in order to break the cap alone.



However, as the upper level disturbance approaches, the cap will begin to weaken, but I don't expect it will weaken enough to ignite storms along the Balconies before the cold front arrives and undercuts any potential surface based instability.
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Quoting louisianaboy444:
I feel sorry for any chasers this spring it looks to be a lost cause....Thats why I'm glad I chase hurricanes but even that department has been boring the past couple of years! Who turned on the boring weather button :)

FYI: In terms of Gulf Coast storms...I felt I needed to post this before I get a 1000 comments freaking out saying "Sandy! What about Sandy!"


I'm still chasing the remnants of Nadine. It's all good :)
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They come, they complain, but they never post any verifiable, factual data.
I suppose most of them will claim this is just another government lie.

Ice volume is a better Gage of the problem, but this one is a good indicator of the "new normal".

Another graph that should be a sticky.

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i'm not announcing what happened as some of u may already know... but my thoughts go to the victims.... People these days....

Anyway, I see there is no moderate risk anymore, so I guess the CAP may hold up better then previously thought
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666. beell


MESOSCALE DISCUSSION 0411
NWS STORM PREDICTION CENTER NORMAN OK
0214 PM CDT TUE APR 09 2013

AREAS AFFECTED...NWRN TX INTO MUCH OF CNTRL OK

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 091914Z - 092115Z

PROBABILITY OF WATCH ISSUANCE...80 PERCENT

SUMMARY...SCATTERED STORMS WILL EVENTUALLY FORM AND LARGE HAIL WILL
BE POSSIBLE. A WATCH MAY BE REQUIRED BEFORE 21Z.

DISCUSSION...AN ARCTIC FRONT CONTINUES TO SURGE SWD ACROSS TX INTO
WRN OK. ALONG THIS FRONT...OCCASIONAL CU HAVE RAPIDLY DEVELOPED AND
DISSIPATED AS SOURCE AIR GETS UNDERCUT. AHEAD OF THE FRONT...THE AIR
MASS HAS BEEN CAPPED.

HOWEVER...LATEST VISIBLE IMAGERY INDICATES CHANGING CHARACTER TO THE
CU FIELDS FROM NWRN TX INTO WRN OK NEAR THE FRONT. A DEEPER GROUPING
OF TCU HAS FORMED ON THE NOSE OF THE HOTTER AIR ACROSS NWRN
TX...NEAR A WEAK SURFACE LOW AND DRYLINE/COLD FRONT INTERSECTION
WHERE CAPPING IS NEGLIGIBLE. MORE RECENTLY...STABLE WAVE CLOUDS HAVE
MIXED ACROSS W CNTRL AND SWRN OK...SUGGESTING THE CAP IS BEING
LIFTED THERE AS WELL. WITH ADDITIONAL SURFACE HEATING AHEAD OF THE
FRONT...AND COOLING IN THE CAPPING LAYER...STORM INITIATION WILL
BECOME INCREASINGLY LIKELY OVER THE NEXT COUPLE HOURS.

ONE POTENTIAL PROBLEM IN REGARD TO LONG LIVED SEVERE CONVECTION IS
THE TENDENCY FOR THE FRONT TO UNDERCUT DEVELOPMENT OCCURRING ALONG
IT...ORPHANING THE INCIPIENT UPDRAFTS. THEREFORE...MUCH OF THE
CONVECTION MAY END UP BEING ELEVATED BEHIND THE FRONT.

..JEWELL/THOMPSON.. 04/09/2013
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665. HadesGodWyvern (Mod)
Tropical Cyclone Warning Center Perth
Tropical Cyclone Advisory
TROPICAL CYCLONE VICTORIA, CATEGORY TWO (17U)
2:49 AM WST April 10 2013
========================================

At 2:00 AM WST, Tropical Cyclone Victoria (988 hPa) located at 14.1S 103.4E has 10 minute sustained winds of 55 knots with gusts of 75 knots. The cyclone is reported as moving south southeast at 10 knots.

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

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

Dvorak intensity: T4.4/4.0/D2.0/24 HRS

Forecast and Intensity
=======================
12 HRS: 15.4S 104.0E - 60 knots (CAT 2/Tropical Cyclone)
24 HRS: 16.7S 104.7E - 55 knots (CAT 2/Tropical Cyclone)
48 HRS: 20.1S 105.5E - 35 knots (CAT 1/Tropical Cyclone)
72 HRS: 25.3S 106.0E - 30 knots (Tropical Low)

Additional Information
=======================
Tropical Cyclone Victoria has continued to develop over open waters, well away from Cocos and Christmas Islands.

TC Victoria has developed rapidly overnight. ASCAT passes from 1422UTC and 1515UTC show maximum winds around 55 knots near the centre. DT is 3.5 based on a shear pattern [constraints do not allow for the use of an embedded center pattern, which would yield a higher number]. MET is 3.5 based on rapid development, and PAT is 4.0. FT and CI are set at 4.0. ADT has been giving raw T numbers of around 3.7. SATCON has the intensity at around 55-60 knots. A SSMI microwave image from 1121UTC shows a tight circulation around the system centre, with indications of a possible eye forming. Intensity is set at 55 knots.

TC Victoria was located using microwave and satellite imagery as well as the ASCAT passes.

CIMSS shear between 1200UTC and 1800UTC was around 10-15 knots from the north northeast. However, as the system is moving south at around 10 knots, system-relative shear is low.

Sea surface temperatures and Ocean Heat Potential are conducive for development and there is good poleward outflow due to an approaching upper level trough. Conditions should remain favorable for the next 24 hours or so. There is a possibility that the system could reach Category 3 intensity during Wednesday, but at this stage the forecast is for the system to peak at 60 knots.

Late Wednesday and particularly Thursday, northwest wind shear is forecast to increase. The increasing wind shear, lower sea surface temperatures and drier air in the mid-levels should weaken the system. As the cyclone is small, weakening should occur rapidly when it does commence.

General south to southeast motion is expected under the influence of an upper level ridge to the east and an approaching upper level trough.

The system is not expected to impact Cocos or Christmas Island or the Western Australian mainland. Moderate to heavy rainfall and squally conditions are possible over Christmas Island until Thursday in the monsoonal flow to the north of the cyclone.
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664. HadesGodWyvern (Mod)
Mauritius Meteorological Services
Tropical Cyclone Advisory #16
FORTE TEMPETE TROPICALE IMELDA (10-20122013)
22:00 PM RET April 9 2013
======================================

At 18:00 PM UTC, Severe Tropical Storm Imelda (973 hPa) located at 11.6S 59.7E has 10 minute sustained winds of 60 knots with gusts of 85 knots. The cyclone is reported as moving west at 6 knots.

Storm Force Winds
=================
50 NM radius from the center

Gale Force Winds
=================
80 NM radius from the center, extending up to 90 NM in the northeast quadrant and up to 100 NM in the southern semi-circle

Near Gale Force Winds
====================
130 NM radius from the center, extending up to 150 NM in the northeastern quadrant, and up to 160 NM in the southern semi-circle

Dvorak Intensity: T4.0/4.0/D0.5/12 HRS

Forecast and Intensity
=======================
12 HRS: 11.8S 58.6E - 70 knots (Cyclone Tropical)
24 HRS: 12.5S 57.9E - 80 knots (Cyclone Tropical)
48 HRS: 14.5S 58.2E - 90 knots (Cyclone Tropical Intense)
72 HRS: 16.7S 58.6E - 85 knots (Cyclone Tropical)

Additional Information
=========================
Regular intensification continues. Over the past six hours, the speed of the system seems to decreased.

The system keeps on tracking westwards on the northern edge of the subtropical ridge in the low/mid levels.

Within the next 12-18 hours system is expected to slow down over a west southwestwards then southwestwards track. On and after 24-30 hours, the steering flow should turn north northwesterly under the influence of a mid-tropospheric ridge building northeast of the system and of a trough southward. Then system should re-curve south southeastward. On and after Wednesday, most of the deterministic numerical weather prediction models and ECMWF ensemble prediction system are in good agreement to this meridian track but the spread is yet relatively large. The official track of the RSMC is close to ECMWF.

On this forecast track, upper levels conditions should become very favorable with good outflows especially southward. Sea surface temperatures are favorable over all the forecast period. System should therefore intensify regularly until Thursday. On and after Friday it may begin a slow weakening phase.
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Quoting 1900hurricane:
Really interesting case of some elevated convection in Nebraska!



Looks pretty run of the mill... until you see the radar with the winter algorithms on!



Surface obs showing temps below freezing in the area in question.



And RAP soundings reinforce that same idea, showing a shallow arctic airmass undercutting the existing airmass. With seep lapse rates above the front, the frontal forcing is kicking off convection, which is taking advantage of the elevated CAPE.



What temps were you needing for cap-busting in Austin you wrote about earlier? We're surrounded here by 80os
here and even a 100o reading on the border. Is it possible to erode the cap from the outside in?

I'm sorry to be so whiny.. just that NAM served us up 2-3" a few days ago and then yanked it like Jason Biggs.
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Member Since: July 15, 2006 Posts: 169 Comments: 53296
Member Since: July 15, 2006 Posts: 169 Comments: 53296
SPC taking note too.



MESOSCALE DISCUSSION 0410
NWS STORM PREDICTION CENTER NORMAN OK
1230 PM CDT TUE APR 09 2013

AREAS AFFECTED...NW KS...S-CNTRL/CNTRL NEB

CONCERNING...WINTER MIXED PRECIPITATION

VALID 091730Z - 092130Z

CORRECTED FOR INCORRECT GEOGRAPHICAL REFERENCE IN THE HEADER.

SUMMARY...SHOWERS...WITH EMBEDDED CONVECTIVE ELEMENTS...ARE EXPECTED
TO CONTINUE WHILE LIFT OVER THE COLD FRONT PERSISTS. UNCERTAINTY
EXISTS REGARDING PRECIPITATION TYPE AS WELL AS PRECIPITATION RATES
BUT FREEZING RAIN RATES IN EXCESS OF 0.05 INCH/HR ARE POSSIBLE.

DISCUSSION...A STRONG...SHALLOW COLD FRONT CONTINUES TO SURGE ACROSS
THE SRN/CNTRL PLAINS. 17Z SURFACE ANALYSIS PLACES THE FRONT FROM
JUST N OF LBB NEWD ACROSS FAR NW OK TO FNB /IN EXTREME SE NEB/. DEEP
LAYER FLOW IS ORIENTATED NEAR-PARALLEL TO THE FRONTAL
BOUNDARY...FAVORING THE CONTINUED ADVECTION OF MOISTURE INTO THE
COLD AIR BEHIND THE FRONT. ADDITIONALLY...MESOANALYSIS REVEALS
ELEVATED INSTABILITY EXTENDING AS FAR N AS THE NEB/SD BORDER. WHILE
CONSIDERABLE UNCERTAINTY EXISTS REGARDING PRECIPITATION TYPE
/PRIMARILY DUE TO THE UNCERTAINTY REGARDING THE DEPTH OF THE COLD
AIR AND CONTINUED MODIFICATION OF THE WARM NOSE/...SOME FZRA IS
ANTICIPATED...WITH RATES EXCEEDING 0.05 IN/HR POSSIBLE. BRIEF HEAVY
SNOW AND SLEET ARE ALSO POSSIBLE.

..MOSIER.. 04/09/2013


ATTN...WFO...OAX...GID...LBF...GLD...

LAT...LON 39309965 38980058 39210103 39600142 40070143 40510132
41380041 42519864 42609755 42009748 39309965
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Member Since: July 15, 2006 Posts: 169 Comments: 53296
Member Since: July 15, 2006 Posts: 169 Comments: 53296
Really interesting case of some elevated convection in Nebraska!



Looks pretty run of the mill... until you see the radar with the winter algorithms on!



Surface obs showing temps below freezing in the area in question.



And RAP soundings reinforce that same idea, showing a shallow arctic airmass undercutting the existing airmass. With seep lapse rates above the front, the frontal forcing is kicking off convection, which is taking advantage of the elevated CAPE.

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The Arctic still melting at an alarming rate. The thickest ice keeps breaking apart.




It's trying its hardest to look like the first ice free summer. Link below of the 12 month animation below.

Link
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FROPA=Frontal passage

(edit. MTWX quote removed.)
The cap will give way in SW OK and N TX at least, and early enough. Perhaps further N along the dryline. This I surmise from observations at my location in central OK.

Crapshoot whether cold front already draped SW to NE across far NW OK will beat out the dryline action, but I tend to agree we'll see a couple three dryline supercells with potential tornadic action most likely springing to life in N TX/SW to Scentral. Just my guess. Could be big hail and ice rain tonight will be the big story.



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Oh, sorry.
I ordered the boring weather to help me catch up on other work and pump up the volume on surface waters. Gambling on a few tropical storms instead of heavy afternoon showers, has not been paying off for Florida lately.
Did you want the exiting weather back now? I just need 9 more inches in east central Florida, then you can have your excitement. Should take about 2 weeks? 2 months?
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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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