Tornadoes, huge hail pound the Midwest, but bring little Texas drought relief

By: Dr. Jeff Masters , 12:41 PM GMT on April 20, 2011

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Severe weather blasted the Midwest again yesterday, with NOAA's Storm Prediction Center logging 32 reports of tornadoes, 399 reports of damaging thunderstorm winds, and 325 instances of large hail (including softball-sized hail of 4.25 - 4.5" diameter in Clarkesville, MO and Stringtown, OK.) Fortunately, no deaths or injuries were reported from yesterday's storms. The storm also brought the heaviest snow so late in the season to Green Bay, Wisconsin--9.9 inches. This brought the seasonal total for Green Bay to 92.4", the third most on record.

The storm responsible will trek eastwards today, bringing the threat of severe weather to regions of the Southeast hard-hit by last week's remarkable tornado outbreak. NOAA's Storm Prediction Center has placed a wide swath of the country from Eastern Texas to New Jersey under their "slight risk" for severe weather. According to the latest tornado tallies on the excellent Wikipedia page on the April 14 - 16 tornado outbreak, 128 tornadoes are confirmed to have occurred, with 39 of these strong EF-2 and EF-3 twisters. Remarkably, there have been no violent EF-4 or EF-5 tornadoes reported yet in 2011, despite the fact that the preliminary 2011 tornado count as compiled by SPC is 611, which will likely make 2011 the most active tornado season on record for this point in the year.


Figure 1. Satellite image taken at 8pm EDT on Tuesday, April 19, 2011, of the storm system that brought severe weather to the Midwest. Image credit: NASA/GSFC.


Figure 2. Severe weather outlook for today.

Yesterday's storms bring little drought relief for Texas
Yesterday's severe weather outbreak brought a few thunderstorms to the Dallas/Fort Worth area last night, with up to two inches of welcome rain falling in isolated areas. However, the rains missed the areas of Texas where the worst fires area burning, and strong winds associated with the spring storm helped whip up the fires. Winds will not be as strong today, and the latest 1 - 5 day rainfall forecasts show the possibility of isolated thunderstorms bringing drought relief to the same portions of Texas that benefited from last night's rains. These rains will not be enough to significantly slow down the record fires scorching Texas, though, and the latest 2-week forecast from the GFS model shows little chance of drought-busting rains over Texas into early May.


Figure 2. Total rainfall for North Texas from last night's storms brought only isolated drought relief.

Atlantic tropical disturbance
As a reminder that hurricane season is not that far away, an area of disturbed weather has formed in the Atlantic near 23N, 80W, about 700 miles northeast of Puerto Rico. This system is under a hefty 60 knots of wind shear, but does have a surface circulation. The disturbance's heavy thunderstorm activity has been removed well to the northeast of the surface circulation center by the high wind shear. The storm is expected to move northwest into a region of lower wind shear on Thursday and Friday, and should begin building more heavy thunderstorms during the next three days. The storm is not a threat to any land areas, and will likely be ripped apart by high wind shear this weekend. It has perhaps a 10% chance of becoming a subtropical depression before then. Climatology argues against this storm becoming the first named storm of the year; there has only been once named April storm in the Atlantic since 1851, Tropical Storm Ana of 2003.


Figure 4. Morning satellite image of the Atlantic tropical disturbance 700 miles northeast of Puerto Rico.

Jeff Masters

Wildcat Fire (AngeloJoe)
Wildcat Fire near San Angelo, Texas. Pictures taken between 3 and 4 pm just to the south and east of Orient, Texas.
Wildcat Fire
April Showers (novembergale)
SNOW showers!
April Showers

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Quoting EYEStoSEA:


That is good to see....here's wishing it will spread over a large area.....maybe it is a sign of more rain to come.....hopefully


Thanks Eyes! From your mouth to God's ears!
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590. JLPR2
Quoting KEEPEROFTHEGATE:
if ya look ddc in image ya see two eyes and open mouth that looks to be sayin WTF this is april


Haha, yeah, way too early, makes you wonder how the rest of the season is going to be...
But I believe I read somewhere that an active early season doesn't mean its going to be active during the reast of it. I think... XD
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earlier
Member Since: July 3, 2005 Posts: 424 Comments: 128345
Quoting pottery:

Sad, that.
Embarrassing as well, I should imagine.
if anything its a nice test run
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Quoting Grothar:
Nice link of the system, if it comes through. Seems all of the sites are having a little trouble.

Just click the IR-NHC button on top to see the image.


Link


Grothar, that IS a good link....have saved..TY :)
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Quoting JLPR2:
RAMSDIS has a floater on 91L

Link

I see it spinning, but not much in terms of convection.
if ya look ddc in image ya see two eyes and open mouth that looks to be sayin WTF this is april
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Quoting iflyu2:
Finally! The first two storms of the season for us in south texas are finally visable on the Brownsville Nexrad this evening. Looks like Monterrey might get a little rain tonight but none for us. Glad I'm not flying tonight. Ice (cloud temps reported at -55C), hail (up to 2 inches) and wind shears are not a good mix with turbo-props. Here in McAllen we could use a little rain, though. Guess I picked the wrong year to put in new sod! HaHa!


That is good to see....here's wishing it will spread over a large area.....maybe it is a sign of more rain to come.....hopefully
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584. JLPR2
RAMSDIS has a floater on 91L

Link

I see it spinning, but not much in terms of convection.
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Quoting KEEPEROFTHEGATE:
XX/INV/91L
MARK
23.69N/60.11W




POSS COC COLLAPSE

Sad, that.
Embarrassing as well, I should imagine.
Member Since: October 24, 2005 Posts: 0 Comments: 24314
REQUIREMENTS FOR Tropical Cyclone Formation Alert

If a system gets 35 to 38 points, a TCFA may be issued depending on Dvorak trends, and if a system gets 39 points or more a TCFA should be issued.

Surface
Condition Points
A circulation is evident using visible satellite, shortwave infrared, microwave imagery or QuikSCAT/Windsat ambiguities 3 points
A circulation has been evident for at least 24 hours 5 points
A westerly surface- or gradient-level wind of 5 kt that is within 200 nm (370 km, 230 mi) south of the centre of the disturbance 5 points
Any wind associated with the system is at least 20 kt 2 points
Any wind associated with the system is at least 25 kt 3 points
Any wind associated with the system is at least 30 kt 4 points
A weather station within 200 nm of the system has reported had a pressure drop of 2 mb over 24 hours 3 points
A weather station within 200 nm of the system has had a pressure drop of 3 mb over 24 hours 4 points
The estimated MSLP of the system is less than 1010 to 1009 mb 3 points
The estimated MSLP of the system is 1008 mb or less 4 points

500 mb height
Condition Points
There is evidence of at least an inverted trough 2 points
There is evidence of a closed circulation in the system 4 points

200 mb height
Condition Points
Westerly flow of at least 15 kt over the disturbance -4 points
There is evidence of anticyclonic outflow over the centre of the disturbance 4 points
Easterly flow of at most 20 kt over the disturbance 3 points

Sea surface temperature
Condition Points
The sea surface temperature is 26 Celsius (78.8 Fahrenheit) or higher 3 points

Satellite data
Condition Points
The system has persisted for at least 24 hours 3 points
The system has persisted for at least 48 hours 4 points
The system has persisted for at least 72 hours 5 points
The system has a Dvorak classification of T1.0 to T1.5 from all three agencies (TAFB, SAB, AFWA) 3 points
The system has a Dvorak classification of T1.5 to T2.0 from all three agencies 5 points
The Dvorak final-T number has decreased by T0.5 to T1.0 from two or more agencies -2 points

Miscellaneous
Condition Points
The cloud system is north (or south) of 5 degrees latitude 3 points
The tropical system is within 72 hours of reaching a Department of Defense resource 3 points
The cloud system center and the satellite centre fixes for the system are within 2 degrees of each other 2 points
************************************************* *********
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Finally! The first two storms of the season for us in south texas are finally visable on the Brownsville Nexrad this evening. Looks like Monterrey might get a little rain tonight but none for us. Glad I'm not flying tonight. Ice (cloud temps reported at -55C), hail (up to 2 inches) and wind shears are not a good mix with turbo-props. Here in McAllen we could use a little rain, though. Guess I picked the wrong year to put in new sod! HaHa!
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Quoting Grothar:


Very objective observation.


It is. It eliminates any toying with other subjective interpretations. If it's non-frontal, over tropically-warm water, has a closed circulation with gales, then it deserves a name based on the accepted criteria.
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All NOAA Tropical Floater Imagery
Member Since: July 3, 2005 Posts: 424 Comments: 128345
XX/INV/91L
MARK
23.69N/60.11W




POSS COC COLLAPSE
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Nice link of the system, if it comes through. Seems all of the sites are having a little trouble.

Just click the IR-NHC button on top to see the image.


Link
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Quoting Levi32:
And now here come the times of debating criteria for these kinds of systems. If we were doing this the simple way, it has a closed circulation over >25C water with gales on the north side, and therefore deserves a subtropical name. However, the NHC insists on making the naming criteria for subtropical cyclones very subjective.


Very objective observation.
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And here is the NHC's definition of a subtropical cyclone:

Subtropical Cyclone:
A non-frontal low pressure system that has characteristics of both tropical and extratropical cyclones. This system is typically an upper-level cold low with circulation extending to the surface layer and maximum sustained winds generally occurring at a radius of about 100 miles or more from the center. In comparison to tropical cyclones, such systems have a relatively broad zone of maximum winds that is located farther from the center, and typically have a less symmetric wind field and distribution of convection.

The fact is that there are no fronts (if there is any frontal zone it is removed northeast of the center at this point), and it has a closed circulation with gale-force winds that are actually near the center, more organized than most subtropical entities.

So the question becomes, what is preventing its classification? Likely consistency and duration at this point, as the NHC likes to sit on these things for 12-24 hours before classifying them, and even then they sometimes don't seem to follow their own criteria, so we'll see.
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574. beell
Quoting EYEStoSEA:


Thank You, Beell....I see..BTW..your blog is on my favorite blogs list...I read a lot..:)


YW, EYES. There is a WUnderful world here to browse through. Always something to catch your eye/curiosity/imagination/anger/laughter/sorrow/et c/etc
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And now here come the times of debating criteria for these kinds of systems. If we were doing this the simple way, it has a closed circulation over >25C water with gales on the north side, and therefore deserves a subtropical name. However, the NHC insists on making the naming criteria for subtropical cyclones very subjective.
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Quoting Levi32:


It's unlikely it would be able to combat the shear in the Gulf of Mexico if it were to get there.
it will ramp up then ramp down towards sw then meander for a bit as areas of rain
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Quoting PlazaRed:


Thanks very much to Everybody for their comments and information imparted.

3am, in Europe and although all is very exciting, Hasta Manana. y Que Sera Sera, { What will be, will BE!}


Goodnight....mean morning, Plaza...sleep well...
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Quoting Levi32:


It's unlikely it would be able to combat the shear in the Gulf of Mexico if it were to get there.


Thanks very much to Everybody for their comments and information imparted.

3am, in Europe and although all is very exciting, Hasta Manana. y Que Sera Sera, { What will be, will BE!}
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Quoting PlazaRed:


With all due respects.

If this little Dr. Jekyll fellow wanders over to the tepid gulf then it might grow into a bit of a Mr. Hyde.
Then again the strict 'administrators of sheer,' might just call the Deuce?


It's unlikely it would be able to combat the shear in the Gulf of Mexico if it were to get there.
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18z GFS and 18z UKMET both initialized 91L as shallow warm-core:



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Quoting Levi32:


It's not yet tropical, and it likely will only be able to acquire shallow warm-core charactistics and be subtropical, but not fully tropical. Subtropical cyclones do not rely fully on tropical processes and thus don't have to draw as much energy from the ocean to sustain themselves. Thus, the 26C rule is generally lowered to about 23C for subtropical cyclones.


With all due respects.

If this little Dr. Jekyll fellow wanders over to the tepid gulf then it might grow into a bit of a Mr. Hyde.
Then again the strict 'administrators of sheer,' might just call the Deuce?
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It's rather impressive that the wind max associated with 91L is actually fairly close to the center, unlike most subtropical lows.

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Quoting beell:


More moisture, less windshear.


Thank You, Beell....I see..BTW..your blog is on my favorite blogs list...I read a lot..:)
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Not much help in Texas, just hot and dry. From Austin-San Antonio discussion:

Expect convection to lose its punch after sunset with loss of heating. Just slight chances for thunder will persist through the midnight hour before the boundary begins to lift northward away from US...taking focus with it. Some low stratus will develop over much of the area around and after midnight...helping to keep temperatures a good ten to fifteen degrees above normal overnight.


The rest of the forecast is much less exciting as ridging builds in and the cap strengthens. GFS brings in a weak wave early next week...but timing and strength are still very much in question so will favor ongoing forecast for continuity. The pattern of well above normal temperatures appears likely to continue well into next week.
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91L Multiplatform Satellite Surface Wind Analysis
Member Since: July 3, 2005 Posts: 424 Comments: 128345
Quoting Levi32:


It's not yet tropical, and it likely will only be able to acquire shallow warm-core charactistics and be subtropical, but not fully tropical. Subtropical cyclones do not rely fully on tropical processes and thus don't have to draw as much energy from the ocean to sustain themselves. Thus, the 26C rule is generally lowered to about 23C for subtropical cyclones.
Thanks
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Note the 5 new names as this years list lost 5 to retirement 6 years ago.

Dennis
Katrina
Rita
Stan
Wilma
Member Since: July 3, 2005 Posts: 424 Comments: 128345
Quoting gulfbreeze:
How can 91L be tropical in 74 degree water?


It's not yet tropical, and it likely will only be able to acquire shallow warm-core charactistics and be subtropical, but not fully tropical. Subtropical cyclones do not rely fully on tropical processes and thus don't have to draw as much energy from the ocean to sustain themselves. Thus, the 26C rule is generally lowered to about 23C for subtropical cyclones.
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Quoting sammywammybamy:


Nice Diagram.

Thank you!
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Here are the names for this season:

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Quoting snotly:
The researchers scoured data from passive microwave satellites from 1987 to 2008 to see how hurricanes behaved in the 24 hours before a storm underwent rapid intensification. Such a big-picture approach, in contrast to the case studies atmospheric scientists often perform, revealed clear patterns in storm dynamics. They found that, consistently, low-shear storm systems formed a symmetrical ring of thunderstorms around the center of the system about six hours before intensification began. As the system strengthened into a hurricane, the thunderstorms deepened and the ring became even more well-defined.

Link


Interesting. And needed. The more we know about these things and the quicker the better. :)
Member Since: August 24, 2010 Posts: 0 Comments: 161
Quoting PlazaRed:


EYES!!

Look back over this last 50 or so posts and there are 2 things you will see.

''1,'' nobody has had had any form of fight, or major disagreement and all as been in good fun as much as we can portray, the fact that there have been 2 significant storm invests in the North Atlantic in the months of March and April. all its implications will be a game for the Wrath's.

The second thing which we will call ''2,'' is that the people who know more than we can ever hope to grasp have been only too forthcoming with their knowledge, in order that we can grasp the enormity of the global weather situation. Thanks to all of them.
{Keeper, Sammy, Jeff's Doc,and all the others who know.}


Yes, I'm aware of the knowledge here, for sure....best place to be during the season....at the time I posted the question, blog was very slow...and I was studying the sattelite....., but never fear...I'm learning...always :) TY Plaza
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How can 91L be tropical in 74 degree water?
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Quoting sammywammybamy:


And the shallow layer steering currents will take it where?

Central Cuba.

PSU e-WALL Steering Layers
Member Since: September 2, 2009 Posts: 130 Comments: 21193
548. beell
Quoting EYEStoSEA:
Ok. ..someone jump on this question, now is a good time for me to learn....As I stare at the visuals of this 91L.....what is it I'm looking for to make it so? Know a little about earthquakes, more about tornadoes......but AOI's, invests, not so much....


More moisture, less windshear.
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Quoting EYEStoSEA:
Ok. ..someone jump on this question, now is a good time for me to learn....As I stare at the visuals of this 91L.....what is it I'm looking for to make it so? Know a little about earthquakes, more about tornadoes......but AOI's, invests, not so much....


EYES!!

Look back over this last 50 or so posts and there are 2 things you will see.

''1,'' nobody has had had any form of fight, or major disagreement and all as been in good fun as much as we can portray, the fact that there have been 2 significant storm invests in the North Atlantic in the months of March and April. all its implications will be a game for the Wrath's.

The second thing which we will call ''2,'' is that the people who know more than we can ever hope to grasp have been only too forthcoming with their knowledge, in order that we can grasp the enormity of the global weather situation. Thanks to all of them.
{Keeper, Sammy, Jeff's Doc,and all the others who know.}
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Quoting sammywammybamy:


Whats your Opinon?

Ive already stated mine:

91L becomes a Sub tropical depression then gets ripped apart with Shear bringing showers to S. and C. Florida for a Day or two.
I see a small window of opportunity for development between 36 and 60 hours as depicted by the 12z ECMWF. After 60 hours the system will probably move/drift towards the west or southwest given it weakens (due to a very sharp increase in upper-level winds) and follows the shallow layer steering currents.
Member Since: September 2, 2009 Posts: 130 Comments: 21193
18z GFDL is interesting, if not a little wacky with the path, but maintains a weak intensity throughout.
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Quoting MiamiHurricanes09:
Interesting...not buying it though.


Actually, I think that's defiantly a possibility if all the conditions work right.
Member Since: July 8, 2005 Posts: 259 Comments: 24040

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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.