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May 24 Plains/MW Severe Threat


Helicity

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I'd be very careful taking these wind profiles at face value though. If we would've done that for 4/27... as late as the 12Z NAM the day of the outbreak, we would've been expecting 0-1 km SRH over Alabama to remain under 250 m2/s2 during peak heating. This bias in the NAM and GFS seems to be one of the most persistent biases that they both have. Use extreme caution with this...

Yep, this bias has been around for years. With the strong isallobaric backing of the surface winds and the intensifying low-level jet associated with the intensification of the low-level cyclone, helicities should soar after 21z. I think the GFS has a better representation of the low-level wind fields right now than the NAM. The GFS depiction right now is scary enough as it is, but it's still probably underestimating helicity.

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I'd be very careful taking these wind profiles at face value though. If we would've done that for 4/27... as late as the 12Z NAM the day of the outbreak, we would've been expecting 0-1 km SRH over Alabama to remain under 250 m2/s2 during peak heating. This bias in the NAM and GFS seems to be one of the most persistent biases that they both have. Use extreme caution with this...

Oh yeah, I know they underdo low-level helicity. But I mean early on in the game, the forecast hodographs look more paltry than usual in most situations. Wouldn't make me forecast a non-event, but it's something to watch out for I suppose.

it is possible the GFS has a better handle on the windfields.

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I've been trying to take these days one at a time here, but due to a very important Bruins game tonight I won't be doing much forecasting. So I've been looking through the available guidance tomorrow, and I really can't add much to what SPC has already said. About as classic as classic can get. A strong LLJ is advertised by both the American models. I'm not at all surprised by talk of a potential high risk.

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MEG is bullish for Wednesday:

THE POTENT UPPER LEVEL LOW PRESSURE SYSTEM TO THE WEST WILL MOVE

INTO THE MID SOUTH ON WEDNESDAY WITH STRONGER MID LEVEL HEIGHT

FALLS. THESE HEIGHT FALLS SHOULD HELP TO FURTHER DESTABILIZE THE

ATMOSPHERE AND ERODE ANY RESIDUAL MID LEVEL CAPPING BY WEDNESDAY

AFTERNOON ALONG AND WEST OF THE MISSISSIPPI RIVER. IMPRESSIVE

STABILITY PARAMETERS DEVELOP WITH SBCAPES BETWEEN 3000-4000

J/KG...LI/S TO -10C...AND MID LEVEL LAPSE RATES GREATER THAN 8

C/KM BY WEDNESDAY AFTERNOON AND EVENING. THIS STRONG INSTABILITY

WILL BE COMPLIMENTED BY INCREASING DEEP LAYER SHEAR ASSOCIATED

WITH A STRONG 80+ KT MID LEVEL JET STREAK EVOLVING ACROSS THE

OZARKS. AT THE SURFACE...LOW PRESSURE WILL DEEPEN ACROSS THE

SOUTHERN PLAINS WEDNESDAY MORNING BEFORE MOVING NORTHEAST INTO

CENTRAL MISSOURI BY WEDNESDAY EVENING. LOW LEVEL SOUTHERLY FLOW

WILL VEER WEST-SOUTHWESTERLY ALOFT AND RESULT IN 0-1KM SRH AROUND

200 M2/S2 BY WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT. AS MID

LEVEL TEMPERATURES COOLIN THE PRESENCE OF STRONG THERMODYNAMIC

INSTABILITY AND STRENGTHENING SHEAR...EXPECT THUNDERSTORMS TO

ERUPT ALONG AND WEST OF THE MISSISSIPPI RIVER BY WEDNESDAY

AFTERNOON. STORM MODE WILL LIKELY INITIALLY BE SUPERCELL

STRUCTURES WITH A THREAT FOR DAMAGING WINDS...LARGE HAIL...AND

TORNADOES. EVENTUALLY THE STRONG FORCING ALOFT WILL ALLOW STORMS

TO CONGEAL INTO A QUASI LINEAR CONVECTIVE SYSTEM (QLCS) WITH

EMBEDDED SUPERCELLS. THE PRIMARY SEVERE WEATHER THREATS WILL

TRANSITION TO MORE DAMAGING WINDS AND LARGE HAIL OVERNIGHT. THIS

THREAT COULD POSE A MORE SIGNIFICANT AND WIDESPREAD SEVERE WEATHER

OUTBREAK OVER THE MID SOUTH WEDNESDAY AFTERNOON AND NIGHT.

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<br class="Apple-interchange-newline">000FXUS63 KICT 231817AFDICTAREA FORECAST DISCUSSIONNATIONAL WEATHER SERVICE WICHITA KS117 PM CDT MON MAY 23 2011.DISCUSSION...FORECAST CONCERN WITH THIS PACKAGE WILL BE POTENTIAL FORSIGNIFICANT SEVERE STORM OUTBREAK ON TUESDAY AND HEAVY RAINISSUES THROUGH WEDNESDAY. STRONG TORNADOES AND LARGE HAIL ARE POSSIBLE.

TUESDAY...COMPLETELY DIFFERENT STORY FOR STORMS ON TUESDAY. THIS MIGHT BE THEBEST SETUP FOR THE AREA IN A WHILE. THE POSSIBILITY FOR LONG TRACKTORNADOES WILL EXIST DURING THIS TIME FRAME.

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Honestly, tomorrow is probably up there among the top 2-3 Plains outbreak setups I've ever seen. I'm trying to recall a Plains setup in the past 50 years or so that was unequivocally better than this one, and I'm coming up empty. We'll have to wait till tomorrow night to see whether this lives up to the potential, but this could be another outbreak of historic magnitude.

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Honestly, tomorrow is probably up there among the top 2-3 Plains outbreak setups I've ever seen. I'm trying to recall a Plains setup in the past 50 years or so that was unequivocally better than this one, and I'm coming up empty. We'll have to wait till tomorrow night to see whether this lives up to the potential, but this could be another outbreak of historic magnitude.

If you were writing a textbook on mesoscale meteorology and had to draw a schematic of a classic plains tornado outbreak setup, it would look exactly like tomorrow. It's petrifying.

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So what your saying is, May 10 2010 is not as bad than this set up, cause I'm not really seeing that as of yet..... but if so then arrowheadsmiley.png

Honestly, i have been having so many ISP problems this week, that I mentally can't take the frustrations of looking at models because they take forEVER to load, I'm talking about 4 minutes a page.....rolleyes.gif

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This has been an incredibly undertalked about set up here across local media in Wichita.

I'm apalled at the "chance of severe tomorrow" Bull sh** they are saying. Last year May 10, 2010 , probably the worst set up I can think of they did a much better job than this, they started talking long track tornadoes 3 days out, but here we are one day out and just a chance of severe tomorrow......

They have got to get the word out here in ICT land that this is not your normal severe weather day, that this is extremely abnormal and everything must be taken with extreme caution.

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Honestly, tomorrow is probably up there among the top 2-3 Plains outbreak setups I've ever seen. I'm trying to recall a Plains setup in the past 50 years or so that was unequivocally better than this one, and I'm coming up empty. We'll have to wait till tomorrow night to see whether this lives up to the potential, but this could be another outbreak of historic magnitude.

I am trying to put this in perspective. The locals here are somewhat on edge after Joplin, but have a long standing and curious NIMBY attitude that the Hillbilly Himalayas (the Ozarks of Carroll and Madison Co.) protects the area from tors. In my job I come in contact with a lot of people on a daily basis, any suggestions on how to forewarn people of this event in a balanced fashion? (the oblivion level here seems way above average)

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The fact that you, CUmet, and others rather well forecasted the intensity of the 4/27 event along with the SPC adverising classic tornado outbreak event has me very worried about the significant number of tornadoes super-cells possible tomorrow. You guys do great advanced analysis.

If you were writing a textbook on mesoscale meteorology and had to draw a schematic of a classic plains tornado outbreak setup, it would look exactly like tomorrow. It's petrifying.

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So what your saying is, May 10 2010 is not as bad than this set up, cause I'm not really seeing that as of yet..... but if so then arrowheadsmiley.png

Honestly, i have been having so many ISP problems this week, that I mentally can't take the frustrations of looking at models because they take forEVER to load, I'm talking about 4 minutes a page.....rolleyes.gif

If the models are going the right direction this will make 5/10/10 look like a cakewalk.

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I normally love severe weather, but tomorrow is not a day I look forward to living in central Oklahoma. I know we are not looking at the sheer numbers of tornadoes we saw in the Southeast during their historic outbreak (hopefully not), but are we looking at the same likelihood of strong/violent tornadoes? To the pro mets, how does the buildup to tomorrow compare to what you were seeing in the days leading up to the Southeast tornadoes?

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Honestly, tomorrow is probably up there among the top 2-3 Plains outbreak setups I've ever seen. I'm trying to recall a Plains setup in the past 50 years or so that was unequivocally better than this one, and I'm coming up empty. We'll have to wait till tomorrow night to see whether this lives up to the potential, but this could be another outbreak of historic magnitude.

If you were writing a textbook on mesoscale meteorology and had to draw a schematic of a classic plains tornado outbreak setup, it would look exactly like tomorrow. It's petrifying.

You guys did a phenomenal job with the April outbreaks and to hear you say that makes me pretty concerned about the tornado situation for tomorrow. Hopefully most of the activity veers away from major cities, but that hasn't been the theme this year...

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I am trying to put this in perspective. The locals here are somewhat on edge after Joplin, but have a long standing and curious NIMBY attitude that the Hillbilly Himalayas (the Ozarks of Carroll and Madison Co.) protects the area from tors. In my job I come in contact with a lot of people on a daily basis, any suggestions on how to forewarn people of this event in a balanced fashion? (the oblivion level here seems way above average)

Remind them of the fact that tornadoes have occurred in mountainous areas. Just think of April 27 and northern Georgia for example. In 1966 people in Topeka believed that a hill called Burnett's mound would protect their city from a tornado. In June of that year an F-5 blasting through town proved otherwise.

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