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April 26th-30th, 2014 Major Tornado Outbreak

andyhb

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JoMo

JoMo

Posted
Posted

yeah the 12z NAM doesn't fire much up tonight, there really isn't much overnight as well, while the 12z GFS does have overnight convection developing. That plays a big part in the amount of instability available tomorrow. Wichita and Norman just had a nice AFD update discussing the situation with storms tonight. 

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OceanStWx

OceanStWx

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Norman AFD pretty much all but dismisses the chance for convection tonight. Wichita is more bullish, however. Echoing almost everyone elses thoughts regarding thunderstorm potential this evening.

 

Latest SPC WRF isn't too bullish on convection tonight either. But there is this image for tomorrow...

 

post-44-0-81879700-1398530532_thumb.gif

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soonertrey

soonertrey

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IF indeed there isn't any early morning convection I would think we will see our first high risk outlook of the season by the SPC. I may end up chasing to the OK/AR state line but I probably won't go any further east than that. Just not comfortable chasing in Arky. E OK is bad enough.

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Quincy

Quincy

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I wonder too if the moderate risk gets expanded west. Based on the guidance I'm seeing, especially if we minimize convection tonight, the corridor from E KS to E OK to E TX could really light up quick by early afternoon tomorrow. 

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ZackH

ZackH

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IF indeed there isn't any early morning convection I would think we will see our first high risk outlook of the season by the SPC. I may end up chasing to the OK/AR state line but I probably won't go any further east than that. Just not comfortable chasing in Arky. E OK is bad enough.

 

 

We aren't thrilled about chasing Arkansas either, so we've got our fingers crossed for a greater threat in E KS/W MO, but the signs are hard to ignore for tomorrow. Plus, if things evolve further E into Arkansas the flood plain is actually quite nice to chase in.

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soonertrey

soonertrey

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We aren't thrilled about chasing Arkansas either, so we've got our fingers crossed for a greater threat in E KS/W MO, but the signs are hard to ignore for tomorrow. Plus, if things evolve further E into Arkansas the flood plain is actually quite nice to chase in.

I agree that E AR is easier to chase than W AR. Good luck tomorrow and stay safe.

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andyhb

andyhb

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Sorry for the noob question, but why is convection tonight detrimental to storms tomorrow? 

 

Personally, I think this is becoming less likely further especially south, given the questions of initiation and capping strength, any storms that do form might not make it into the threatened areas for tomorrow.

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jojo762

jojo762

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The satillite image quality on the mesoanalysis page for sector 14 (central plains) is bad at best... Does anybody else have a better website for vis sat images?

EDIT: Also think SPC will expand MDT risk for tomorrow given recent high-res guidance suggesting very little to no evening/overnight convection...

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Quincy

Quincy

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This is NOT the best analog, but it's the "closest" one given the timing and upper level features.

 

Note that tomorrow's setup is a couple hundred miles further south. I think most of us would agree that the threat is not only further south, but more east as well. With that said, if we shift everything about 200 miles SSE, that would still bring some severe up into NE/IA just out in front of the surface low, including a slight tornado risk there as well. 

 

The analog is April 26th, 1991 and I think it's also safe to say that tomorrow's setup looks more intense:
1991042712_024_ptsvr.png

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TropicalAnalystwx13

TropicalAnalystwx13

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DAY 2 CONVECTIVE OUTLOOK   
NWS STORM PREDICTION CENTER NORMAN OK 
1230 PM CDT SAT APR 26 2014 
 
VALID 271200Z - 281200Z 
  
..THERE IS A MDT RISK OF SVR TSTMS ACROSS MUCH OF AR 
SRN 
MO...NRNLA..FAR NERN TX AND EXTREME ERN OK... 
 
...THERE IS A SLGT RISK OF SVR TSTMS OVER A LARGE AREA FROM TX/LA/MS 
NWD INTO NEB AND IA... 
  
..SUMMARY 
 
SEVERE THUNDERSTORMS ARE LIKELY ACROSS MUCH OF THE MISSOURI AND 
MISSISSIPPI RIVER VALLEYS...WITH THE GREATEST THREAT FROM THE 
ARK-LA-TEX INTO SOUTHERN MISSOURI. A SECONDARY THREAT AREA WILL BE 
FROM EASTERN NEBRASKA INTO IOWA. SEVERAL TORNADOES AND VERY LARGE 
HAIL WILL BE POSSIBLE. 
  
..SYNOPSIS 
 
AN UPPER LOW WILL MOVE FROM ERN CO INTO NEB DURING THE DAY WITH A 
NEGATIVELY-TILTED TROUGH AXIS EXTENDING EWD ACROSS THE MIDDLE MO 
VALLEY. AT THE SURFACE...LOW PRESSURE WILL DRIFT SLOWLY EWD ACROSS 
NEBRASKA WITH A DRYLINE NEAR THE NEB/IA BORDER AT 21Z...EXTENDING 
SWD INTO FAR ERN OK AND ACROSS E TX WHERE IT WILL BECOME NEARLY 
STATIONARY. MEANWHILE...A WARM FRONT WILL LIFT NWD ACROSS NERN NEB 
INTO IA. 
 
AHEAD OF THE DRYLINE...SUBSTANTIAL LOW-LEVEL MOISTURE WILL CREATE AN 
UNSTABLE ENVIRONMENT WITH LOWER 60S F DEWPOINTS AS FAR N AS THE IA 
WARM FRONT AND MID TO UPPER 60S F DEWPOINTS FROM ERN OK/AR SWD INTO 
E TX. SHEAR PROFILES WILL STRENGTHEN THROUGH THE PERIOD AND WILL 
FAVOR SUPERCELLS CAPABLE OF TORNADOES AND VERY LARGE HAIL. 
  
..NEB...IA...NERN KS...NWRN MO 
 
SEVERE STORMS ARE EXPECTED TO FORM BY EARLY AFTERNOON AHEAD OF THE 
SURFACE LOW. COLD TEMPERATURES ALOFT AND FAVORABLY ORIENTED 
DEEP-LAYER SHEAR VECTORS ACROSS THE DRYLINE WILL SUPPORT NWD MOVING 
SUPERCELLS CAPABLE OF LARGE HAIL AND A FEW TORNADOES. 
  
..ARKLATEX INTO SRN MO 
 
STRONG INSTABILITY WILL DEVELOP AHEAD OF THE DRYLINE AS MID TO UPPER 
60S DEWPOINTS SURGE NWD AND HEATING OCCURS. DEEP-LAYER SHEAR WILL BE 
PERFECTLY ORIENTED RELATIVE TO THE DRYLINE FOR DISCRETE SUPERCELLS. 
GIVEN THE DEGREE OF BOUNDARY LAYER CONFLUENCE AHEAD OF THE 
DRYLINE...AND STRONG HEATING AND MOISTENING...A PRE-FRONTAL BAND OF 
SUPERCELLS COULD FORM OVER SRN AR...NRN LA...AND NERN TX. SUPERCELLS 
WILL INITIALLY BE CAPABLE OF VERY LARGE HAIL...WITH AN INCREASING 
TORNADO THREAT AS THEY MATURE DURING THE LATE AFTERNOON AND EVENING. 
SEVERAL STRONG TORNADOES APPEAR POSSIBLE...AND A HIGH RISK COULD BE 
ISSUED IN SUBSEQUENT OUTLOOKS ONCE CONFIDENCE IN THE BEST CORRIDOR 
INCREASES. 
 
..JEWELL.. 04/26/2014

 

9yGCJu7.gif

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brettjrob

brettjrob

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This is NOT the best analog, but it's the "closest" one given the timing and upper level features.

 

Note that tomorrow's setup is a couple hundred miles further south. I think most of us would agree that the threat is not only further south, but more east as well. With that said, if we shift everything about 200 miles SSE, that would still bring some severe up into NE/IA just out in front of the surface low, including a slight tornado risk there as well. 

 

The analog is April 26th, 1991 and I think it's also safe to say that tomorrow's setup looks more intense:

 

I definitely wouldn't say tomorrow looks more intense. 4/26/91 is one of the top two or three Plains outbreaks of the past quarter-century, at least; pretty much a benchmark case for the I-35 corridor. That's almost like saying Monday looks more intense than 4/27/11.

 

As for location, at least with respect to the tornado reports on that map, I'd say tomorrow's threat is shifted east by 100 miles or so, but not too much south.

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andyhb

andyhb

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I definitely wouldn't say tomorrow looks more intense. 4/26/91 is one of the top two or three Plains outbreaks of the past quarter-century, at least; pretty much a benchmark case for the I-35 corridor. That's almost like saying Monday looks more intense than 4/27/11.

 

As for location, at least with respect to the tornado reports on that map, I'd say tomorrow's threat is shifted east by 100 miles or so, but not too much south.

 

Regardless of analogs, I think tomorrow could be more dangerous than many Plains setups, given high nocturnal potential and poor terrain.

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Hoosier

Hoosier

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Posted

I definitely wouldn't say tomorrow looks more intense. 4/26/91 is one of the top two or three Plains outbreaks of the past quarter-century, at least; pretty much a benchmark case for the I-35 corridor. That's almost like saying Monday looks more intense than 4/27/11.

 

As for location, at least with respect to the tornado reports on that map, I'd say tomorrow's threat is shifted east by 100 miles or so, but not too much south.

 

 

Yeah, numerous F2 or greater tornadoes with that one with 5 of them being F4/F5.  We're in big trouble if tomorrow is more intense.

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OUGrad05

OUGrad05

Posted
Posted

Man tomorrow is just looking downright nasty for Arkansas.  

 

I'm beginning to be a bit more concerned with Eastern Ok, perhaps even the Tulsa area.  The dryline continues to inch its way further west.  12Z NAM vs the 06Z backs it up another 8 or 10 miles at 4pm.  GFS seems to push it a bit further east between the two runs.  

 

If convection is largely nonexistant tonight that will serve to increase severity tomorrow.  

 

South of I40 in Oklahoma and most of Arkansas are going to get hammered tomorrow.  Anyone chasing in SE OK or W Ar, please use extreme caution, that is some dangerous and rough chase terrain.

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Quincy

Quincy

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I definitely wouldn't say tomorrow looks more intense. 4/26/91 is one of the top two or three Plains outbreaks of the past quarter-century, at least; pretty much a benchmark case for the I-35 corridor. That's almost like saying Monday looks more intense than 4/27/11.

 

As for location, at least with respect to the tornado reports on that map, I'd say tomorrow's threat is shifted east by 100 miles or so, but not too much south.

Just comparing some of the data (using 12z NAM), there are plenty of ways where 4/26/91 looks more intense (greater instability; stronger 0-6km and 0-1km shear), but SRH is comparable, and this time around the surface low is stronger and more consolidated instead of strung out and the 850mb wind field is more expansive, although similar WRT peak winds.

 

Here's a basic comparison:

post-533-0-05874100-1398535428_thumb.gif

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Ed Lizard

Ed Lizard

Posted
Posted

998mb secondary low over north Arkansas by 18z Monday with 2000-3000 joules of SBCAPE all over AR/TN/MS/AL/LA...

 

Really worried about a major tornado outbreak over that region on Monday. 

 

EDIT: SPC-WRF

 

attachicon.gifnam4kmSGP_con_mucape_034.gif

 

attachicon.gifScreenHunter_77 Apr. 26 14.36.png

Just curious, something I might want to post on FB, is there a website for 4 km NAM forecast skew-Ts?

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