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2014 Short Term Severe Weather Disco


Chicago Storm

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There were several ASOS locations with 80-82 dew points today. Madison SD had a dew point of 81 for several hours. Valley City ND is currently 82/82 (100% relative humidity). Yuck. Offutt Air Force Base (Omaha) has a dew point of 84.  This is one of the most impressive days for dew points that I have seen.

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just was looking at the 00Z soundings. and I have to admit, the cap is what I expected in ABR. but for here in the twin cities, that's a much smaller lid than I was thinking. looks like it might get a bit more interesting than I originally thought.

 

but that gust at 57kt at GFK is impressive. the windbag storms are on.

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113 knot delta-v west of Crookston MN, tornado warning

 

attachicon.gif2014_07_22_0157z_MVX_tornado_warning.png

 

Yeah, I saw 120+ kt bins on the right flank of that. The 80+ kt velocities extended out by ~2 miles. I saw a report of a funnel cloud, but it hardly matters if a tornado touched down or not. There had to be close to EF1 winds reaching the surface. Will have to check back and see if a storm survey is completed...

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Insane tornado parameters in place across eastern SD right now... I have never seen such high values before.  I believe that they are capped, but some of the southernmost storms in the MCS are building into this zone with what may be extreme severe weather potential.  There's probably something important I'm missing though.

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post-9379-0-81860800-1405997637_thumb.gi

post-9379-0-23335200-1405997735_thumb.gi

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Insane tornado parameters in place across eastern SD right now... I have never seen such high values before.  I believe that they are capped, but some of the southernmost storms in the MCS are building into this zone with extreme severe weather parameters...

 

They are capped, this is somewhere in the ballpark of what the 6/16 supercell in NE (Pilger) had to work with uncapped, and the results spoke for themselves. 

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Yeah, I saw 120+ kt bins on the right flank of that. The 80+ kt velocities extended out by ~2 miles. I saw a report of a funnel cloud, but it hardly matters if a tornado touched down or not. There had to be close to EF1 winds reaching the surface. Will have to check back and see if a storm survey is completed...

 

There likely were multiple tornadoes in that MCV there, several couplets with what appeared to be TDS'.

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Insane tornado parameters in place across eastern SD right now... I have never seen such high values before.  I believe that they are capped, but some of the southernmost storms in the MCS are building into this zone with what may be extreme severe weather potential.  There's probably something important I'm missing though.

Yeah 19 is a nifty EHI. I think I saw STP values of 11-13 during the April 27 2011 superoutbreak.

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  • 2 months later...

Interesting severe threat this evening into tomorrow across the SW. There are some similarities to 10/6/10, as the closed low migrates slowly eastward and strong flow aloft overspreads potentially moderate buoyancy. Low level shear also appears sufficient for tornadoes if supercells do develop.

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Not impressed with today's setup. 5% tornado risk in a zone where dew-points are generally in the 50s and the best shear is pushing off north. High res models can't agree on secondary initiation after this initial junk, further indicating how messy/marginal the setup is. Yesterday was also a 5% tornado risk day with only one very brief tornado report.

Eastern SD has the strongest shear and proximity to a triple point, but that's where dews are low and instability is expected to be hard to come by. Far eastern Nebraska may have slightly better instability, but somewhat weaker shear and questions about air-mass recovery. Could see a few widely isolated cells in Kansas, but they're displaced from more favorable shear.

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day 2 30% outlook for Kansas City and Topeka.  From the SPC (read the full discussion if you want).

 

---

Day 2 1730z outlook

 

---

FORECAST SOUNDINGS FOR TOPEKA AND EMPORIA KS AT 00Z/THURSDAY SHOW   IMPRESSIVE SHEAR PROFILES WITH 0-6 KM SHEAR OF 55 TO 60 KT.   SUBSTANTIAL VEERING WITH HEIGHT IS FORECAST FROM THE SFC TO ABOUT   800 MB. THIS SHEAR ENVIRONMENT SHOULD SUPPORT SUPERCELL DEVELOPMENT   DURING THE LATE AFTERNOON AND EARLY EVENING. 

--

note: this will not affect the wild card baseball game at Kansas City, which is happening tonight.

 

NAM soundings for 21z tomorrow near Topeka have 2000-3000 J/kg of CAPE with 45kt winds just at 450mb (leading to 0-6km shear of 45-55 knots in some spots). The dew points are going to be about 68 there.

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See, the problem is that the NAM has (I feel like I'm saying this for umpteenth time now) an absolutely horrid record this year. With that said, the Euro appears in decent agreement with it on synoptic features (a bit less CAPE) and the SPC SREF is pretty solid for tomorrow evening in/around the 30% zone. 
 
Upper 60s/70s dewpoints are generally restricted to the TX Gulf Coast currently so I have my questions whether moisture is going to be as high as the NAM suggests.
 
Excellent discussion from TOP regarding tomorrow.
 

WEDNESDAY - WEDNESDAY EVENING:  
THIS PERIOD REMAINS COMPLICATED. THERE IS POTENTIAL FOR SEVERE  
WEATHER ACROSS THE AREA BUT A BIT OF UNCERTAINTY IN HOW SEVERE IT  
WILL BE AND WHERE THE PREFERRED LOCATIONS WILL BE. THE CURRENT  
THINKING, SUBJECT TO CHANGE, IS THIS:  
 
MORNING THUNDERSTORMS, STILL POTENTIALLY EXHIBITING SOME  
BACKBUILDING AND HEAVY RAIN CHARACTERISTICS WILL CONTINUE BUT SHIFT  
EAST OF THE AREA BY AROUND NOON AS WEAK LARGE-SCALE SUBSIDENCE  
OVERSPREADS THE AREA IN THE WAKE OF A SHORT WAVE TROUGH. CLOUDS MAY  
OR MAY NOT BREAK UP A BIT, BUT THE INTERESTING THING IS THAT IT  
SEEMS THAT MODERATE INSTABILITY OF 1500+ J/KG OF CAPE WILL DEVELOP  
EVEN IF CLOUDS DON'T BREAK UP AS THE DRIVING FACTOR FOR INCREASED  
INSTABILITY WILL BE AN INFLUX OF LOW LEVEL MOISTURE (UPPER 60S  
DEWPOINTS). IF BREAKS IN THE CLOUDS ALLOW FOR MORE HEATING, THE  
SEVERE THREAT SEEMS LIKELY TO INCREASE FROM AN ALREADY ELEVATED  
STATE. A SURFACE LOW WILL INTENSIFY OVER CENTRAL KS BY AFTERNOON  
WITH A SYNOPTIC WARM FRONT/INVERTED TROUGH IS LIKELY TO EXTEND  
NORTHEAST ACROSS NORTH CENTRAL KS. A PUNCH OF DRY AIR WILL WRAP  
SOUTH OF THE SURFACE LOW INTO SOUTH CENTRAL KS BY EARLY EVENING  
WHILE AN INTENSE UPPER JET STREAK MOVES INTO THE AREA FOR THE  
EVENING AS WELL. LOW LEVEL WINDS UP TO 800 HPA WILL BACK IN ADVANCE  
OF THE INTENSIFYING SFC LOW BY LATE AFTERNOON, GREATLY INTENSIFYING  
THE LOW LEVEL HELICITY OVER EASTERN KS (AND TO A LESSER EXTENT  
NORTHERN KS) BY EVENING. SOME MODEL GUIDANCE INDICATES THAT OUTFLOW  
BOUNDARIES FROM EARLY DAY CONVECTION MAY PLAY A ROLE IN THE  
AFTERNOON CONVECTIVE EVOLUTION BUT THIS REMAINS UNCERTAIN. IF  
OUTFLOW BOUNDARIES EXIST, THEY WOULD CERTAINLY BECOME A FOCUS FOR  
INITIATION AND ENHANCED VORTICITY. WHEREVER STORMS DEVELOP DURING THE  
LATE AFTERNOON AND EVENING HOURS, THE LIKELY STORM MODE IS DISCRETE  
TO SEMI-DISCRETE SUPERCELLS WITH ALL HAZARDS POSSIBLE. THE TORNADO  
THREAT APPEARS TO BE MAXIMIZED IN EAST CENTRAL KS BETWEEN 6 PM AND  
10 PM WHILE STILL POSSIBLE ON EITHER SIDE OF THAT WINDOW AND TO A  
LESSER EXTENT IN NORTHERN KS. GIVEN THE MAGNITUDE OF LOW LEVEL  
SHEAR/SRH IN CONJUNCTION WITH THE STRONG DEEP SHEAR, A FEW STRONG  
TORNADOES MAY BE POSSIBLE. INHIBITION WILL INCREASE BY LATE EVENING  
WITH A DECREASING POTENTIAL FOR SURFACE BASED STORMS...AND THUS  
DECREASING TORNADO POTENTIAL...ALTHOUGH STILL NON-ZERO THROUGH  
MIDNIGHT. WIND AND HAIL POTENTIAL WILL CONTINUE THROUGH THE PERIOD  
WITH ANY ORGANIZED STORMS, AND LOCALIZED HEAVY RAIN/FLASH FLOODING  
WILL ALSO BE POSSIBLE BUT MORE DEPENDENT UPON TRAINING AS STORMS  
SHOULD BE PROGRESSIVE.

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Not terribly impressed with tomorrow.  Meh low-level wind profiles and so-so mid-level thermodynamics.

 

Have been looking at 00z progs, nothing has the NAM's back aside from the SREF and the SPC WRF brings a line of storms through in the morning over the higher risk areas and then nothing afterwards. Did have some short lived supercells going further south later on though.

 

Speaking broadly, I think it's pretty much a lock for a third straight sub-1000 tornado count year barring the main part of the Fall season going berserk (as in more active than it has essentially ever been).

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 10404895_703472853054180_615283091164057

 

This radar product is an estimate of how much rain has fallen across parts of the area since yesterday afternoon. Though an estimate, the spotty 8 and 9 inch amounts across Lancaster County and the city of Lincoln have been verified with volunteer observer reports. We will have a break today but then another shot of rainfall will arrive overnight into Thursday morning.
 

 

 
 
 
 
 
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The time-frame with the best shear looks to be 00z-06z, so if we do end up with a few tornadoes, I could see some occurring into the night.

 

This was the 12z Topeka sounding. We'll see how much of this low-level jet we lose and if the mid level thermodynamics improve. 

post-533-0-11059300-1412175426_thumb.gif

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Those 70 degree dew-points are being realized in far southeastern Kansas with a group of developing cells headed in that direction. SPC 60% probability per MD of watch issuance. Could be issuing a tornado and or severe thunderstorm watch at any moment.

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SE KS and SW MO looking more and more interesting this evening. What are your thoughts Quincy?

Give it a few hours and I think the environment is very supportive of at least a few tornadoes from SE KS into adjacent W MO. Greatest risk appears to be just NW of I-44 to a bit southeast of I-35. Joplin will be on the fringe.
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The storm mode up north is a big mess. That discrete cell with a nice hook in far southeastern Kansas will eventually interact with a somewhat more favorable air-mass if it holds itself together for a while longer. It's also on a general trajectory toward near Joplin.

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