Plains tornado threat Mon 5/27-Fri 5/31

[andyhb]

Obviously the NAM has left a lot to be desired with recent events, but the 18z run still has a 160 kt jet max at H25 coming ashore at 63 hrs. I can't recall ever seeing this being progged in late May going into June.

[brettjrob]

Obviously the NAM has left a lot to be desired with recent events, but the 18z run still has a 160 kt jet max at H25 coming ashore at 63 hrs. I can't recall ever seeing this being progged in late May going into June.

 

With that jet streak currently progged to punch out Friday, there are eerie similarities to the 5/19 event from a synoptic standpoint, but shifted 100-200 mi. to the N.

[OUGrad05]

Would be nice to squeeze another good chase day out of this system for central or eastern OK (North of I40).  Right now it's just too far out to nail down the biggest threats, but it seems to me the potential exists from the red river northward to I80 for various portions of this upcoming week.  This may be it for awhile too...

[TropicalAnalystwx13]

I think there's a good chance for a few tornadoes starting tomorrow. The LLJ isn't particularly strong (~40 kts), but CAPE is forecast on the order of 3-4k j/kg across eastern Nebraska into northeastern Kansas and dewpoints predicted to be in the 70s. ESRH tops out at 500-600 m2/s2. There's a lot to be desired with the LCL heights (750-1250 m) but if we get any supercells, they could go crazy.

[andyhb]

I think there's a good chance for a few tornadoes starting tomorrow. The LLJ isn't particularly strong (~40 kts), but CAPE is forecast on the order of 3-4k j/kg across eastern Nebraska into northeastern Kansas and dewpoints predicted to be in the 70s. ESRH tops out at 500-600 m2/s2. There's a lot to be desired with the LCL heights (750-1250 m) but if we get any supercells, they could go crazy.

 

A 40 kt LLJ with that amount of instability is plenty, and the LCL heights are not particularly high either, certainly manageable.

[thewxmann]

NAM forecast sounding tmrw, for areas just west of Salina: 

http://www.twisterdata.com/index.php?sounding.lat=39.0618&sounding.lon=-98.0420&prog=forecast&model=NAM&grid=221&model_yyyy=2013&model_mm=05&model_dd=27&model_init_hh=00&fhour=24&parameter=TMPF&level=2&unit=M_ABOVE_GROUND&maximize=n&mode=singlemap&sounding=n&output=image&view=large&archive=false&sounding=y&sndclick=y

[brettjrob]

I think there's a good chance for a few tornadoes starting tomorrow. The LLJ isn't particularly strong (~40 kts), but CAPE is forecast on the order of 3-4k j/kg across eastern Nebraska into northeastern Kansas and dewpoints predicted to be in the 70s. ESRH tops out at 500-600 m2/s2. There's a lot to be desired with the LCL heights (750-1250 m) but if we get any supercells, they could go crazy.

 

LCL heights of 750-1250 m are almost the textbook range for Plains tornadoes, actually. If that's what verifies, it certainly won't be the limiting factor. To me, the main limiting factor will be the lack of low-level shear over the open warm sector, away from the baroclinic zone/boundary in N KS. However, the dryline/boundary intersection appears the most likely area for initiation, so I agree that a few tornadoes are quite possible, if not likely.

[andyhb]

Jumping ahead to Thursday, I saw some ridiculous wind fields looking at soundings on the 18z GFS in OK and KS eastward into MO. If we do get a replenishment of steep mid level lapse rates like the D4-8 suggested this morning, there could be two or more main areas of potential. This was also suggested by the CIPS which basically had a wide assortment of event locations.

 

That said, the 00z run tonight looks a bit more veered out in the low levels compared to last night's run, partly due to the s/w that rotates around the ULL moving a lot faster on this run (and overall the trough looks more progressive).

[brettjrob]

FWIW, the 4 km NAM tonight again suggests a long-lived supercell with several hours of maxed-out UH in north-central KS during the early evening hours.

[jojo762]

Jumping ahead to Thursday, I saw some ridiculous wind fields looking at soundings on the 18z GFS in OK and KS eastward into MO. If we do get a replenishment of steep mid level lapse rates like the D4-8 suggested this morning, there could be two or more main areas of potential. This was also suggested by the CIPS which basically had a wide assortment of event locations.

Pretty sweet hodographs too... Nice long curvature.

[Chicago Storm]

Unfortunately work will keep me out of the Plains until mid-week.

 

Hopefully Thur/Fri produce quite well.

[Chinook]

NAM forecast sounding tmrw, for areas just west of Salina: 

http://www.twisterdata.com/index.php?sounding.lat=39.0618&sounding.lon=-98.0420&prog=forecast&model=NAM&grid=221&model_yyyy=2013&model_mm=05&model_dd=27&model_init_hh=00&fhour=24&parameter=TMPF&level=2&unit=M_ABOVE_GROUND&maximize=n&mode=singlemap&sounding=n&output=image&view=large&archive=false&sounding=y&sndclick=y

That's pretty awesome stuff.

[Ed Lizard]

That's pretty awesome stuff.

EHI of almost 9 per NIU sounding generator, useful for us amateurs that want numbers.

[andyhb]

NSSL WRF has a powerful supercell with maxed out UH moving across that sweet spot around the I-70 corridor in KS tomorrow.

[tornadotony]

SPC WRF nails KS tomorrow evening and has a major supercell along or just N of I-40 in wrn/cntl OK tomorrow.  GFS wind profile would support significant tornado activity.

 

[brettjrob]

Goodness. Only other time I *personally* recall seeing that UH signature was the run the night before 5/19 (Edmond and Shawnee), and it almost nailed that.

 

[andyhb]

This setup tomorrow is a bit reminiscent of the Hallam event in 2004 albeit shifted a bit further south with the same kind of broad, low amplitude wave passing through a highly unstable warm sector, and a sfc low in a rather similar position and orientation. It is the number four analog with CIPS tonight.

[jcwxguy]

it has nice storms moving right over head around 0300z (right after i get off work )

[brettjrob]

This setup tomorrow is a bit reminiscent of the Hallam event in 2004 albeit shifted a bit further south.

 

I'd have to pull up some synoptic charts for that event to compare in detail, but one way in which that's true is the apparent potential for a western and eastern mode. The western "wrap-around" mode fires earlier on the hi-res models which have it, while the eastern mode right at the DL bulge is closer to sunset. In the case of 5/22/04, the earlier activity was actually much more photogenic and less HP (albeit not as incredibly violent, of course), but that may well have been idiosyncratic to that particular setup.

 

it has nice storms moving right over head around 0300z

 

That might be an understatement, if you're referring to the NSSL WRF. Hopefully if its general idea verifies, SLN and MPR are out of the path.

[jcwxguy]

 

 

That might be an understatement, if you're referring to the NSSL WRF. Hopefully if its general idea verifies, SLN and MPR are out of the path.

 

 

 

looks good to me lol

[jcwxguy]

new day 2

 

[andyhb]

Speaking of the I-70 corridor in KS...the wave ejecting tomorrow looks a tad similar.

[jcwxguy]

[andyhb]

Discussion:

 

DAY 1 CONVECTIVE OUTLOOK     NWS STORM PREDICTION CENTER NORMAN OK   0100 AM CDT MON MAY 27 2013   VALID 271200Z - 281200Z   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF THE HIGH PLAINS   TO THE LOWER/MIDDLE MO VALLEY AND MIDWEST...   ...CENTRAL PLAINS/MO VALLEY TO MIDWEST/MIDDLE MS VALLEY...   SCATTERED LINEAR-TYPE CLUSTERS AND PERHAPS EVEN A LINGERING   SEMI-SUSTAINED/ORGANIZED MCS WILL LIKELY BE ONGOING AT THE BEGINNING   OF THE PERIOD ACROSS THE MIDDLE/LOWER MO VALLEY TO THE MIDDLE MS   VALLEY VICINITY. ASSOCIATED CONVECTIVE OUTFLOW ACROSS PARTS OF   NEB/KS INTO IA/NORTHERN MO WILL LIKELY BE A KEY FACTOR FOR   EFFECTIVELY DEFINING/REINFORCING A ROUGHLY WEST-EAST BAROCLINIC ZONE   LATER TODAY.    ASIDE FROM WHAT MAY BE AN EPISODIC WIND/HAIL THREAT ACROSS PARTS OF   THE MIDWEST/MIDDLE MS VALLEY/LOWER OH VALLEY DURING THE DAY...A MORE   CONSEQUENTIAL SEVERE RISK IS EXPECTED TO EVOLVE ACROSS THE CENTRAL   PLAINS/MO VALLEY FROM MID/LATE AFTERNOON INTO THIS EVENING. THIS   SCENARIO WILL BE AIDED A SUBTLY CYCLONIC BELT OF MID-HIGH LEVEL   WESTERLIES AND A POTENTIAL APPROACHING/EMBEDDED SHORTWAVE IMPULSE OR   TWO.    THE MOST PROBABLE AREA FOR INITIAL SURFACE BASED STORM DEVELOPMENT   APPEARS TO BE ALONG AN OUTFLOW-AIDED/EFFECTIVE BOUNDARY INDUCED   TRIPLE POINT NEAR/EAST OF A WEST-CENTRAL/NORTH-CENTRAL KS SURFACE   LOW. THIS INCLUDES PARTS OF CENTRAL/NORTHERN KS INTO SOUTHERN NEB.   WITH MIDDLE/UPPER 60S F AND PERHAPS EVEN SOME NEAR 70 F SURFACE   DEWPOINTS BENEATH A VERY STEEP ELEVATED MIXED PLUME /MID-LEVEL RATES   LIKELY EXCEEDING 8 DEG PER KM/...THE BOUNDARY LAYER WILL LIKELY   BECOME STRONGLY UNSTABLE BY AFTERNOON...WITH MLCAPES LIKELY TO REACH   3000-4000 J/KG ESPECIALLY ACROSS CENTRAL KS AND POTENTIALLY INTO FAR   SOUTHERN NEB/WESTERN MO. IT SHOULD ALSO BE NOTED THAT A SOMEWHAT   SEPARATE AREA FOR ADDITIONAL SEVERE TSTM DEVELOPMENT...INCLUDING A   COUPLE OF SUPERCELLS...MAY OCCUR THIS AFTERNOON/EARLY EVENING ACROSS   WESTERN KS/FAR SOUTHWEST NEB NEAR THE ANGLING BAROCLINIC ZONE WITHIN   THE NORTHWEST QUADRANT OF THE WESTERN KS SURFACE LOW.   BASED ON SOME EXPECTED TROUGH AMPLIFICATION AND UPSTREAM EVENING   SOUNDING OBSERVATIONS OVER THE WESTERN CONUS...A BIT STRONG STRONGER   /BY 5-10 KT/ WEST-SOUTHWESTERLY MID-HIGH LEVEL FLOW SEEMS PROBABLE   ACROSS THE CENTRAL PLAINS/MO VALLEY WARM SECTOR.   ACCORDINGLY...EFFECTIVE BULK SHEAR OF AT LEAST 35-45 KT WILL LIKELY   EXIST ACROSS THE WARM SECTOR...WITH EVEN STRONGER VALUES ALONG THE   WSW-ENE EFFECTIVE BOUNDARY. THIS WILL SUPPORT THE POSSIBILITY OF   SOME INTENSE SUPERCELLS WITH VERY LARGE HAIL...ALONG WITH THE   POSSIBILITY OF TORNADOES...ONE OR TWO POSSIBLY STRONG GIVEN AN   EXPECTED EARLY EVENING LOW LEVEL JET INCREASE AND ASSOCIATED   LENGTHENING/CURVING LOW-LEVEL HODOGRAPHS.    AIDED BY THIS STRENGTHENING LOW-LEVEL JET...STORMS SHOULD ULTIMATELY   GROW UPSCALE AND PROPAGATE EAST OR PERHAPS A BIT SOUTHEASTWARD   TOWARD/ACROSS PARTS OF EASTERN KS/SOUTHERN NEB INTO MO/SOUTHERN IA.   GIVEN SUCH...DAMAGING WIND POTENTIAL WOULD INCREASE ASIDE FROM   CONTINUED BOUTS OF SEVERE HAIL THROUGH THE LATE EVENING/OVERNIGHT   HOURS.

[andyhb]

D3:

 

DAY 3 CONVECTIVE OUTLOOK     NWS STORM PREDICTION CENTER NORMAN OK   0228 AM CDT MON MAY 27 2013   VALID 291200Z - 301200Z   ...THERE IS A SLGT RISK OF SVR TSTMS OVER A LARGE PORTION OF THE   PLAINS STATES AND A PART OF THE UPPER MS RIVER VALLEY...   ...SYNOPSIS...   THE SRN EXTENSION OF A POTENT LARGE SCALE UPPER TROUGH WILL PIVOT   FROM THE CNTRL-SRN ROCKIES INTO THE CNTRL-SRN PLAINS.  A STOUT UPPER   RIDGE WILL AMPLIFY FROM THE CNTRL APPALACHIANS TO THE UPPER GREAT   LAKES DOWNSTREAM OF THE LARGE SCALE TROUGH TO THE W.  IN THE LOW   LEVELS...A DUAL SURFACE LOW STRUCTURE WILL SEEMINGLY EVOLVE WITH   AREAS OF LOW PRESSURE OVER THE WRN DAKOTAS AND FARTHER S OVER ERN   CO.  A WARM FRONT IS FORECAST TO ADVANCE NWD OVER THE UPPER MIDWEST   EWD INTO PARTS OF THE NERN U.S.   ...PLAINS AND UPPER MS RIVER VALLEY...   MEDIUM RANGE MODELS SHOW THE GRADUAL BACKING OF MID-HIGH LEVEL FLOW   OVER MUCH OF THE PLAINS DURING THE DAY 3 PERIOD.  DEEP LAYER SHEAR   VECTORS ARE LARGEST AND MOST ORTHOGONAL RELATIVE TO THE DRYLINE OVER   PARTS OF THE SRN PLAINS TOWARDS THE BASE OF THE UPPER TROUGH AXIS.    AS A RESULT...THE TENDENCY FOR INITIATING BOTH DISCRETE MODES AND   SUSTAINING ROBUST LONGER-LIVED UPDRAFTS APPEARS MOST PROBABLE FROM   PARTS OF WRN OK/NWRN TX ALONG THE DRYLINE.  MID-UPPER 60S DEWPOINTS   AND STRONG HEATING WILL SUBSTANTIALLY DESTABILIZE THE AIRMASS E OF   THE DRYLINE.  ISOLD LARGE TO VERY LARGE HAIL --ESPECIALLY EARLIER ON   DURING THE THUNDERSTORM LIFE CYCLE-- SEVERE STRAIGHT-LINE   WINDS...AND A FEW TORNADOES WOULD BE POSSIBLE.   FARTHER N...AN EXPANDING WARM/MOIST SECTOR OVER THE NRN PLAINS/UPPER   MS RIVER VALLEY WILL BECOME MORE FAVORABLE FOR SHOWERS/STORMS AS THE   INFLUENCE OF STRONGLY DIFFLUENT UPPER FLOW OVERSPREADS THESE   REGIONS.  A BROAD CORRIDOR OF STRONG SLY H85 FLOW WILL ACT TO   MAINTAIN A MOIST FEED FROM THE SOUTH ACTING TO DESTABILIZE THIS   REGION.  BANDS OF STRONG TO SEVERE STORMS WILL PROBABLY INCREASE IN   NUMBER AND INTENSITY DURING THE DAY.  BOUNDARY LAYER STABILIZATION   PROCESSES SUCH AS CONVECTIVE OVERTURNING AND LOSS OF DAYTIME HEATING   SHOULD ACT TO LESSEN THE SEVERE THREAT DURING THE TRANSITION FROM   THE EVENING INTO THE LATE NIGHT HOURS.   ...NY/PA/NJ...   ISOLD-SCTD STORMS MAY DEVELOP DURING PEAK HEATING IN ASSOCIATION   WITH A WEAK DISTURBANCE CRESTING THE NRN PERIPHERY OF THE MID LEVEL   ANTICYCLONE CENTERED FARTHER S OVER THE CAROLINAS.  A LARGELY   UNIDIRECTIONAL WIND PROFILE WOULD FAVOR EWD MOVING MULTICELLS   PERHAPS CAPABLE OF ISOLD DMGG WIND AND SMALL HAIL BEFORE WEAKENING   DURING THE EVENING.   ..SMITH.. 05/27/2013

[andyhb]

D4-8:

 

DAY 4-8 CONVECTIVE OUTLOOK     NWS STORM PREDICTION CENTER NORMAN OK   0351 AM CDT MON MAY 27 2013   VALID 301200Z - 041200Z   ...DISCUSSION...   THE UPPER AIR PATTERN DURING THE EARLY PART OF THE EXTENDED PERIOD   WILL FEATURE AN EXPANSIVE MID LEVEL TROUGH/LOW CENTERED OVER THE NRN   PLAINS.  MODELS GENERALLY AGREE IN SHOWING THIS FEATURE GRADUALLY   WEAKENING LATE IN THE WORK WEEK INTO NEXT WEEKEND BUT THE MODELS   MAINTAIN A STRONG BELT OF WSWLY FLOW OVER THE CNTRL PLAINS NEWD INTO   THE MIDWEST/GREAT LAKES.  THE RISK FOR SEVERE STORMS WILL GREATLY   HINGE ON THE DETAILS WITH REGARD TO THE MID LEVEL TROUGH EVOLUTION   DURING THE THURSDAY-FRIDAY /DAY 4-5/ PERIOD.  WITH THAT   STATED...CONFIDENCE IS HIGH ENOUGH TO INCLUDE A 30 PERCENT SEVERE   PROBABILITY AREA OVER PARTS OF KS-OK ON THURSDAY /DAY 4/.  A RENEWED   ORGANIZED SEVERE THREAT IS POSSIBLE OVER THE SAME GENERAL AREA ON   FRIDAY /DAY 5/ BUT CONFIDENCE IN THIS SCENARIO IS SLIGHTLY LOWER   --PRECLUDING A HIGHLIGHTED AREA AT THIS TIME.  FARTHER NE...A   SUBSTANTIAL SEVERE THREAT MAY EXIST INTO PARTS OF THE MIDWEST BOTH   THURSDAY AND FRIDAY /DAY 4-5/.  BY SATURDAY /DAY 6/...SOME SEVERE   THREAT MAY DEVELOP OVER THE GREAT LAKES AHEAD OF THE WEAKENING   TROUGH...BUT MAGNITUDE OF THREAT AND PREDICTABILITY CONCERNS   PRECLUDE AN AREA HIGHLIGHT.   ..SMITH.. 05/27/2013

[Ian]

Interesting the shift on D3 from yesterday's d4.

[baroclinic_instability]

Not a surprise to see a small Mod risk given the potential.

 

SPC AC 271247

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0747 AM CDT MON MAY 27 2013

VALID 271300Z - 281200Z

...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF KS AND NEB...

...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK
AREA...FROM THE NRN HIGH PLNS THROUGH THE CNTRL PLNS TO THE MID MS
VLY AND PARTS OF THE SRN PLNS...

...SYNOPSIS...
SLOWLY PROGRESSIVE...DIFFLUENT...LARGE-SCALE TROUGH WILL PREVAIL
OVER THE WEST THIS PERIOD...WHILE A SERIES OF LESSER...FASTER-MOVING
DISTURBANCES FLATTEN RIDGE OVER ERN PORTIONS OF THE PLNS AND THE MS
VLY. ONE SUCH IMPULSE NOW OVER ID WILL CONTINUE NE INTO SE MT THIS
EVE...AND INTO ND EARLY TUE. IN A BRANCH OF SOMEWHAT ENHANCED SWLY
FLOW FARTHER S...SEVERAL WEAK IMPULSES NOW OVER THE FOUR CORNERS
REGION AND CO ARE POISED TO TRACK NE INTO THE CNTRL PLNS.

AT THE SFC...LOW NOW OVER WRN KS WILL REMAIN NEARLY STNRY WHILE
ELONGATING NEWD IN RESPONSE TO PASSING SRN STREAM DISTURBANCES.
BROAD CURRENT OF MOIST SSWLY LOW-LVL FLOW E OF THE LOW WILL ONCE
AGAIN SERVE TO SUPPORT SEVERAL ROUNDS OF DIURNALLY-ENHANCED TSTM
DEVELOPMENT. THE MOST CONCENTRATED ACTIVITY IS EXPECTED NEAR
WARM/STNRY FRONT EXTENDING FROM SRN NEB ESE INTO THE MID MS
VLY...AND ALONG OUTFLOW BOUNDARIES LEFT BY OVERNIGHT STORMS IN THE
SAME GENERAL REGION.

...CNTRL PLNS/LWR MO VLY ESE TO MID MS VLY TODAY/TNGT...
WNW-ESE ORIENTED FRONT...ENHANCED BY CONVECTIVE OUTFLOW FROM
OVERNIGHT MCS NOW IN NE KS/NW MO...LIKELY WILL BE THE MAIN FOCUS FOR
STRONG TO SVR STORMS THIS PERIOD. ELEVATED STORMS ATOP THE MCS COLD
POOL IN ERN NEB...AND LEADING-LINE CONVECTION IN KS-MO...MAY POSE AN
ISOLD SVR HAIL/WIND THREAT THROUGH MID MORNING. BUT A MORE
APPRECIABLE SVR THREAT MAY EVOLVE THIS AFTN AND EVE AS SFC HEATING
AND APPROACH OF SRN STREAM DISTURBANCES FURTHER DESTABILIZE REGION.

ATTM IT APPEARS THAT THE MOST LIKELY AREA FOR AFTN/EVE SVR STORM
DEVELOPMENT WILL BE NEAR INTERSECTION OF OUTFLOW BOUNDARY/FRONT WITH
ELONGATING KS SFC LOW. WIND PROFILES IN THIS REGION SHOULD BE
FAVORABLE FOR SUPERCELLS...WITH 30-40 SSWLY 850 MB WINDS VEERING TO
40 KT WSWLY FLOW AT 500 MB. COUPLED WITH MODEST BUT MOIST/BACKED
NEAR-SFC WINDS INVOF FRONT/OUTFLOW BOUNDARY...SETUP COULD YIELD A
CLUSTER OF SUPERCELLS WITH A SIZABLE RISK FOR TORNADOES /ONE OR TWO
POSSIBLY STRONG/ IN N CNTRL KS AND PERHAPS ADJACENT SRN NEB...IN
ADDITION TO LARGE HAIL/DMGG WIND. A FEW SVR STORMS ALSO COULD FORM
FARTHER WNW OVER THE NEB PANHANDLE...NE CO...AND NW KS...WHERE MOIST
ELY FLOW ON N SIDE OF KS LOW IMPINGES ON INVERTED SFC TROUGH.

CONTINUED NE MOTION OF SRN STREAM UPR DISTURBANCES...AND DIURNAL
INFLUENCES...SHOULD FURTHER STRENGTHEN 850 MB SSW FLOW ACROSS THE
ERN HALF OF KS AND MUCH OF MO TNGT. IN ADDITION TO POSSIBLY
MAINTAINING A RISK FOR TORNADOES INTO MID-EVE...EXPECT THAT
STRENGTHENED LOW-LVL FLOW ALSO WILL PROMOTE FAIRLY WIDESPREAD MCS
DEVELOPMENT FROM PARTS OF NEB/SRN SD ESE INTO IA AND NRN MO. THESE
SYSTEMS MAY BECOME FAIRLY WELL-ORGANIZED...WITH ASSOCIATED BOWING
SEGMENTS POSING A RISK FOR HIGH WIND...HAIL...AND HEAVY RAIN THROUGH
EARLY TUE.

...NRN HIGH PLNS THIS AFTN/EVE...
SFC HEATING...WEAK UPSLOPE FLOW...AND ASCENT AHEAD OF ID UPR IMPULSE
SHOULD PROMOTE ANOTHER ROUND OF STRONG TO SVR TSTMS ALONG AN ARC
FROM ERN MT SSE INTO NE WY AND THE WRN DAKOTAS LATER TODAY INTO
TNGT. WHILE THE WIND/THERMODYNAMIC ENVIRONMENT DOES NOT APPEAR IDEAL
FOR A STRONGLY-ORGANIZED SVR WEATHER EVENT...SUFFICIENT SHEAR AND
BUOYANCY WILL EXIST FOR A FEW SUSTAINED STORMS AND SUPERCELLS
CAPABLE OF HAIL AND HIGH WIND. THIS ACTIVITY SHOULD FOCUS ALONG
INVERTED TROUGH EXTENDING NNW FROM KS SFC LOW...AND COULD EVOLVE
INTO A BAND OR CLUSTER POSING A SOMEWHAT GREATER DMGG WIND THREAT BY
EARLY EVE.

...SRN HIGH PLNS THIS AFTN/EVE...
ISOLD TO WDLY SCTD TSTMS SHOULD FORM ALONG SRN PLNS DRY LINE LATE
THIS AFTN AND EVE...WHERE UPR DIFFLUENCE AND WNWLY DEEP SHEAR WILL
BE SOMEWHAT ENHANCED /30-35 KTS/ ALONG AND JUST S OF SRN BRANCH JET.
COMBINATION OF FAIRLY RICH MOISTURE /PW AOA 1.25 INCHES WITH SFC DEW
POINTS IN THE MID 60S F/...CONTINUING PRESENCE OF AN EML...AND
STRONG SFC HEATING SHOULD YIELD MODERATE TO STRONG
INSTABILITY...WITH SBCAPE AOA 2000 J/KG. THIS SETUP MAY YIELD
SUPERCELLS CAPABLE OF LARGE HAIL/LOCALLY DMGG WIND AND POSSIBLY A
TORNADO OR TWO....ESPECIALLY IN THE ERN TX PANHANDLE...NW TX...AND
WRN OK.

..CORFIDI/BOTHWELL.. 05/27/2013

[baroclinic_instability]

12z NAM rolling in has some of the sickest looking hodographs I have seen in the plains in a long time. These quasi upslope events are always tricky events to forecast since initiation is not always associated with a well defined boundary, but today has serious potential for a long lived supercell event. A chasers dream today if storms don't cluster early. Even if they do, the nature of these events can lend themselves to multiple rounds as clusters form farther E with repeat rounds of DMC farther W. 

[OUGrad05]

12z NAM rolling in has some of the sickest looking hodographs I have seen in the plains in a long time. These quasi upslope events are always tricky events to forecast since initiation is not always associated with a well defined boundary, but today has serious potential for a long lived supercell event. A chasers dream today if storms don't cluster early. Even if they do, the nature of these events can lend themselves to multiple rounds as clusters form farther E with repeat rounds of DMC farther W. 

What do you think their primary concern is regarding initiation/convection?  The info I'm looking at seems to warrant a 15% hatched area, as you stated those hodo's are really impressive.  Always plenty of time left today for an upgrade...but I'd definitely be worried about the potential for long track tornadoes today.