SWODY1
SPC AC 230548
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1248 AM CDT SAT OCT 23 2010
VALID 231200Z - 241200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM TX TO IA...
...SYNOPSIS...
LONG WAVE TROUGH WILL EASE INTO THE PLAINS SATURDAY WITH A BIMODAL
STRUCTURE EXPECTED TO FOCUS SEVERE ACROSS TX AND OVER THE MID MS
VALLEY REGION. LATEST MODEL GUIDANCE SUGGESTS THE NRN-MOST MID
LEVEL CIRCULATION WILL SHIFT EAST ALONG THE NEB/SD BORDER BY MID
AFTERNOON WHILE THE LOWER LATITUDE FEATURE OVER NRN MEXICO WILL
TRANSLATE INTO CNTRL/S TX. EACH OF THESE FEATURES...WITHIN THE
LONGER WAVE...SHOULD ENHANCE THE CONVECTIVE/SEVERE POTENTIAL
IMMEDIATELY DOWNSTREAM...THOUGH INSTABILITY WILL NOT BE PARTICULARLY
STRONG WITH EITHER SYSTEM.
...CNTRL PLAINS/MID MS VALLEY...
EARLY THIS MORNING...NUMEROUS SHOWERS/THUNDERSTORMS HAVE DEVELOPED
WITHIN WARM ADVECTION ZONE ACROSS ERN KS/MO AND THIS ACTIVITY IS
SPREADING NNEWD INTO ERN NEB/IA. WITH TIME IT APPEARS THE SFC WARM
FRONT WILL RETREAT TO A POSITION FROM CNTRL NEB...NEWD ALONG THE
MN/IA BORDER. BY EARLY AFTERNOON THE STRONGEST BOUNDARY LAYER
HEATING WILL BE FOCUSED IMMEDIATELY AHEAD OF PACIFIC FRONT ACROSS
THE CNTRL PLAINS INTO WRN IA. 00Z NAM IS A BIT MORE AGGRESSIVE WITH
SFC HEATING INTO WRN IA THAN THE GFS AND IF THIS OCCURS
THERMODYNAMIC PROFILES WILL PROVE MORE SUPPORTIVE OF ROBUST UPDRAFTS
AND POSSIBLE SEVERE THAN A WEAKER LAPSE RATE ENVIRONMENT. ALTHOUGH
THE STRONGEST MID LEVEL FLOW WILL BE LOCATED ALONG A BELT FROM TX
INTO IL AT PEAK HEATING...SFC-6KM DEEP LAYER FLOW ON THE ORDER OF
40KT WILL ENCOURAGE STORM ROTATION AND POSSIBLE SUPERCELL
DEVELOPMENT. FORECAST SOUNDINGS SUGGEST READINGS IN THE MID 70S
WILL FREE SFC-BASED PARCELS AND THUNDERSTORMS SHOULD EASILY DEVELOP
AHEAD OF SFC LOW/COLD FRONT. ADDITIONALLY...WARM ADVECTION MAY ALSO
DRIVE WARM FRONTAL CONVECTION WHERE SUPERCELL STRUCTURES ARE ALSO
FEASIBLE. LARGE HAIL MAY ACCOMPANY THE STRONGEST STORMS...ALONG
WITH SEVERE WINDS. GIVEN THE MOIST PROFILES AND STRONG-VEERING WIND
PROFILES A FEW TORNADOES COULD ALSO OCCUR.
...TX...
LARGE SCALE ASCENT IS SPREADING ACROSS THE TRANS PECOS TOWARD THE
EDWARDS PLATEAU EARLY THIS MORNING...AS EVIDENT BY THICKER
CLOUDINESS WITHIN WARM CONVEYOR. THUNDERSTORMS SHOULD EVOLVE ALONG
THE LEADING EDGE OF THIS ASCENT WHEN IT OVERSPREADS THE WRN EDGE OF
MOIST BOUNDARY LAYER...POSSIBLY AS FAR WEST AS SANDERSON-SJT-ABI.
THIS ACTIVITY SHOULD EXPAND QUICKLY INTO AN ELONGATED MCS BEFORE IT
SPREADS INTO PORTIONS OF CNTRL/NRN TX. IT/S NOT ENTIRELY CLEAR HOW
MANY SUPERCELLS WILL EVOLVE AHEAD OF THE LARGER CLUSTER OF
STORMS...BUT DEEP LAYER SHEAR CERTAINLY WOULD SUPPORT
SUPERCELLS...THOUGH STRONGER LOW LEVEL FLOW WILL BE FOCUSED
CONSIDERABLY FARTHER NORTH INTO THE MID MS VALLEY. FOR THIS REASON
TORNADOES MAY STRUGGLE TO DEVELOP WITHIN AN OTHERWISE MOIST/UNSTABLE
AIRMASS AHEAD OF A FAIRLY SIGNIFICANT SHORTWAVE TROUGH. EVEN
SO...LARGE HAIL AND DAMAGING WINDS COULD ACCOMPANY THE STRONGER
EMBEDDED CELLS WITHIN THE LARGER THUNDERSTORM COMPLEX...AND OF
COURSE WITH ANY PRECEDING SUPERCELLS.
..DARROW/STOPPKOTTE.. 10/23/2010
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