SPC AC 220559
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1259 AM CDT THU APR 22 2010
VALID 221200Z - 231200Z
...THERE IS A SLGT RISK OF SVR TSTMS CENTRAL/SRN HIGH PLAINS TO
PORTIONS CENTRAL TX...CENTRAL OK AND SRN KS....
...SYNOPSIS...
SPLIT-FLOW PATTERN ALOFT WILL DOMINATE PATTERN ACROSS MUCH OF MAIN
BODY OF NORTH AMERICA THROUGH PERIOD...FEATURING LARGE CYCLONIC GYRE
NOW CENTERED OVER SRN NV. SEVERAL VORTICITY LOBES AND ACCOMPANYING
SHORTWAVE TROUGHS WILL CONTINUE TO ORBIT THIS CIRCULATION AS IT
MOVES SLOWLY EWD THROUGH PERIOD...ITS CENTROID CROSSING NRN AZ
DURING LATE AFTERNOON/EARLY EVENING TIME FRAME. ONE OF THOSE
SHORTWAVES...NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER SRN CA
COASTAL WATERS...IS FCST TO PIVOT THROUGH CYCLONICALLY CURVING PATH
ACROSS NERN MEX BY 23/00Z THEN ACROSS NM TO CENTRAL HIGH PLAINS BY
END OF PERIOD. THIS FEATURE MAY EVOLVE INTO SEPARATE/SECONDARY
CYCLONE CENTER OVER ERN CO BY END OF PERIOD. MEANWHILE...SOMEWHAT
WEAKER/INITIALLY EJECTING PERTURBATION -- EVIDENT ATTM INVOF NERN
BAJA -- SHOULD EJECT NEWD ACROSS MUCH OF NM BY 22/18Z THEN OVER ERN
CO DURING DAY.
AT SFC...CYCLONE SHOULD REMAIN OVER ERN CO THROUGH MUCH OF
DAY...WITH WARM FRONT ESEWD ACROSS WRN/SRN KS. BY MID-LATE
AFTERNOON..EXPECT DRYLINE OVER SWRN KS TO E-CENTRAL TX PANHANDLE TO
NRN COAHUILA. LOW-LEVEL COLD FRONT -- NEARLY COLLOCATED WITH PLUME
OF DEEP LIFT PRECEDING MID-UPPER CYCLONE -- WILL CROSS MOST IF NOT
ALL OF NM BY 23/00Z THEN OVER PANHANDLES INTO WRN OK AND W-CENTRAL
TX OVERNIGHT.
...CENTRAL/SRN PLAINS...
SVR TSTMS ARE EXPECTED FROM W TX TO WRN KS AND NERN CO...WITH AT
THESE THREE PRIMARY EPISODES POSSIBLE...
1. ONGOING AT 22/12Z THROUGH LATE MORNING...AS EWD EXTENSION OF
EWD-SHIFTING REGIME OF DEEP-LAYER ASCENT AND INCREASING CONVECTION
ALREADY EVIDENT ATTM OVER PORTIONS NM.
2. DEVELOPMENT INVOF DRYLINE BEHIND EARLY-PERIOD ACTIVITY...WHICH
ITSELF MAY BE SPORADIC PROCESS THROUGHOUT AFTERNOON INTO EVENING
GIVEN EXPECTED WEAKNESS OF CINH IN MUCH OF THIS CORRIDOR.
3. BAND OF SCATTERED-NUMEROUS TSTMS PROBABLE DURING LATTER HALF OF
PERIOD...MOVING EWD/NEWD ACROSS PORTIONS WRN/CENTRAL TX AND
WRN/CENTRAL OK.
IN ADDITION...BACKED LOW-LEVEL WINDS AND UPSLOPE FLOW COMPONENT WILL
AID CONVECTIVE POTENTIAL...INCLUDING THREAT FOR SUPERCELLS/TORNADOES
OVER NERN CO GIVEN SUFFICIENT DIURNAL DESTABILIZATION BEHIND EARLY
ACTIVITY. FARTHER SSE...WITHIN BROAD CATEGORICAL OUTLOOK
PLUME...ONE OR TWO RATHER FOCUSED/MESOBETA-SCALE AREAS FOR
SUPERCELLS...SIGNIFICANT HAIL AND TORNADOES SHOULD DEVELOP AS WELL.
HOWEVER...CONVECTIVELY MESSY NATURE OF THIS SITUATION...ESPECIALLY
EARLY IN PERIOD...CASTS CONSIDERABLE UNCERTAINTY ATTM ON WHERE THOSE
FOCI WILL SET UP. THEREFORE...IT STILL IS TOO SOON TO ASSIGN
PROBABILITIES AOA CATEGORICAL MDT-RISK CRITERIA.
MODEL FCST SOUNDINGS AWAY FROM EXCESSIVELY STABILIZING CONVECTIVE
INFLUENCES REASONABLY SHOW STEEP LOW-MIDLEVEL LAPSE
RATES...VERTICALLY JUXTAPOSED WITH INCREASING SFC DEW POINTS AND
BOUNDARY LAYER MOISTURE CONTENT. WHERE THIS AIR MASS CAN BE HEATED
ON A SUSTAINED/ROBUST BASIS BEHIND EARLY-PERIOD
CONVECTION...POTENTIAL EXISTS FOR MLCAPE 1500-2000 J/KG...SUPPORTED
BY 50S DEW POINTS OVER WRN KS/ERN CO AND 60S FROM WRN OK SWD.
EXPECT WHAT MAY BE TERMED A TOP-HEAVY BUOYANT PROFILE...WITH LARGE
PERCENTAGE OF CAPE ABOVE 500 MB. VERTICAL WIND PROFILES WILL
SUPPORT SUPERCELLS...WITH BACKED SFC WINDS UNDER MORE MERIDIONAL
FLOW OVER WRN CO/WRN KS...AND MORE CLASSICAL VEERING WITH HEIGHT
ACROSS PANHANDLES SWD OVER W-CENTRAL TX. EFFECTIVE SHEAR 45-55 KT
AND 0-1 KM SRH 100-200 J/KG SHOULD BE COMMON.
THREAT SHOULD TRANSITION TO MIXTURE OF WIND/HAIL AS MORE LINEAR MODE
BEGINS TO DOMINATE THROUGH NIGHTTIME HOURS...AND PRIMARY ZONE OF
ACTIVITY SHIFTS EWD ACROSS CENTRAL/SRN KS...WRN/CENTRAL OK AND
WRN/NRN TX.
..EDWARDS/GARNER.. 04/22/2010
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NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
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