May 10, 2011 1730 UTC Day 2 Convective Outlook
Updated: Tue May 10 17:33:02 UTC 2011
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20110510 1730 UTC Day 2 Outlook Graphic
Probabilistic Graphic
20110510 1730 UTC Day Probabilitic Graphic
Probability of severe weather within 25 miles of a point.
Hatched Area: 10% or greater probability of significant severe within 25 miles of a point.
   SPC AC 101730
   
   DAY 2 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1230 PM CDT TUE MAY 10 2011
   
   VALID 111200Z - 121200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS PORTIONS KS/OK...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ELSEWHERE ACROSS PORTIONS
   CENTRAL/SRN PLAINS FROM NEB TO S TX...
   
   ...SYNOPSIS...
   MID-UPPER LEVEL SYNOPTIC PATTERN WILL BE DOMINATED BY WRN CONUS
   TROUGHING...AND HIGH-AMPLITUDE RIDGING FROM CENTRAL GULF TO UPPER
   GREAT LAKES.  AS HEIGHTS FALL OVER PAC NW AHEAD OF CYCLONE NOW OVER
   GULF OF AK...DOWNSTREAM TROUGH/RIDGE PATTERN GENERALLY WILL MOVE
   SLOWLY EWD THROUGH PERIOD.  LEADING WRN SHORTWAVE TROUGH -- NOW
   ACCOMPANIED BY SMALL/CLOSED 500-MB CYCLONE OVER SERN MT -- IS FCST
   TO EJECT SLOWLY NEWD TO SRN MB THROUGH REMAINDER DAY-1 PERIOD. 
   MEANWHILE...STG SHORTWAVE TROUGH -- NOW EVIDENT IN MOISTURE CHANNEL
   IMAGERY OVER LOWER CO RIVER REGION -- IS FCST TO SWIVEL NEWD ACROSS
   AZ DAY-1.  THIS PERTURBATION SHOULD EVOLVE INTO CLOSED 500-MB
   CYCLONE OVER SAN JUAN MOUNTAINS BY 11/12Z...THEN MOVE ENEWD ACROSS
   CENTRAL HIGH PLAINS BY END OF PERIOD.  WEAK TROUGH OF
   PAC/SUBTROPICAL ORIGIN SHOULD MOVE NEWD ACROSS CENTRAL TX EARLY IN
   PERIOD...PRIOR TO 21Z.
   
   AT SFC...CYCLONE ASSOCIATED WITH INITIAL/NRN SHORTWAVE TROUGH IS
   ELONGATED ACROSS NRN SD ATTM...BUT SHOULD CONSOLIDATE THROUGH
   REMAINDER DAY-1 AND MOVE NEWD ACROSS SRN MB.  BY 11/12Z...EXPECT
   TRAILING OCCLUDED FRONT SEWD TO TRIPLE-POINT LOW OVER MSP/LSE
   REGION.  DIFFUSE WARM FRONTAL ZONE -- ADJUSTED ON MESOSCALE BY
   CONVECTIVE OUTFLOWS -- WILL EXTEND GENERALLY FROM TRIPLE-POINT AREA
   ESEWD ACROSS OH...BENDING SWWD THEN SEWD OVER WRN/SRN APPALACHIANS
   THEN SEWD ACROSS GA.  WAVE LOW MAY DEVELOP ALONG WARM FRONT OVER OR
   JUST OFFSHORE GA COAST EARLY IN PERIOD IF MCV DEVELOPS FROM DAY-1
   CONVECTION FARTHER NW.
   
   QUASISTATIONARY FRONT WILL EXTEND FROM NRN TRIPLE POINT SWWD ACROSS
   NRN/WRN IA...SERN/S-CENTRAL NEB...TO STRENGTHENING CYCLONE OVER SWRN
   KS.  THIS CYCLONE SHOULD DEEPEN FURTHER AND DRIFT NEWD THROUGH
   DAY...REACHING W-CENTRAL KS BY 12/00Z...WITH DRYLINE ARCHING SEWD
   OVER WRN/S-CENTRAL KS...SWD ACROSS W-CENTRAL OK AND WRN PORTIONS
   N-CENTRAL TX TO WRN HILL COUNTRY AND EDWARDS PLATEAU REGIONS OF TX.
   
   ...CENTRAL/SRN PLAINS...
   MOST SIGNIFICANT/CONCENTRATED SVR POTENTIAL STILL APPEARS TO BE JUST
   AHEAD OF DRYLINE FROM NEAR SFC LOW SEWD AND SWD OVER OK AND PORTIONS
   CENTRAL TX...THOUGH SOME CAVEATS COMPLICATE POTENTIAL IN EACH OF
   THREE MAIN AREAS OUTLINED BELOW.  IN GENERAL...BROAD MOIST
   SECTOR...CHARACTERIZED BY MID-UPPER 60S AND LOW-70S SFC DEW POINTS
   AND INTENSIFYING BULK SHEAR...WILL FAVOR RATHER BROAD SVR TSTM
   POTENTIAL LIKELY ASSOCIATED WITH 3 PHASES...EACH WITH SOME SPATIAL
   OVERLAP...
   
   1. EARLIEST DEVELOPMENT MAY OCCUR FROM MID-LATE MORNING THROUGH
   EARLY AFTERNOON IN ASSOCIATION WITH LEADING/SRN-STREAM PERTURBATION
   OVER PORTIONS CENTRAL/SRN TX...AHEAD OF DRYLINE IN ZONE OF WEAKENED
   CINH.  ENVIRONMENT WILL BE CHARACTERIZED BY INCREASINGLY SFC-BASED
   EFFECTIVE INFLOW PARCELS AND STRENGTHENING DEEP-LAYER SHEAR CAUSED
   BY EJECTING SWRN CONUS WAVE.  HODOGRAPHS SHOULD BE SUFFICIENT FOR
   THREAT OF SUPERCELLS AND PERHAPS TORNADOES.  POSSIBLE EVOLUTION TO
   MESSY CONVECTIVE MODES AND LACK OF STRONGER DIABATIC HEATING MAY BE
   LIMITING FACTORS...GIVEN POTENTIAL FOR EARLY ONSET OF CONVECTION AND
   SPREAD OF RELATED CLOUD COVER/PRECIP.
   
   2. NEXT EARLIEST DEVELOPMENT IS LIKELY MIDDAY INTO MID-AFTERNOON
   NEAR SFC LOW AND ADJACENT PORTIONS OF FRONT AND DRYLINE ARC OVER
   KS...WHERE DEEP-LAYER FORCING WILL BE STRONGEST SOONEST WITHIN
   GREAT-PLAINS CORRIDOR.  RATHER LENGTHY HODOGRAPHS PROGGED IN NARROW
   WARM SECTOR MAY SUPPORT SPLITTING STORMS AS WELL.  SUPERCELLS WITH
   LARGE HAIL...SVR GUSTS AND TORNADOES ARE POSSIBLE.  CAPPING WILL BE
   STRONGER FARTHER NE ALONG FRONT AND SE/S ALONG DRYLINE...BUT SVR
   POTENTIAL SHOULD BRANCH OUT ALONG THOSE CORRIDORS DURING AFTERNOON.
   
   3. AHEAD OF DRYLINE OVER PORTIONS SRN KS...OK AND N TX.  DEEP-LAYER
   SHEAR AND MEAN-WIND VECTORS SHOULD BE PROGRESSIVELY MORE ORTHOGONAL
   TO DRYLINE WITH SWD EXTENT AND WITH TIME...CONTRIBUTING TO GREATER
   POTENTIAL FOR RELATIVELY DISCRETE MODES TO LAST LONGER. 
   HOWEVER...PRESENCE OF CLOUD COVER FROM WARM-SECTOR CONVECTION MAY
   RESULT IN NARROW OR RESTRICTED AREA OF AFTERNOON DESTABILIZATION. 
   SOME MASS ADJUSTMENT OF MID-UPPER LEVEL WIND FIELDS ALSO MAY
   OCCUR...RELATED TO EARLIER PERTURBATION AND PRESENCE OF CONVECTION
   FARTHER S...THAT COULD LEAD TO AREAS OF BACKING WITH HEIGHT
   ALOFT...AND POTENTIALLY COMPLEX CONVECTIVE MODES.
   
   ...SERN CONUS...
   ALTHOUGH DEEP-LAYER WINDS AND SHEAR SHOULD BE RATHER WEAK...REMNANT
   STREAMER OF ELEVATED MIXED-LAYER AIR WILL CONTRIBUTE TO FAVORABLE
   STEEP LAPSE RATES NEAR FRONTAL ZONE...FROM APPALACHIANS SEWD TO
   COAST.  STG SFC HEATING OF VERY MOIST WARM-SECTOR AIR MASS WILL LEAD
   TO MLCAPE OVER 2000 J/KG DURING AFTERNOON...SUPPORTING POTENTIAL FOR
   DEVELOPMENT OF STG TSTMS IN CLUSTERS.  ORGANIZATION OF DAMAGING WIND
   THREAT WILL DEPEND ON AGGREGATE COLD-POOL DEVELOPMENT...TAKING
   ADVANTAGE OF WELL-MIXED SUBCLOUD LAYERS.  ATTM POTENTIAL APPEARS TOO
   CONDITIONAL ON MESOSCALE AND SMALLER-SCALE PROCESSES FOR MORE THAN
   MRGL UNCONDITIONAL SVR PROBABILITIES.
   
   ADDITIONAL TSTMS MAY DEVELOP ALONG SEA BREEZES FROM FRONTAL ZONE SWD
   ACROSS FL...ATLANTIC SEA BREEZE BEING PREFERRED CONVECTIVE ZONE
   GIVEN GEOMETRY OF AMBIENT FLOW.  THOUGH STG TURNING WITH HEIGHT WILL
   OCCUR BENEATH NW FLOW ALOFT...LOW-MIDLEVEL WINDS SHOULD BE WEAK OVER
   CENTRAL/SRN FL...AND CAPE WILL BE LIMITED BY WEAK LAPSE RATES ALOFT.
   ATTM SVR POTENTIAL APPEARS TOO DISORGANIZED/MRGL FOR PROBABILITIES.
   
   ..EDWARDS.. 05/10/2011
   
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