Categorical Graphic
Probabilistic 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 220600
   
   DAY 2 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0100 AM CDT FRI APR 22 2011
   
   VALID 231200Z - 241200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE MID MS VALLEY REGION
   SWWD INTO TX...
   
   ...SYNOPSIS...
   A NRN STREAM MID-LEVEL TROUGH INITIALLY OVER THE UPPER GREAT LAKES
   IS FORECAST TO MOVE RAPIDLY ENEWD ACROSS SERN CANADA AND NRN NEW
   ENGLAND...WITH THE ASSOCIATED SURFACE CYCLONE PROGGED LIKEWISE TO
   MOVE ENEWD...ACROSS QUEBEC THROUGH THE AFTERNOON AND EVENING.
   
   AS THIS OCCURS...A COLD FRONT WILL BECOME DRAPED WSWWD ACROSS THE
   MIDWEST/OH VALLEY INTO THE SRN PLAINS -- WITH THIS FRONT TO BE THE
   MAIN FOCUS FOR SHOWERS AND THUNDERSTORMS ACROSS THE U.S. THROUGH THE
   PERIOD.
   
   ...MID MS VALLEY SWWD INTO CENTRAL TX...
   CONVECTION WILL LIKELY BE ONGOING ACROSS PORTIONS OF THE AREA --
   MAINLY FROM THE ARKLATEX REGION NEWD...AS LINGERING NOCTURNAL STORMS
   CONTINUE SHIFTING ENEWD ALONG THE FRONTAL ZONE.  MULTIPLE EPISODES
   OF ADDITIONAL CONVECTION WILL BE LIKELY...AS LOCAL
   HEATING/DESTABILIZATION RESULTS IN THE DEVELOPMENT OF 1000 TO 2000
   J/KG MIXED-LAYER CAPE THROUGH THE AFTERNOON.
   
   WITH FLOW ALOFT MODESTLY STRONG AND QUASI-UNIDIRECTIONAL -- BUT
   PARALLEL TO THE BOUNDARY...SHEAR WILL BE SUFFICIENT FOR ORGANIZED
   STORMS BUT PROPENSITY FOR CONVECTION TO MOVE REPEATEDLY ACROSS THE
   SAME AREAS SHOULD HINDER OVERALL POTENTIAL.  NONETHELESS..STRONGER
   CELLS/CLUSTERS WILL BE CAPABLE OF PRODUCING LOCALLY-DAMAGING WINDS
   AND HAIL.  GREATEST TORNADO THREAT -- THOUGH APPEARING QUITE LIMITED
   ATTM -- MAY EXIST ACROSS ERN OK/WRN AR...WHERE A WEAK SURFACE
   FRONTAL WAVE MAY EVOLVE.  HERE...THE RESULTING WEAK BUT LOCALLY
   BACKED SURFACE FLOW MAY PROVIDE LOW-LEVEL SHEAR SUFFICIENT FOR
   SLIGHTLY-GREATER TORNADO POTENTIAL.
   
   FARTHER SWWD INTO TX...A LESS CONVECTIVELY CONTAMINATED AIRMASS IS
   EXPECTED...BUT CAPPING COMBINED WITH VERY WEAK FORCING ALOFT SHOULD
   LIMIT OVERALL CONVECTIVE COVERAGE.  STILL...WITH VERY STEEP LAPSE
   RATES ALOFT...LOCAL CAP BREACHES RESULTING IN CONVECTIVE INITIATION
   WILL LIKELY OCCUR.  THESE ISOLATED CELLS -- DEVELOPING IN AN
   UNSTABLE/SHEARED ENVIRONMENT...WOULD LIKELY BECOME SUPERCELLS --
   POSING A THREAT FOR LARGE HAIL AND LOCALLY DAMAGING WINDS.  THE
   THREAT MAY CONTINUE INTO THE EVENING...THOUGH MOST CONVECTION SHOULD
   SHIFT NWD INTO A MORE ELEVATED REGIME AS LOW-LEVEL JET
   DEVELOPS...SPREADING MORE WIDESPREAD UVV N OF THE FRONTAL ZONE INTO
   N TX/OK.
   
   
   ...MID-ATLANTIC REGION WSWWD INTO THE OH VALLEY...
   CONFLUENT FLOW ALOFT IS PROGGED ACROSS THIS REGION...SUGGESTING
   LITTLE SUPPORT FOR LARGE-SCALE ASCENT.  HOWEVER...AS A COLD FRONT
   SHIFTS ACROSS ERN CANADA AND LAGS SWWD INTO THE OH VALLEY...SHOWERS
   AND SCATTERED THUNDERSTORMS ARE EXPECTED.  AGAIN -- LACK OF MORE
   FAVORABLE CONDITIONS ALOFT SHOULD HINDER MORE APPRECIABLE/WIDESPREAD
   SEVERE POTENTIAL.  HOWEVER...WITH WSWLY FLOW ALOFT SUPPORTING A FEW
   STRONGER UPDRAFTS -- WHICH WILL BE OCCURRING IN MODESTLY-UNSTABLE
   AIRMASS...THREAT FOR LOCALLY GUSTY WINDS AND MARGINAL HAIL JUSTIFIES
   CONTINUATION OF LOW SEVERE WEATHER PROBABILITY ACROSS THIS REGION.
   
   ..GOSS.. 04/22/2011
   
   CLICK TO GET WUUS02 PTSDY2 PRODUCT

   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z