Categorical Graphic
Probabilistic Tornado Graphic
Probability of a tornado within 25 miles of a point. Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.
Probabilistic Damaging Wind Graphic
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point. Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
Probabilistic Large Hail Graphic
Probability of hail 1" or larger within 25 miles of a point. Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.

   SPC AC 280100
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0800 PM CDT FRI MAY 27 2011
   
   VALID 280100Z - 281200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS SRN PLAINS/OZARK
   REGION...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS INTERIOR MID-ATLANTIC
   REGION...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS NH/MAINE...
   
   ...SYNOPSIS...
   DOMINANT UPPER-AIR FEATURE FOR REMAINDER PERIOD WILL BE BELT OF STG
   MID-UPPER FLOW FROM NRN CA TO N-CENTRAL PLAINS AND UPPER MS
   VALLEY...DOWNSTREAM FROM DEVELOPING CYCLONE OFFSHORE ORE.  ON NOSE
   OF UPPER JET...SHORTWAVE TROUGH IS INITIALLY OVER DAKOTAS SE OF NERN
   MT LOW.  THIS FEATURE SHOULD MOVE ENEWD ACROSS WI BY 12Z.  AS
   RESULTING HEIGHT FALLS OCCUR ACROSS GREAT LAKES REGION...SEPARATE
   TROUGH OVER CENTRAL APPALACHIANS WILL LIFT NEWD ACROSS INTERIOR
   MID-ATLANTIC REGION AND DEAMPLIFY GREATLY.  SRN-STREAM TROUGH NOW
   OVER GA/CAROLINAS AND NRN FL IS EXPECTED TO MOVE OFFSHORE CAROLINAS
   AND MOST OF FL OVERNIGHT.
   
   AT SFC...DIFFUSE AND CONVECTIVELY MODIFIED FRONTAL ZONE OVER
   APPALACHIANS SHOULD CONTINUE TO WEAKEN GRADUALLY UNDERNEATH GEN
   HEIGHT RISES ALOFT.  SFC LOW WAS ANALYZED ON 23Z CHART IN HBR/CSM
   AREA...WITH DRYLINE ARCHING SEWD BETWEEN SPS-ADM THEN SSWWD TO NRN
   COAHUILA.  LOW SHOULD DRIFT ERRATICALLY OVER SWRN OK AREA OVERNIGHT.
    WEAK COLD/STATIONARY FRONT ARCS FROM SWRN OK LOW ACROSS ERN TX
   PANHANDLE...AND EXTENDS NEWD FROM LOW ACROSS CENTRAL/NERN OK THEN
   EWD OVER OZARKS AS WARM FRONT.  ANOTHER WARM FRONT -- REMNANTS OF
   ERN CONUS BAROCLINIC ZONE...WAS ANALYZED FROM LOW SEWD ACROSS
   E-CENTRAL TX AND LA...AND SHOULD WEAKEN AND MOVE NWD ACROSS RED
   RIVER OVERNIGHT.
   
   ....SRN PLAINS/OZARK REGION...
   THOUGH SOME CINH REMAINED IN 00Z OUN RAOB...MODIFICATIONS TO THAT
   AND TO RUC FCST SOUNDINGS FOR ENVIRONMENT FARTHER NW BETWEEN JWG-END
   INDICATE SUFFICIENTLY WEAK CINH TO SUPPORT POTENTIAL SFC-BASED
   INITIATION NEXT 1-2 HOURS.  VIS IMAGERY ALSO SHOWS DEEP CONVECTIVE
   TOWERS OVER NRN BLAINE COUNTY.  ANY SUSTAINED CONVECTION ARISING
   FROM THAT AREA MAY BECOME SUPERCELLULAR IN ENVIRONMENT OF 50-60 KT
   EFFECTIVE SHEAR MAGNITUDES AND 150-350 J/KG EFFECTIVE SRH.  RISK
   MAINLY IS FOR LARGE HAIL AND SVR GUSTS...WITH TORNADO POTENTIAL VERY
   CONDITIONAL ON STORM-SCALE PROCESSES.
   
   OTHERWISE...TSTM COVERAGE IS EXPECTED TO EXPAND OVERNIGHT ACROSS
   N-CENTRAL/NERN OK AND ADJOINING PORTIONS KS...EWD ACROSS SRN MO. 
   STEEP DEEP-LAYER LAPSE RATES ABOVE STABLE BOUNDARY LAYER WILL BE
   REINFORCED BY LOW-LEVEL WAA.  MEANWHILE MOISTURE ADVECTION/TRANSPORT
   WILL OCCUR WITHIN TRAJECTORIES ACCOMPANYING 35-45 KT LLJ.  RESULT
   SHOULD BE MUCAPE 1000-2000 J/KG AVAILABLE TO PARCELS ISENTROPICALLY
   LIFTED TO LFC.  FCST SOUNDINGS SUGGEST 55-65 KT EFFECTIVE
   SHEAR...SUPPORTING POTENTIAL FOR LARGE HAIL.  ADDITIONALLY...DRY
   LAYERS BETWEEN CLOUD BASE AND SFC MAY SUPPORT ISOLATED STG/DAMAGING
   GUSTS PENETRATING SHALLOW/DIABATICALLY COOLED AIR MASS NEAR SFC.
   
   ...ERN CONUS...
   WIDELY SCATTERED CLUSTERS OF TSTMS PERSIST IN BROAD BELT FROM MAINE
   SWWD ACROSS CENTRAL PA THEN SSWWD OVER WV.  GREATEST CONCENTRATIONS
   NEXT FEW HOURS WILL AFFECT PORTIONS ERN PA/NY...WITH SECONDARY TSTM
   AREA OVER NH/MAINE...EACH OF WHICH MAY PRODUCE DAMAGING WINDS AND
   OCNL HAIL BEFORE DISSIPATING.  ANOTHER CORRIDOR OF
   CLUSTERED/MULTICELLULAR CONVECTION IS APPARENT ATTM FROM SRN NC
   SSWWD ACROSS ERN GA THEN SSEWD ALONG GA/FL SEA BREEZE/OUTFLOW
   BOUNDARIES.  UPPER-LEVEL SUPPORT IS EXPECTED TO DIMINISH THROUGH
   REMAINDER PERIOD AS SHORTWAVE TROUGHS RAPIDLY WEAKEN OR MOVE
   AWAY...RENDERING REMAINING POTENTIAL MORE DEPENDENT ON LOW-LEVEL
   THERMODYNAMIC SUPPORT AND LOCALIZED BOUNDARY EFFECTS THAN PRIOR
   DAYS.  AS SUCH...OVERALL SVR THREAT SHOULD CONTINUE TO DIMINISH AND
   BECOME PROGRESSIVELY MORE FRAGMENTED THROUGH REMAINDER EVENING...DUE
   TO STABILIZING EFFECTS OF BOTH DIABATIC COOLING AND SPREADING
   CONVECTIVE OUTFLOWS.
   
   ..EDWARDS.. 05/28/2011
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0600Z