Categorical Graphic
Probabilistic Tornado Graphic
Probabilistic Damaging Wind Graphic
Probabilistic Large Hail Graphic

   SPC AC 101631
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1131 AM CDT TUE JUN 10 2008
   
   VALID 101630Z - 111200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS THIS AFTERNOON FOR NRN
   VA...MD...ERN PA...CENTRAL/ERN NY...VT...NH...NW CT...NW MA...NW
   NJ...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK FROM
   NEW ENGLAND TO THE CENTRAL APPALACHIANS...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON INTO TONIGHT
   FROM SE MT TO SW MN...
   
   ...NE STATES THROUGH EARLY TONIGHT...
   CUMULUS DEVELOPMENT IN VISIBLE IMAGERY AND SURFACE OBSERVATIONS WITH
   TEMPERATURES OF 85-90 F SUGGEST THAT CONVECTIVE INHIBITION IS
   WEAKENING AND THUNDERSTORM COVERAGE IS EXPECTED TO INCREASE QUICKLY
   THIS AFTERNOON.  THE PRIMARY FOCUS FOR DEVELOPMENT WILL BE A
   PRE-FRONTAL TROUGH FROM CENTRAL/ERN NY INTO ERN PA/NRN VA.  STEEP
   LOW-LEVEL LAPSE RATES AND MLCAPE VALUES AOA 2500 J/KG WILL BE COMMON
   E OF THE SURFACE TROUGH...WHILE 40-50 KT FLOW IN THE LOW-MID LEVELS
   WILL CONTRIBUTE TO A FAVORABLE ENVIRONMENT FOR BOW ECHOES WITH
   WIDESPREAD DAMAGING WINDS...AS WELL AS LARGE HAIL.  LOW-LEVEL SHEAR
   WILL BE SOMEWHAT STRONGER FROM NRN NY TO VT/NH...WHERE THE THREAT
   FOR SUPERCELLS AND A COUPLE OF TORNADOES WILL BE SOMEWHAT GREATER
   THIS AFTERNOON COMPARED TO AREAS FARTHER SW.
   
   FARTHER S...THUNDERSTORM DEVELOPMENT WILL BE DELAYED UNTIL LATER
   THIS AFTERNOON INTO VA.  AFTERNOON SURFACE TEMPERATURES APPROACHING
   100 F AND MAINTENANCE OF AT LEAST MID-UPPER 60 DEWPOINTS WILL RESULT
   IN FAVORABLE PROFILES FOR DAMAGING DOWNBURSTS...DESPITE SOMEWHAT
   WEAKER FLOW ALOFT/VERTICAL SHEAR COMPARED TO AREAS FARTHER N IN NY. 
   CONVECTION SHOULD ORGANIZE THIS AFTERNOON INTO A BROKEN BAND ALONG
   THE LEE TROUGH AND THEN SPREAD EWD WITH THE THREAT FOR DAMAGING
   WINDS.  OTHER STORMS MAY ALSO FORM FARTHER TO THE W OVER THE HIGHER
   TERRAIN...AND ALONG THE SURFACE COLD FRONT.  
   
   ...SE MT THIS AFTERNOON TO ERN SD/SW MN LATE TONIGHT...
   A DEEP MID LEVEL LOW OVER ERN WA/ORE/ID THIS MORNING WILL PROGRESS
   ESEWD TO THE NRN/CENTRAL ROCKIES BY TONIGHT.  DOWNSTREAM FROM THIS
   LOW AND A 50-70 KT MID LEVEL JET...STRONG LEE CYCLOGENESIS WILL
   OCCUR ACROSS THE CENTRAL/NRN HIGH PLAINS THIS AFTERNOON INTO
   TONIGHT.  THIS WILL INDUCE A STRONG SLY LLJ OVER THE CENTRAL PLAINS
   LATE TODAY INTO TONIGHT...WHICH WILL DRAW LOW-LEVEL MOISTURE AND A
   RESIDUAL BAROCLINIC ZONE NWD FROM TX/OK TO NEB/SD BY THE END OF THE
   PERIOD.  
   
   LOW-LEVEL MOISTURE WILL BE SOMEWHAT LIMITED TO THE N OF THE
   DEVELOPING LEE CYCLONE THIS AFTERNOON INTO WRN SD/SE MT /BOUNDARY
   LAYER DEWPOINTS ONLY MID 40S/...AND CLOUDS WILL LIMIT SURFACE
   HEATING ACROSS SRN MT.  HOWEVER...STEEP MID LEVEL LAPSE RATES/COOL
   MID LEVEL TEMPERATURES SHOULD RESULT IN SBCAPE OF 500-1000 J/KG AND
   LITTLE CONVECTIVE INHIBITION.  A FEW THUNDERSTORMS SHOULD FORM OVER
   SE MT BY MID-LATE AFTERNOON IN THE NARROW CORRIDOR OF INSTABILITY N
   OF THE LEE CYCLONE AND E OF A COLD FRONT SURGING EWD IN CONJUNCTION
   WITH THE DEEP MID LEVEL LOW.  VERTICAL SHEAR WILL BE SUFFICIENT FOR
   SUPERCELLS GIVEN RELATIVELY LONG/STRAIGHT HODOGRAPHS...WITH LARGE
   HAIL/DAMAGING GUSTS THE MAIN THREATS.
   
   OVERNIGHT...STRONG LOW-LEVEL WAA WILL BE FOCUSED ON THE NOSE OF A
   60-70 KT LLJ ACROSS SD...IN ADVANCE OF THE SURFACE LOW.  A CLUSTER
   OF ELEVATED THUNDERSTORMS WILL LIKELY SPREAD EWD FROM THE HIGH
   PLAINS TOWARD ERN SD/SW MN BY 06-12Z.  FORECAST SOUNDINGS SUPPORT A
   THREAT FOR ELEVATED SUPERCELLS AND/OR BOWING SEGMENTS WITHIN THE
   CONVECTIVE CLUSTER.  STEEP MID LEVEL LAPSE RATES AND INCREASING
   LOW-LEVEL MOISTURE WILL RESULT IN THE DEVELOPMENT OF STRONG
   INSTABILITY /MUCAPE VALUES IN EXCESS OF 2000 J/KG BASED NEAR 800
   MB/...WHICH WILL BE FAVORABLE FOR LARGE HAIL.  STEEP MID LEVEL LAPSE
   RATES AND DCAPE APPROACHING 1000 J/KG COULD SUPPORT INTENSE
   DOWNDRAFTS OF MID LEVEL ORIGINS AND AN ATTENDANT THREAT FOR DAMAGING
   WINDS...DESPITE THE ELEVATED NATURE OF THE UPDRAFTS. 
   
   ...WRN KS THIS AFTERNOON/EVENING...
   LOW-LEVEL MOISTURE IS RETURNING NWD FROM TX/OK TO KS AS A LEE TROUGH
   DEEPENS ACROSS THE HIGH PLAINS.  MORNING SOUNDINGS SUGGEST THAT
   LOW-MID 90S WILL BE SUFFICIENT TO MINIMIZE CONVECTIVE INHIBITION
   ALONG THE LEE TROUGH/DRYLINE BY MID-LATE AFTERNOON...AND ISOLATED
   THUNDERSTORM DEVELOPMENT WILL BE POSSIBLE.  EXPECTED INSTABILITY AND
   VERTICAL SHEAR WILL SUPPORT SUPERCELLS...AND A SMALL SLGT RISK MAY
   BECOME NECESSARY BY THE 20Z UPDATE IF CONFIDENCE IN CONVECTIVE
   INITIATION INCREASES.
   
   ...FL PENINSULA TODAY...
   UPPER LOW INVOF CENTRAL FL WILL CONTINUE TO SUPPORT WIDESPREAD
   THUNDERSTORM DEVELOPMENT WITH 500 MB TEMPS NEAR -10 C. DESPITE WEAK
   FLOW...STEEPER LAPSE RATES THAN NORMAL OWING TO COOL TEMPS ALOFT AND
   NUMEROUS SEA BREEZE/OUTFLOW MERGERS WILL SUPPORT MORE VIGOROUS
   UPDRAFTS SUPPORTIVE OF SEVERE HAIL IN A MODERATELY TO VERY UNSTABLE
   ATMOSPHERE BY AFTERNOON. ISOLATED DAMAGING DOWNBURSTS CAN ALSO BE
   EXPECTED WITH THE MORE INTENSE STORMS.
   
   ...WI/MI TODAY...
   THE PROSPECTS FOR ORGANIZED SEVERE STORMS ACROSS WI/MI APPEAR TO BE
   RATHER MARGINAL THIS AFTERNOON.  THE STRONGER LEAD SHORTWAVE IS
   MOVING OVER LOWER MI NOW...WITH A SOMEWHAT WEAKER UPSTREAM WAVE
   MOVING EWD ACROSS NRN WI.  VEERED LOW-LEVEL FLOW WILL LIMIT
   CONVERGENCE ALONG THE FRONT SAGGING SWD INTO NRN WI AND UPPER
   MI...WHILE LOW-LEVEL DRYING WILL LIMIT INSTABILITY THIS AFTERNOON. 
   ISOLATED HAIL/WIND NEAR SEVERE LEVELS WILL STILL BE POSSIBLE THIS
   AFTERNOON...BUT THE OVERALL THREAT DOES NOT APPEAR TO WARRANT A SLGT
   RISK.
   
   ..THOMPSON/HURLBUT.. 06/10/2008
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z