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 081229
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0729 AM CDT WED JUN 08 2011
   
   VALID 081300Z - 091200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE GREAT LAKES SWWD INTO
   IA/NRN MO AND WWD THROUGH THE CENTRAL PLAINS TO NERN CO/SERN WY...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE NORTHEAST
   STATES...
   
   ...SYNOPSIS...
   CONFLUENT FLOW RESULTING IN TROUGH INITIALLY UPPER MS VALLEY
   SHEARING EWD ACROSS GREAT LAKES TOWARD NRN NEW ENGLAND BY END OF
   PERIOD.  WITH STRONGEST FLOW REMAINING ALONG/N OF US/CAN BORDER AND
   LITTLE IN THE WAY OF HEIGHT FALLS...CONVECTIVE INHIBITION WILL DELAY
   SEVERE THUNDERSTORM DEVELOPMENT UNTIL LATER THIS AFTERNOON AND MORE
   LIKELY TONIGHT ACROSS NERN US AS WARM UNSTABLE AIR SPREADS EWD INTO
   WRN NEW ENGLAND.
   
   SURFACE LOW MOVING EWD FM LS ACROSS SRN ONTARIO WITH A TRAILING COLD
   FRONT FROM NWRN WI THRU IA TO NWRN KS/ERN CO WILL BE A FOCUS FOR
   CONVECTIVE INITIATION LATER TODAY ONCE CINH CAN BE REMOVED THRU
   STRONG DAYTIME HEATING..
   
   UPPER LOW PAC NW DROPS SEWD INTO SRN ID TONIGHT AND IN THE PROCESS A
   WEAKER S/WV MOVES EWD FROM SRN CA TO AZ/WRN NM TONIGHT.
   
   ..NERN PA/ERN NY INTO NRN NEW ENGLAND...
   WARM FRONT EXTENDING SWD FROM THE SURFACE LOW MOVING THROUGH
   SRN ONTARIO/QUEBEC TODAY WILL ADVANCE CONCURRENTLY EWD AND SHOULD
   REACH WRN NEW ENGLAND BY MID-LATE AFTERNOON. THIS WILL ALLOW A MOIST
   AND POTENTIALLY VERY UNSTABLE AIR MASS TO SPREAD EWD FROM OH VALLEY
   TO WRN NEW ENGLAND BY THIS AFTERNOON AS DEWPOINTS RISE
   INTO THE MID-UPPER 60S. IN THE PRESENCE OF STRONG HEATING AND STEEP
   MID LEVEL LAPSE RATES...MLCAPES WILL CLIMB TO AOA 2500 J/KG MUCH OF
   INTERIOR NERN U.S.  GIVEN THE LACK OF ANY APPRECIABLE FORCING WITH
   THE PASSING UPPER TROUGH S OF THE BORDER...AFTERNOON SEVERE
   THUNDERSTORM POTENTIAL WILL BE TIED TO THE STRONG HEATING OF HIGHER
   TERRAIN. THE SEVERE THREAT POTENTIALLY COULD INCREASE DURING THE
   EVENING AS THE COLD FRONT MOVES ACROSS SWRN ONTARIO AND THE ST
   LAWRENCE VALLEY AND WHICH WILL BE A POSSIBLE FOCUS FOR SEVERE MCS
   DEVELOPMENT.
   
   EFFECTIVE BULK SHEAR OF 25-30 KT WILL TEND TO SUPPORT
   MULTICELLS WITH HAIL/DAMAGING WINDS THE PRIMARY THREATS.  THE
   PRESENCE OF STEEP MIDLEVEL LAPSE RATES AND DEGREE OF INSTABILITY
   SUGGEST SOME OF THE HAIL COULD BE VERY LARGE.  AN ISOLATED TORNADO
   CANNOT BE RULED OUT...GIVEN VERTICALLY VEERING WIND PROFILES WITH
   LOW LEVEL SHEAR STRENGTHENING FROM NY INTO MAINE AS A WLY LLJ
   INCREASES  BY EVENING NEAR THE CANADIAN BORDER.
   
   THE SEVERE WEATHER THREAT ACROSS NRN NEW ENGLAND WILL MAINLY BE
   ASSOCIATED WITH ONE OR MORE CLUSTERS OF STORMS SPREADING ESEWD INTO
   THAT AREA FROM CANADA.  MODERATE INSTABILITY AND STRONGER DEEP LAYER
   SHEAR WITH NEWD EXTENT SHOULD PROVE FAVORABLE FOR A GREATER
   POTENTIAL FOR SUPERCELLS.
   
   ...GREAT LAKES TO IA/NRN MO SWWD TO CENTRAL PLAINS...
   DESPITE WEAK OVERALL FORCING ALOFT FOR ASCENT ACROSS THIS PART OF
   THE SLIGHT RISK AREA...THE PRE-COLD FRONTAL ENVIRONMENT IS EXPECTED
   TO BECOME MODERATELY TO STRONGLY UNSTABLE /MLCAPE 2000-3500 J PER
   KG/ BY THIS AFTERNOON.
   
   SURFACE BASED STORMS ARE FORECAST TO DEVELOP BY MID TO LATE
   AFTERNOON ACROSS WI INTO UPPER AND NRN LOWER MI AHEAD OF THE
   ADVANCING COLD FRONT. ACTIVITY WILL THEN FORM SWWD ALONG THE FRONT
   INTO KS.  SHEAR ACROSS THIS REGION WILL BE FAVORABLE FOR MAINLY
   MULTICELLS...THOUGH SUPERCELL STORMS WILL BE POSSIBLE WITH NWD
   EXTENT ACROSS THE WRN GREAT LAKES WHERE EFFECTIVE BULK SHEAR WILL BE
   STRONGER.  LARGE HAIL...SOME VERY LARGE...AND DAMAGING WINDS WILL BE
   POSSIBLE WITH STRONGER STORMS.
   
   ...CENTRAL HIGH PLAINS...
   THE PRESENCE OF STEEP MIDLEVEL LAPSE RATES AND STRONG SURFACE
   HEATING ALONG THE FRONT RANGE OF NERN CO/SERN WY TODAY COMBINED WITH
   POST-FRONTAL UPSLOPE FLOW AND SWLY FLOW ALOFT WILL RESULT IN AN
   SHEAR ENVIRONMENT FAVORABLE FOR TSTM DEVELOPMENT...WITH SUPERCELLS
   LIKELY. ALTHOUGH INSTABILITY WILL BE MARGINAL /MLCAPE AOB 500 J PER
   KG/...DUE TO LIMITED MOISTURE...MODELS AGREE THAT OVERALL TSTM
   COVERAGE WILL BE SUFFICIENT TO MAINTAIN A SLIGHT RISK OF SEVERE
   STORMS.
   
   ..HALES/HURLBUT.. 06/08/2011
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z