THERE IS A SLGT RISK OF SVR TSTMS THROUGH LATE EVENING FROM NRN MN SEWD TO NRN VA FOR TODAY

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 041634
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1134 AM CDT WED JUL 04 2012
   
   VALID 041630Z - 051200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS THROUGH LATE EVENING FROM NRN
   MN SEWD TO NRN VA...
   
   ...NRN MN/WI THROUGH THIS EVENING...
   THE PRIMARY NRN STREAM SHORTWAVE TROUGH NOW OVER SK WILL CREST THE
   RIDGE AND BEGIN TO MOVE MORE EWD OVER MB/WRN ONTARIO LATER TODAY
   INTO TONIGHT.  AT THE SURFACE...A LOW IN ERN ND THIS MORNING WILL
   SLOWLY WEAKEN BY LATE EVENING...AS A SURFACE WARM FRONT LIFTS NWD
   ACROSS NRN MN/WI...AND A COLD FRONT PROGRESSES SEWD ACROSS NEB AND
   THE ERN DAKOTAS.  A RESERVOIR OF LOW 70S BOUNDARY LAYER DEWPOINTS
   BENEATH STEEP MIDLEVEL LAPSE RATES...IN COMBINATION WITH DAYTIME
   HEATING...WILL SUPPORT A CORRIDOR OF STRONG INSTABILITY ALONG AND S
   OF THE WARM FRONT IN MN/WI...WHERE MLCAPE WILL RANGE FROM 3000-4000
   J/KG.
   
   ONGOING STORMS ACROSS NW MN SHOULD PERSIST THROUGH THE DAY AND
   SPREAD EWD ACROSS NRN MN...NEAR AND JUST N OF THE WARM FRONT. 
   DEEP-LAYER AND LOW-LEVEL VERTICAL SHEAR WILL BE SOMEWHAT STRONGER ON
   THE IMMEDIATE COOL SIDE OF THE BOUNDARY...WHERE BOTH ORGANIZED
   MULTICELL CLUSTER AND SOME SUPERCELL STRUCTURES WILL BE POSSIBLE. 
   LARGE HAIL AND DAMAGING WINDS WILL BE THE MAIN SEVERE THREATS WITH
   THIS ACTIVITY.  
   
   ...NRN WI TO LOWER MI THIS AFTERNOON/EVENING...
   FARTHER SE ALONG THE WARM FRONT ACROSS WI/LOWER MI...STRONG SURFACE
   HEATING AND STRONG INSTABILITY WILL BE PRESENT.  THE ONLY CLEAR
   FOCUS FOR STORM INITIATION WILL BE LOW-LEVEL CONVERGENCE ALONG THE
   BOUNDARY...WHILE A DIFFUSE SPEED MAX ALOFT MOVES ESEWD FROM WRN
   UPPER MI TOWARD LOWER MI.  STORM COVERAGE REMAINS QUESTIONABLE ALONG
   THIS CORRIDOR...BUT THE STEEP LAPSE RATES/LARGE BUOYANCY WILL
   SUPPORT A CONDITIONAL RISK FOR LARGE HAIL/DAMAGING WINDS...PRIMARILY
   WITH MULTICELL STORMS.
   
   ...ERN OH/WRN PA/WV/NRN VA THIS AFTERNOON/EVENING...
   THE FOCUS FOR STORM DEVELOPMENT IS STILL A BIT UNCERTAIN...BUT
   STRONG SURFACE HEATING IS WELL UNDERWAY ACROSS THE AREA...WHERE
   MODERATE-STRONG INSTABILITY IS EXPECTED THIS AFTERNOON.  THE REMNANT
   COLD POOL WITH THE ONGOING NW PA STORMS COULD BE ASSOCIATED WITH NEW
   STORM DEVELOPMENT THIS AFTERNOON...AS WELL AS SURFACE HEATING OVER
   THE HIGHER TERRAIN.  ANY STORMS/CLUSTERS THAT DO FORM WILL BE
   CAPABLE OF PRODUCING DAMAGING DOWNBURST WINDS...AND SOME HAIL.
   
   ...UPSTATE NY AREA THIS AFTERNOON...
   A SHORTWAVE TROUGH OVER QUEBEC WILL ROTATE SEWD OVER NRN NY/NRN NEW
   ENGLAND THIS AFTERNOON/EVENING...ALONG WITH AN ASSOCIATED SURFACE
   COLD FRONT.  VERTICAL SHEAR WILL BE SUFFICIENT FOR ORGANIZED DEEP
   CONVECTION...BUT POOR LAPSE RATES WILL TEND TO LIMIT BUOYANCY. 
   THUS...WILL MAINTAIN LOW WIND/HAIL PROBABILITIES IN THIS UPDATE.
   PREVIOUS FORECAST REMAINS ON TRACK.
   
   ..THOMPSON/SMITH.. 07/04/2012
   
   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z
   CURRENT UTC TIME: 1639Z (11:39AM), RELOAD THIS PAGE TO UPDATE THE TIME