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 251730
   
   DAY 2 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1230 PM CDT WED JUL 25 2012
   
   VALID 261200Z - 271200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS FROM OH TO PARTS OF THE
   NORTHEAST...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE UPPER GREAT
   LAKES/MID-MS VALLEY NEWD TO SRN NEW ENGLAND...
   
   ...POTENTIAL FOR A WIDESPREAD DAMAGING WIND EVENT/DERECHO ON THU
   AFTERNOON FROM PARTS OF THE MIDWEST TO THE NORTHEAST...
   
   ...SYNOPSIS...
   VIGOROUS SHORT WAVE TROUGH OVER THE SRN CANADIAN PRAIRIES WILL MOVE
   SEWD AND REACH THE UPPER GREAT LAKES BY EARLY FRI...WITH A
   MODERATELY FAST ZONAL FLOW REGIME EXISTING DOWNSTREAM ACROSS THE
   NERN CONUS. AT THE SURFACE...A WARM FRONT WILL ADVANCE NEWD IN THE
   NORTHEAST AND SHOULD REMAIN QUASI-STATIONARY ACROSS THE CNTRL GREAT
   LAKES. A SERIES OF WEAK CYCLONES SHOULD BE PREVALENT ALONG THIS
   BOUNDARY...WHICH WILL INTERSECT A SLOW-MOVING COLD FRONT MOVING SEWD
   FROM THE MID-MS VALLEY TO THE SRN PLAINS. IN THE WEST...MID-LEVEL
   RIDGING WILL BUILD FROM THE SOUTHWEST ACROSS THE INTERMOUNTAIN WEST.
   
   ...MID-MS/OH VALLEYS TO THE NORTHEAST/SRN NEW ENGLAND...
   CONFIDENCE CONTINUES TO GROW WITH POTENTIAL FOR SCATTERED TO
   NUMEROUS ORGANIZED SEVERE TSTMS...PARTICULARLY FROM THE MIDWEST TO
   THE NORTHEAST. AN MCS SHOULD BE ONGOING ACROSS PARTS OF THE LOWER
   GREAT LAKES...SUPPORTED BY AN INITIAL MID-LEVEL SPEED MAX AND ROBUST
   LOW-LEVEL WAA ADVECTION. THIS SHOULD RETARD THE NERN ADVANCEMENT OF
   THE WARM FRONT AND SUBSEQUENT EVOLUTION OF THIS ACTIVITY DOES BREED
   UNCERTAINTY OVER WHERE THE FRONT WILL ULTIMATELY ANCHOR.
   
   AN EXPANSIVE UNCAPPED WARM SECTOR CHARACTERIZED BY 90S/60S SURFACE
   TEMPERATURES/DEW POINTS WILL CONTRIBUTE TO MODERATE TO STRONG
   BUOYANCY THU AFTERNOON WITH MLCAPE OF 2000-4000 J/KG. A LARGE SWATH
   OF 30-50 KT 700-500 MB WLYS WILL OVERLAP THIS INSTABILITY...AND WITH
   WEAK MID-LEVEL HEIGHT FALLS COMBINING WITH FRONTAL
   CONVERGENCE...THIS SETUP WILL YIELD SCATTERED TO NUMEROUS TSTMS
   FORMING ALONG AND AHEAD OF THE COLD FRONT. THE UNIDIRECTIONAL WIND
   PROFILES AND STEEP LOW-LEVEL LAPSE RATES SHOULD SUPPORT UPSCALE
   GROWTH INTO SEVERAL CLUSTERS WITH BOWING SEGMENTS AND EMBEDDED
   SUPERCELL STRUCTURES. DAMAGING WINDS /POTENTIALLY WIDESPREAD AND
   SIGNIFICANT/ WILL BE THE PRIMARY THREAT.
   
   A RELATIVELY NARROW CORRIDOR OF ENHANCED TORNADO RISK SHOULD DEVELOP
   ALONG THE WARM FRONTAL ZONE WHERE EFFECTIVE SRH AND STRONGEST
   DEEP-LAYER SHEAR WILL BE MAXIMIZED. ALTHOUGH PINPOINTING THIS
   CORRIDOR IS DIFFICULT GIVEN LIKELIHOOD OF PRECEDING OVERNIGHT
   CONVECTION...IT APPEARS MOST PROBABLE FROM PARTS OF NY INTO SRN NEW
   ENGLAND. SOME CONVECTION-ALLOWING GUIDANCE SUGGESTS THAT DISCRETE
   CONVECTION MAY FORM WITHIN A PERSISTING WAA REGIME THU AFTERNOON.
   
   ...UPPER GREAT LAKES...
   DCVA DOWNSTREAM OF THE APPROACHING SHORT WAVE TROUGH OVER NRN MN
   SHOULD FOSTER ISOLATED TO SCATTERED TSTMS THU AFTERNOON. THIS
   ACTIVITY SHOULD FORM ALONG/AHEAD OF A SECONDARY COLD FRONT SURGE
   THAT WILL ACT MORE AS A DRYLINE CROSSING THE UPPER MS VALLEY. THE
   COMBINATION OF BUOYANCY/SHEAR SHOULD BE MODEST...BUT SUFFICIENT FOR
   ISOLATED SEVERE HAIL AND LOCALLY DAMAGING WINDS.
   
   ...NRN ROCKIES...
   A BELT OF CONFLUENT MID-LEVEL FLOW WILL STRENGTHEN N OF THE BUILDING
   RIDGE IN THE WEST. ALTHOUGH BUOYANCY WILL REMAIN LIMITED...ISOLATED
   TSTMS SHOULD FORM HIGHER TERRAIN. SUFFICIENT DEEP-LAYER SHEAR WILL
   EXIST FOR A MARGINAL RISK OF SEVERE WIND/HAIL.
   
   ..GRAMS.. 07/25/2012
   
   CLICK TO GET WUUS02 PTSDY2 PRODUCT

   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0600Z