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 310532
   
   DAY 2 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1232 AM CDT TUE MAY 31 2011
   
   VALID 011200Z - 021200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE NERN STATES INTO THE
   MID ATLANTIC AND SRN APPALACHIANS...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM A PORTION OF THE CNTRL AND
   NRN PLAINS INTO THE UPPER MS VALLEY...
   
   ...SYNOPSIS...
   
   NRN PERIPHERY OF SRN U.S. SUBTROPICAL HIGH WILL REMAIN SUPPRESSED BY
   PROGRESSIVE UPPER TROUGH THAT WILL MOVE FROM THE GREAT LAKES INTO
   QUEBEC AND NERN STATES WEDNESDAY. FARTHER UPSTREAM ANOTHER UPPER LOW
   WILL MOVE FARTHER INTO THE WESTERN STATES. A COLD FRONT WILL
   ACCOMPANY THE UPPER TROUGH THROUGH NERN U.S. WHILE TRAILING PORTION
   OF THIS BOUNDARY WILL RETURN NWD AS A WARM FRONT THROUGH THE CNTRL
   PLAINS.
   
   ...NERN STATES THROUGH MID ATLANTIC AND SRN APPALACHIANS AREA...
   
   WARM FRONT WILL SHIFT EWD THROUGH NEW ENGLAND WITH MID-UPPER 60S
   DEWPOINTS ADVECTING THROUGH WARM SECTOR BENEATH REMNANT EML. THIS
   WILL RESULT IN MODERATE INSTABILITY FROM THE NERN STATES INTO THE
   MID ATLANTIC. DEEP LAYER WINDS AND VERTICAL SHEAR WILL GRADUALLY
   STRENGTHEN AS UPPER TROUGH ADVANCES THROUGH THE GREAT LAKES AND SRN
   CANADA WITH STRONGER SHEAR OVER THE NERN STATES. STORMS WILL LIKELY
   DEVELOP AHEAD OF FRONT AS THE BOUNDARY LAYER WARMS DURING THE DAY.
   MULTICELL AND SUPERCELL STORM STRUCTURES ARE EXPECTED WITH
   SUPERCELLS MORE LIKELY TOWARD NRN NEW ENGLAND. THE PRIMARY THREATS
   ARE EXPECTED TO BE DAMAGING WIND AND LARGE HAIL.
   
   OTHER STORMS WILL LIKELY DEVELOP DURING THE AFTERNOON SWD INTO THE
   SRN APPALACHIANS. VERTICAL SHEAR WILL BE MUCH WEAKER IN THIS REGION
   DUE TO PROXIMITY OF UPPER RIDGE...BUT DIABATIC WARMING OF THE MOIST
   BOUNDARY LAYER AND STEEP /7-7.5 C/KM/ MID LEVEL LAPSE RATES WILL
   RESULT IN STRONG /2000-3000 J/KG/ MLCAPE. STORMS THAT DEVELOP IN
   THIS ENVIRONMENT WILL BE PULSE AND MULTICELL IN NATURE BUT WILL BE
   CAPABLE OF ISOLATED DOWNBURSTS AND LARGE HAIL.
   
   ...NEB...SD...IA AND SRN MN...
   
   THE ATMOSPHERE WILL BECOME QUITE UNSTABLE ALONG AND SOUTH OF WARM
   FRONT AS RICHER MOISTURE RETURNS NWD BENEATH STEEP LAPSE RATES. SOME
   UNCERTAINTY STILL EXISTS REGARDING EXTENT OF SURFACE BASED
   INITIATION DURING THE DAY. WEAK UPPER RIDGE WILL BUILD IN WAKE OF
   UPPER TROUGH MOVING THROUGH THE GREAT LAKES WHICH IN CONJUNCTION
   WITH EWD EXPANDING EML SUGGEST THE MOIST WARM SECTOR COULD
   POTENTIALLY REMAIN CAPPED OR SURFACE BASED STORM COVERAGE MIGHT BE
   LIMITED. A FEW STORMS WILL BE POSSIBLE NEAR WARM FRONT DURING PEAK
   AFTERNOON HEATING OVER A PORTION OF CNTRL NEB WHERE DEEPER VERTICAL
   SHEAR AND LOW LEVEL HODOGRAPHS WILL PROMOTE SUPERCELLS WITH ISOLATED
   TORNADOES AND VERY LARGE HAIL. OTHERWISE ELEVATED STORMS WILL LIKELY
   DEVELOP OVERNIGHT NORTH OF WARM FRONT WITHIN ZONE OF ISENTROPIC LIFT
   FROM ERN SD...NWRN IA INTO SRN MN WHERE THE THERMODYNAMIC
   ENVIRONMENT AND EFFECTIVE SHEAR WILL BE SUFFICIENT FOR HAILSTORMS.
   
   ...WRN KS AND ERN CO THROUGH SRN HIGH PLAINS...
   
   DEEP MIXING ALONG WRN EDGE OF RICHER MOISTURE WILL LIKELY PROMOTE A
   FEW STORMS DEVELOPING FROM THE SRN THROUGH CNTRL HIGH PLAINS. HAVE
   INTRODUCED A CATEGORICAL RISK FOR THE CNTRL HIGH PLAINS WHERE DEEP
   LAYER SHEAR IS FORECAST TO BE SUFFICIENT FOR ROTATING HIGH BASED
   STORMS WITH A THREAT FOR ISOLATED LARGE HAIL AND DAMAGING WIND
   THROUGH EARLY EVENING. VERTICAL SHEAR WILL DECREASE WITH SWD EXTENT
   INTO THE SRN PLAINS...BUT STEEP LAPSE RATES AND MODERATE INSTABILITY
   WILL SUPPORT A THREAT OF ISOLATED LARGE HAIL AND DOWNBURSTS.
   
   ...REMAINDER OF THE SERN STATES...
   
   WIDELY SCATTERED TO SCATTERED STORMS WILL BE POSSIBLE DURING THE
   AFTERNOON WITH GREATEST COVERAGE EXPECTED ALONG THE APPALACHIANS.
   WEAK VERTICAL SHEAR BENEATH UPPER RIDGE WILL PROMOTE MULTICELL AND
   PULSE STORMS...BUT STEEP LAPSE RATES AND MODERATE INSTABILITY WILL
   SUPPORT A THREAT OF ISOLATED DOWNBURSTS AND HAIL THROUGH EARLY
   EVENING.
   
   ...NRN ROCKIES AREA...
   
   COLD AIR ALOFT...STEEP LAPSE RATES AND DIABATIC WARMING WILL RESULT
   IN MARGINAL MLCAPE FROM THE PACIFIC NW INTO THE NRN ROCKIES AREA.
   DEEPER FORCING FOR ASCENT WITH IMPULSES ROTATING ALONG ERN PERIPHERY
   OF LARGE UPPER LOW WILL PROMOTE SCATTERED STORMS DEVELOPING DURING
   THE DAY. ACTIVITY WILL BE EMBEDDED WITHIN 40-50 KT EFFECTIVE SHEAR.
   STRONGER STORMS COULD PRODUCE ISOLATED HAIL AND STRONG WIND GUSTS
   INTO THE EVENING...BUT LIMITED LOW LEVEL MOISTURE AND MARGINAL
   INSTABILITY PRECLUDES MORE THAN 5% SEVERE PROBABILITIES.
   
   ..DIAL.. 05/31/2011
   
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   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z