SPC AC 130559

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1259 AM CDT FRI MAY 13 2016

   VALID 131200Z - 141200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS FROM EASTERN KS THROUGH
   CENTRAL/NORTHERN MO AND SOUTHERN IA TO WESTERN IL...

   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS EASTERN NC AND FAR
   SOUTHEAST VA...

   ...THERE IS A MRGL RISK OF SVR TSTMS SURROUNDING A SLGT RISK AREA
   FROM NORTHERN AND EASTERN IL TO WESTERN OK AND NORTHWEST TX
   INCLUDING THE TX/OK PANHANDLES...

   ...THERE IS A MRGL RISK OF SVR TSTMS EXTENDING FROM SOUTHERN
   DELMARVA REGION TO SOUTHEAST GA AND NORTH FL...

   ...SUMMARY...
   STRONG TO SEVERE STORMS...CAPABLE PRIMARILY OF A RISK FOR LARGE HAIL
   AND DAMAGING WIND GUSTS...ARE FORECAST FROM EASTERN KANSAS INTO THE
   MIDDLE MISSISSIPPI VALLEY THIS AFTERNOON.  ADDITIONALLY...A FEW
   STRONG TO SEVERE STORMS WILL BE POSSIBLE ACROSS SOUTHEAST VIRGINIA
   AND EASTERN NORTH CAROLINA INTO THIS AFTERNOON.  ISOLATED LARGE HAIL
   MAY OCCUR FRIDAY NIGHT FROM NORTHWEST TEXAS INTO WESTERN OKLAHOMA. 
   MEANWHILE...ISOLATED STORMS CAPABLE OF A FEW LOCALLY STRONG WIND
   GUSTS MAY OCCUR FROM EASTERN SOUTH CAROLINA TO NORTH FLORIDA.

   ...SYNOPSIS...
   AN UPPER RIDGE WILL BE MAINTAINED ACROSS THE WESTERN STATES...WHILE
   AMPLIFICATION IS EXPECTED EAST OF THE ROCKIES WITH THE EASTERN U.S.
   LONGWAVE TROUGH.  A COLD FRONT...ATTENDANT TO A LEAD SHORTWAVE
   TROUGH MOVING THROUGH THE MID-ATLANTIC AND NORTHEAST STATES...WILL
   APPROACH THE EASTERN SEABOARD BY EVENING AND THEN MOVE OFFSHORE MUCH
   OF THE EAST COAST.  ANOTHER FRONTAL SURGE IS EXPECTED TO ADVANCE
   SOUTHEAST AND SOUTH FROM THE NORTHERN PLAINS AND UPPER MS VALLEY TO
   THE OH VALLEY...MID SOUTH AND NORTH TX BY 12Z SATURDAY.

   ...EASTERN KS TO MID MS VALLEY THIS AFTERNOON AND EVENING...
   A SURFACE LOW LOCATED ALONG THE PLAINS COLD FRONT IS EXPECTED TO
   ADVANCE SOUTHEAST FROM CENTRAL NEB TO NORTHERN MO BY MID-LATE
   AFTERNOON AND THEN TRACK EAST THROUGH CENTRAL IL TO NORTHERN
   INDIANA.  ALTHOUGH THE PRE-FRONTAL AIR MASS IS EXPECTED TO BE DRY
   INITIALLY...A NARROW PLUME OF RETURN FLOW AHEAD OF THE COLD FRONT
   WILL RESULT IN SURFACE DEW POINTS IN THE MID 50S REACHING EASTERN KS
   TO WEST-CENTRAL IL.  SURFACE HEATING COMBINED WITH THIS MOISTURE
   RETURN BENEATH THE EASTERN EXTENT OF AN EML /STEEP MIDLEVEL LAPSE
   RATES/ SHOULD RESULT IN MLCAPE OF 500-1000 J/KG.  DESPITE MODEST
   INSTABILITY...STRENGTHENING DEEP-LAYER WIND FIELDS AND BULK SHEAR
   SUGGEST STORM ORGANIZATION WILL BE LIKELY AS CONVECTION DEVELOPS
   ALONG THE COLD FRONT.  THE CAPE/SHEAR PARAMETER SPACE AND INVERTED-V
   THERMODYNAMIC PROFILES WILL RESULT IN DAMAGING WINDS AND HAIL BEING
   THE PRIMARY THREATS.  HOWEVER...A 40-45 KT SOUTHWESTERLY LOW-LEVEL
   JET DEVELOPING THIS AFTERNOON FROM EASTERN KS TO WESTERN IL SUGGESTS
   A TORNADO THREAT CANNOT BE RULED OUT...MAINLY DURING THE EARLY
   EVENING PRIOR TO WEAKENING CONVECTION.  DURING THAT TIME FRAME...THE
   BOUNDARY LAYER IS FORECAST TO MOISTEN WHILE LOW-LEVEL HODOGRAPH
   CURVATURE INCREASES.

   ...SOUTHEAST VA AND EASTERN NC THROUGH THE AFTERNOON TO EARLY
   EVENING...
   HEIGHT FALLS AND DPVA ATTENDANT TO THE SOUTHERN EXTENT OF THE LEAD
   SHORTWAVE TROUGH ARE EXPECTED TO SPREAD ACROSS THE WARM SECTOR IN
   SOUTHEAST VA AND EASTERN NC THROUGH THIS AFTERNOON.  PRE-DAY 1
   CONVECTION...CURRENTLY LOCATED OVER SOUTHEAST NC AND EASTERN
   SC...SHOULD BE LOCATED ALONG OR OFF THE ATLANTIC COAST AT 12Z TODAY.
   BREAKS IN THE CLOUDS BETWEEN THIS EARLY DAY ACTIVITY AND THE COLD
   FRONT SHOULD PROVE FAVORABLE FOR SUFFICIENT DIABATIC HEATING OF A
   MOIST BOUNDARY LAYER...RESULTING IN MLCAPE OF 1000-1500 J/KG. 
   MODELS SUGGEST CONVECTION SHOULD DEVELOP BY LATE MORNING AS WEAK
   INHIBITION DIMINISHES.  EFFECTIVE BULK SHEAR OF 35-40 KT WILL
   SUPPORT STORM ORGANIZATION WITH DAMAGING WINDS THE PRIMARY THREAT AS
   ONE OR MORE BANDS OF STORMS MOVES FROM WEST TO EAST ACROSS FAR
   SOUTHEAST VA AND EASTERN NC THIS AFTERNOON.  ISOLATED HAIL CANNOT BE
   RULED OUT...THOUGH MODEST MIDLEVEL LAPSE RATES SUGGEST THE
   PROBABILITY OF HAIL EXCEEDING SEVERE VALUES SHOULD BE LOW.

   ...EASTERN SC TO NORTHERN FL THROUGH THE AFTERNOON...
   A FEW STRONG TO SEVERE STORMS WILL BE POSSIBLE WITH SOUTHWARD EXTENT
   ALONG AND AHEAD OF THE COLD FRONT AS THE ENVIRONMENT ACROSS THESE
   AREAS WILL BE MODERATELY UNSTABLE...THOUGH SHOULD HAVE WEAKER BULK
   SHEAR.

   ...NORTHWEST TX TO WESTERN OK FRIDAY NIGHT...
   RICHER LOW-LEVEL MOISTURE WILL RETURN NORTHWARD BENEATH EML PLUME
   CONTRIBUTING TO MODERATE INSTABILITY OVERNIGHT FROM NWRN TX INTO WRN
   OK.  FRONTOGENETIC FORCING ASSOCIATED WITH THE SOUTHWARD-ADVANCING
   COLD FRONT INTERACTING WITH A MODEST INCREASE IN THE LLJ SHOULD
   RESULT IN THE DEVELOPMENT OF STORMS LATE FRIDAY NIGHT.  MUCH OF THE
   ACTIVITY WILL PROBABLY REMAIN ELEVATED IN FRONTAL ZONE WITH HAIL THE
   PRIMARY THREAT.

   ..PETERS/BUNTING.. 05/13/2016

   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z