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 132016
   
   DAY 1 CONVECTIVE OUTLOOK AMEND 1
   NWS STORM PREDICTION CENTER NORMAN OK
   0316 PM CDT THU OCT 13 2011
   
   VALID 132008Z - 141200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FOR ERN AND NRN VA INTO THE
   DELMARVA...
   
   AMENDED TO ADD LOW TORNADO PROBS
   
   ADDED 5% TORNADO PROBABILITIES FOR A SMALL PORTION OF VA...MD AND
   DE. A FEW STRONGER STORMS WILL MOVE NEAR THE BAROCLINIC
   ZONE/BOUNDARY MENTIONED IN THE PREVIOUS OUTLOOK. LOCALIZED SHEAR IN
   THIS VICINITY MAY RESULT IN A WEAK AND BRIEF TORNADO OR TWO.
   
   ------------------------------------------------------------------
   
   ...AL/GA...
   SCATTERED LOW TOPPED THUNDERSTORMS EMBEDDED WITHIN A MODESTLY STRONG
   WLY FLOW REGIME WILL HAVE A THREAT OF STRONG WIND GUSTS ACROSS AL
   AND GA THROUGH THE AFTERNOON. FOR MORE INFORMATION SEE MESOSCALE
   DISCUSSION 2253.
   
   ...MID ATLANTIC...
   POCKETS OF HEATING HAVE RESULTED IN GRADUAL DESTABILIZATION FROM NC
   INTO THE DELMARVA WITH DEEPENING CU FIELDS. A GRADUALLY DEEPENING
   SURFACE TROUGH COMBINED WITH HEIGHT FALLS AS THE MAIN UPPER VORT
   CENTER APPROACHES WILL MAINTAIN FAVORABLE WIND PROFILES FOR A FEW
   SUPERCELLS AND/OR SMALL BOWS CAPABLE OF DAMAGING WINDS. A BRIEF
   TORNADO CANNOT BE RULED OUT ESPECIALLY WITH STORMS AS THEY CROSS THE
   WARM FRONT WHICH CURRENTLY IS ACCOMPANIED BY EFFECTIVE SRH OF
   100-150 M2/S2. RELATIVELY BROAD AND WEAK FORCING ACROSS THE WARM
   SECTOR IS EXPECTED TO KEEP SEVERE STORM COVERAGE DOWN...RESULTING IN
   A CONTINUED SEE TEXT AREA.
   
   ADDED A 5% HAIL AREA FROM ERN NC INTO THE DELMARVA WHERE STRONGER
   INSTABILITY EXISTS AND WHERE SPORADIC MARGINAL HAIL CORES APPEAR
   POSSIBLE.
   
   ..JEWELL.. 10/13/2011
   
   .PREV DISCUSSION... /ISSUED 1135 AM CDT THU OCT 13 2011/
   
   ...CNTRL GULF STATES TO SERN ATLANTIC COAST AND NWD INTO THE MID
   ATLANTIC STATES...
   
   STRONG VORTICITY MAXIMUM ON POLEWARD SIDE OF 80-90 KT MIDLEVEL JET
   STREAK OVER THE LOWER MS VALLEY WILL CONTINUE ESEWD...CONTRIBUTING
   TO FURTHER AMPLIFICATION OF NEGATIVELY TILTED LARGE-SCALE TROUGH
   WHICH WILL EXTEND FROM CNTRL CANADA TO SERN ATLANTIC COAST BY
   14/12Z.  IN THE LOW LEVELS...ASSOCIATED COLD FRONT WILL ADVANCE EWD
   FROM THE TN VALLEY AND CNTRL GULF COAST STATES TO OFF THE MIDDLE AND
   SERN ATLANTIC COASTS BY FRI MORNING.
   
   12Z OBSERVED SOUNDINGS FROM THE LOWER MS VALLEY SHOWED A PRONOUNCED
   MIDLEVEL INVERSION ASSOCIATED WITH A SHARP THERMAL GRADIENT
   COINCIDENT WITH UPPER-LEVEL JET STREAK.  AND DESPITE THE PRESENCE OF
   A MOIST AND WARMING PRE-FRONTAL WARM SECTOR...FORECAST SOUNDINGS
   INDICATE THAT THIS INVERSION WILL SPREAD EWD TODAY...LIMITING THE
   DEPTH AND MAGNITUDE OF POTENTIAL BUOYANCY.  THE COUPLING OF DCVA IN
   ADVANCE OF VORTICITY MAXIMUM AND FRONTAL UPLIFT WILL PROMOTE A
   GRADUAL INCREASE IN STORMS THROUGH THE DIURNAL HEATING CYCLE WITHIN
   A KINEMATIC ENVIRONMENT FEATURING A STEADILY STRENGTHENING WLY
   UNIDIRECTIONAL WIND FIELD.  THIS SETUP WILL SUPPORT EVOLUTION OF
   STORMS INTO BROKEN LINES WITH LOCALLY DAMAGING WIND GUSTS BEING THE
   PRIMARY HAZARD.
   
   A SEPARATE AREA OF SEVERE STORM POTENTIAL WILL EXIST FROM ERN NC NWD
   ALONG THE MID ATLANTIC COAST THIS AFTERNOON INTO TONIGHT.  WATER
   VAPOR IMAGERY SHOWS A WEAK MIDLEVEL IMPULSE OVER THE CAROLINAS WHICH
   WILL PROGRESS NNEWD AND COMBINE WITH A DIVERGENT UPPER-LEVEL FLOW
   FIELD TO SUPPORT AN INCREASE IN STORMS ACROSS THE REGION.  VISIBLE
   SATELLITE IMAGERY SUGGESTS THAT FAIRLY WIDESPREAD CLOUDINESS WILL
   LIMIT DAYTIME HEATING.  BUT...THE PRESENCE OF A MOIST AIR MASS WILL
   SUPPORT POCKETS OF MODEST DESTABILIZATION WITH AFTERNOON MLCAPE
   VALUES RISING TO 1000-1500 J/KG.  THIS INSTABILITY WILL ALIGN WITH A
   STEADILY STRENGTHENING LOW- TO MID-TROPOSPHERIC WIND FIELD WITH THE
   ENVIRONMENT BECOMING FAVORABLE FOR EMBEDDED BOWING AND SUPERCELL
   STRUCTURES WITH AN ATTENDANT RISK FOR LOCALLY DAMAGING WIND GUSTS
   AND PERHAPS A BRIEF TORNADO.
   
   IT STILL APPEARS THAT THE WEAK LAPSE RATES AND MODEST LOW-LEVEL
   SHEAR WILL LIMIT THE POTENTIAL FOR A MORE ROBUST SUPERCELL/TORNADO
   THREAT.  HOWEVER...ENVIRONMENTAL AND CONVECTIVE TRENDS WILL BE
   MONITORED FOR A POSSIBLE OUTLOOK UPGRADE AT 20Z.
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z