Aug 3, 2015 1300 UTC Day 1 Convective Outlook
Updated: Mon Aug 3 12:58:39 UTC 2015 (20150803 1300Z Day 1 shapefile | 20150803 1300Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20150803 1300 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 157,024 19,318,814 Pittsburgh, PA...Cincinnati, OH...Lexington-Fayette, KY...Louisville, KY...Rochester, NY...
MARGINAL 421,245 55,883,398 New York, NY...Detroit, MI...Indianapolis, IN...Columbus, OH...Denver, CO...
Probabilistic Tornado Graphic
20150803 1300 UTC Day 1 Tornado Probabilities 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.
Day 1 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
2 % 388,750 39,211,027 Indianapolis, IN...Columbus, OH...Kansas City, MO...St. Louis, MO...Pittsburgh, PA...
Probabilistic Damaging Wind Graphic
20150803 1300 UTC Day 1 Damaging Wind Probabilities 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.
Day 1 Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
15 % 151,485 18,552,032 Pittsburgh, PA...Cincinnati, OH...Lexington-Fayette, KY...Rochester, NY...Syracuse, NY...
5 % 419,340 55,258,861 New York, NY...Detroit, MI...Indianapolis, IN...Columbus, OH...Denver, CO...
Probabilistic Large Hail Graphic
20150803 1300 UTC Day 1 Large Hail Probabilities 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.
Day 1 Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
15 % 124,584 17,123,713 Pittsburgh, PA...Cincinnati, OH...Lexington-Fayette, KY...Louisville, KY...Rochester, NY...
5 % 452,183 56,969,487 New York, NY...Detroit, MI...Indianapolis, IN...Columbus, OH...Denver, CO...
   SPC AC 031258

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0758 AM CDT MON AUG 03 2015

   VALID 031300Z - 041200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS NERN KY TO PORTIONS NEW
   ENGLAND...

   ...THERE IS A MRGL RISK OF SVR TSTMS ELSEWHERE WWD ACROSS MID MS
   VALLEY TO CENTRAL HIGH PLAINS...

   ...SUMMARY...
   A FEW SEVERE STORMS ARE EXPECTED FROM THE NORTHEAST INTO THE OHIO
   VALLEY...ACCOMPANIED BY SEVERE WIND AND/OR HAIL DURING THE
   AFTERNOON. ISOLATED HAIL AND WIND ARE ALSO POSSIBLE ACROSS PORTIONS
   OF THE CENTRAL AND SOUTHERN GREAT PLAINS.

   ...SYNOPSIS...
   IN MID-UPPER LEVELS...SYNOPTIC-SCALE PATTERN IS DOMINATED BY
   CYCLONES OVER NWRN BC AND FAR NRN ONT...WITH INTERMEDIARY MEAN
   RIDGING FROM AB SWD TO NWRN MEX.  WELL-DEFINED SHORTWAVE TROUGH --
   NOW EVIDENT IN MOISTURE-CHANNEL IMAGERY FROM NRN NV ESEWD ACROSS
   CENTRAL UT AND SWRN CO TO NWRN TX PANHANDLE -- HAS EMBEDDED
   VORTICITY MAX/MESOSCALE 500-MB CIRCULATION CENTER OVER CENTRAL UT. 
   THAT VORTICITY MAX IS EXPECTED TO MOVE NNEWD OVER SWRN WY BY
   00Z...WITH TROUGH EXTENDING BOTH SEWD TO SWRN KS/NWRN OK AND WNWWD
   ACROSS SRN ID.  PERTURBATION WILL CONTINUE SLOWLY PENETRATING MEAN
   RIDGE POSITION...SUCH THAT IT LIES FROM W-CENTRAL MT TO SERN WY TO
   NWRN KS TO NERN OK BY END OF PERIOD.

   MEANWHILE...SERIES OF LOW-AMPLITUDE SHORTWAVE TROUGHS WILL ORBIT SRN
   RIM OF ONT VORTEX...WITHIN BELT OF ENHANCED CYCLONIC FLOW EXTENDING
   FROM MB SEWD OVER UPPER OH VALLEY TO NEW ENGLAND.  ONE OF THOSE --
   CURRENTLY EVIDENT OVER LH...LOWER MI...CENTRAL LM AND ERN WI --
   SHOULD PIVOT ESEWD TO LOWER GREAT LAKES AND SRN LM BY 00Z...THEN
   FROM NRN MAINE TO NRN PA OR WRN NY BY 12Z.

   AT SFC...COLD FRONT WAS ANALYZED AT 11Z FROM SRN QUE SWWD ACROSS
   LE...NRN INDIANA...NRN MO...TO KS/NEB BORDER REGION...BECOMING
   QUASISTATIONARY FROM THERE NWWD TO LOW OVER SERN WY.  FRONT SHOULD
   MOVE LITTLE THROUGH PERIOD FROM MO WWD...AND SHOULD DRIFT EWD AND
   SEWD OVER NERN CONUS BEFORE BEING REINFORCED BY SHOT OF
   BOUNDARY-LAYER CAA RELATED TO AFOREMENTIONED GREAT LAKES SHORTWAVE
   TROUGH.

   ...NEW ENGLAND TO OH VALLEY...
   WIDELY SCATTERED TO SCATTERED TSTMS SHOULD DEVELOP GRADUALLY TODAY
   IN WEAKLY CAPPED AIR MASS AHEAD OF SFC COLD FRONT...AS DIABATIC
   HEATING ERODES MLCINH.  SFC DEW POINTS UPPER 50S TO MID 60S F SHOULD
   SUPPORT MLCAPE IN 500-1500 J/KG RANGE OVER NEW ENGLAND AND MID ATLC
   REGIONS.  PEAK MLCAPE SHOULD INCREASE FROM THERE SWWD TO AROUND 3000
   J/KG OVER OH VALLEY...WHERE BOTH LAPSE RATES AND LOW-LEVEL MOISTURE
   WILL BE GREATER AHEAD OF FRONT AND PREFRONTAL OUTFLOW BOUNDARIES
   FROM PRIOR/OVERNIGHT MCS ACTIVITY.  GENERALLY FRONT-PARALLEL AND
   UNIDIRECTIONAL DEEP-LAYER FLOW IS EXPECTED...EXCEPT FOR LOCALIZED
   CROSS-BOUNDARY COMPONENTS AROUND OUTFLOWS.  PREDOMINANT CONVECTIVE
   MODE SHOULD BE MULTICELLULAR...WITH MRGL-SVR HAIL AND OCNL DAMAGING
   GUSTS INTO EARLY EVENING.  SEVERAL LOCALIZED CONCENTRATIONS OF SVR
   ARE MORE PROBABLE WITHIN THIS CORRIDOR RATHER THAN A CONTINUOUS
   STRIP OF HAIL/WIND...REGULATED LARGELY BY MESOBETA-SCALE FACTORS. 
   AFTER EARLY EVENING...DIURNAL/DIABATIC STABILIZATION OF BOUNDARY
   LAYER SHOULD CONTRIBUTE TO LESSENING SVR THREAT.

   ...CENTRAL/SRN PLAINS...
   ISOLATED TO WIDELY SCATTERED TSTMS IN CLUSTERS SHOULD DEVELOP
   THROUGH PERIOD INVOF SFC FRONTAL ZONE AND ON EITHER SIDE OF LEE
   TROUGH THAT WILL REMAIN INVOF SERN WY...CO/KS BORDER AND NRN SEGMENT
   OF TX/NM BORDER.  ISOLATED SVR GUSTS AND HAIL ARE POSSIBLE.

   LARGE-SCALE DCVA/DESTABILIZATION ALOFT WILL SPREAD FROM W-E ACROSS
   HIGH PLAINS IN ADVANCE OF WRN CONUS SHORTWAVE TROUGH...CONTERMINOUS
   WITH SFC HEATING AND IN REGIME CHARACTERIZED BY 50S AND 60S F SFC
   DEW POINTS.  MEANWHILE...THOUGH UNDER INFLUENCE OF STG EML...CAPPING
   MAY WEAKEN SUFFICIENTLY FOR A FEW TSTMS INVOF SFC FRONT...AMIDST
   FRONTAL LIFT AND STG HEATING THIS AFTN.  THOUGH COVERAGE LIKELY WILL
   BE MORE SPARSE/UNCERTAIN INVOF FRONT...CONDITIONAL SVR POTENTIAL IS
   GREATER GIVEN STEEP LAPSE RATES...LARGER CAPE AND STRONGER DEEP
   SHEAR THAN FARTHER SW.  ALTHOUGH LOW/MIDDLE LEVEL FLOW GENERALLY
   WILL BE WEAK OVER HIGH PLAINS REGION...VEERING WITH HEIGHT SHOULD
   CONTRIBUTE TO SUFFICIENT DEEP SHEAR FOR ORGANIZED MULTICELLS AND
   PERHAPS A TRANSIENT SUPERCELL OR TWO WHERE BOUNDARY INTERACTIONS CAN
   CONTRIBUTE.

   ..EDWARDS/DEAN.. 08/03/2015

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z