Sep 2, 2014 1300 UTC Day 1 Convective Outlook
Updated: Tue Sep 2 12:41:07 UTC 2014 (20140902 1300Z Day 1 shapefile | 20140902 1300Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20140902 1300 UTC Day 1 Outlook Graphic
Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 103,313 11,904,724 Pittsburgh, PA...Lexington-Fayette, KY...Syracuse, NY...Scranton, PA...Utica, NY...
Probabilistic Tornado Graphic
20140902 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.
Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Probabilistic Damaging Wind Graphic
20140902 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.
Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
15 % 103,585 11,891,578 Pittsburgh, PA...Lexington-Fayette, KY...Syracuse, NY...Scranton, PA...Utica, NY...
5 % 288,866 45,817,553 Columbus, OH...Memphis, TN...Baltimore, MD...Washington, DC...Oklahoma City, OK...
Probabilistic Large Hail Graphic
20140902 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.
Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
5 % 127,288 9,163,304 Memphis, TN...Oklahoma City, OK...Tulsa, OK...Wichita, KS...Little Rock, AR...
   SPC AC 021241

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0741 AM CDT TUE SEP 02 2014

   VALID 021300Z - 031200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS TODAY FROM ERN KY NEWD TO
   CENTRAL NY...

   ...SUMMARY...
   A FEW DAMAGING GUSTS WILL BE POSSIBLE FROM THE EASTERN KENTUCKY AREA
   NORTHEASTWARD TO CENTRAL NEW YORK...MAINLY THIS AFTERNOON.  OTHER
   ISOLATED STRONG TO SEVERE STORMS WILL BE POSSIBLE FROM THE MID SOUTH
   TO OKLAHOMA TODAY...AND INTO KANSAS OVERNIGHT.

   ...SYNOPSIS...
   WITHIN A LARGELY ZONAL FLOW REGIME...A SHORTWAVE TROUGH OVER ERN IA
   THIS MORNING WILL PROGRESS EWD TO THE LOWER GREAT LAKES THIS EVENING
   AND NRN NEW ENGLAND OVERNIGHT.  UPSTREAM...ANOTHER SHORTWAVE TROUGH
   WILL MOVE ESEWD FROM VANCOUVER ISLAND TO THE NRN ROCKIES.  AT THE
   SURFACE...A WEAK COLD FRONT WILL MOVE INTO WRN NY/PA THIS AFTERNOON
   AND EVENING.  THE BOUNDARY WILL BECOME MORE DIFFUSE WITH SWWD
   EXTENT...ASIDE FROM WHERE IT IS BEING REINFORCED BY ONGOING
   CONVECTION IN OK.  THIS WRN PORTION OF THE EFFECTIVE BOUNDARY WILL
   MOVE SEWD WITH CONVECTIVE OUTFLOW TODAY...BUT THEN STALL AND THEN
   MOVE NWD AS A WARM FRONT OVERNIGHT INTO KS.

   ...OH VALLEY TO NY TODAY...
   ONGOING CONVECTION ACROSS THE LOWER OH VALLEY MAY PERSIST INTO THE
   DAY WHILE DEVELOPING ESEWD TOWARD ERN KY/WV.  IN THE WAKE OF THIS
   CONVECTION...SOME REDUCTION IN LOW-LEVEL MOISTURE AND RESIDUAL CLOUD
   COVER CAST DOUBT ON THE DEGREE OF DESTABILIZATION AND RENEWED
   THUNDERSTORM DEVELOPMENT ALONG THE WEAK SYNOPTIC FRONT.  THE SAME
   PRE-FRONTAL BAND OF CONVECTION BECOMES MORE DIFFUSE INTO OH...BUT
   COULD STILL ACT AS THE PRIMARY FOCUS FOR THUNDERSTORM DEVELOPMENT
   DURING THE DAY INTO WRN PA/NY.  THOUGH LAPSE RATES WILL BE
   POOR...68-70 F BOUNDARY LAYER DEWPOINTS AND SOME DAYTIME HEATING
   WILL SUPPORT MLCAPE OF 500-1500 J/KG.  THIS BUOYANCY WILL COINCIDE
   WITH AN ENHANCED BELT OF MIDLEVEL FLOW ACCOMPANYING THE SHORTWAVE
   TROUGH /40-50 KT IN THE 700-500 MB LAYER/...THUS A FEW DAMAGING
   GUSTS WILL BE POSSIBLE WITH CLUSTERS/LINE SEGMENTS PRIOR TO
   CONVECTION WEAKENING BY LATE EVENING.

   ...OK TO MID SOUTH TODAY...AND KS TONIGHT...
   CONVECTION IS ONGOING IN OK...THE CONVECTION SHOULD WEAKEN LATER
   THIS MORNING AS THE SWLY LLJ WEAKENS AND MOISTURE INFLUX INTO THE
   CONVECTION IS REDUCED.  FARTHER E...STORMS COULD REGENERATE ALONG
   THE OUTFLOW AS IT SPREADS SEWD TOWARD ERN AR/NW MS WHERE THE RICHER
   MOISTURE AND WEAKER CAP RESIDE COMPARED TO AREAS FARTHER W.  THE
   STORMS WILL ALSO BE MOVING INTO AN AREA WITH WEAKER VERTICAL
   SHEAR...WHICH SUGGESTS THAT ISOLATED DOWNBURSTS WILL BE THE MAIN
   THREAT AFTER THIS MORNING.

   OUTFLOW WITH THE OK STORMS WILL SAG S OF THE STRONGER FLOW
   ALOFT/VERTICAL SHEAR...AND IT IS NOT CLEAR IF NEW SURFACE-BASED
   STORMS WILL FORM THIS AFTERNOON ALONG THE OUTFLOW BOUNDARY IN
   CENTRAL OK GIVEN A STRONG CAP NOTED IN THE 12Z OUN SOUNDING.  THE
   MORE PROBABLE SCENARIO IS FOR ELEVATED STORMS TO FORM TONIGHT IN KS
   AS THE SURFACE BOUNDARY LIKELY ASSUMES WARM FRONTAL CHARACTERISTICS
   AND THE NOCTURNAL SLY LLJ STRENGTHENS.  ISOLATED LARGE HAIL WILL BE
   THE MAIN THREAT WITH ANY OVERNIGHT CONVECTION IN KS.

   ..THOMPSON/MOSIER.. 09/02/2014

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