SPC AC 190731

   DAY 3 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0231 AM CDT FRI SEP 19 2014

   VALID 211200Z - 221200Z

   ...NO SVR TSTM AREAS FORECAST...

   ...SUMMARY...
   NUMEROUS SHOWERS AND A ISOLATED STRONGER THUNDERSTORMS ARE POSSIBLE
   FROM THE EASTERN GREAT LAKES AND NORTHEAST TO THE OHIO VALLEY ON
   SUNDAY. SCATTERED THUNDERSTORMS ARE ALSO EXPECTED ACROSS THE
   INTERIOR WEST...ALONG THE RIO GRANDE VALLEY...AND OVER FLORIDA.

   ...SYNOPSIS...
   SURFACE HIGH PRESSURE WILL EXPAND FROM THE NORTHERN PLAINS AND UPPER
   MS VALLEY TO THE MIDWEST/LOWER OH VALLEY AND EVENTUALLY PARTS OF THE
   SOUTHERN PLAINS THROUGH EARLY MONDAY. A COLD FRONT MARKING THE
   LEADING EDGE OF THE CONTINENTAL POLAR AIRMASS AND ASSOCIATED WITH A
   STRONG AND PROGRESSIVE MID/UPPER TROUGH WILL SPREAD EAST ACROSS
   PA/NY AND NEW ENGLAND...AND SOUTHEAST ACROSS THE OH VALLEY...THROUGH
   SUNDAY EVENING. AN UPPER RIDGE WILL HOLD FIRM ACROSS THE
   SOUTH-CENTRAL U.S. WHILE A CLOSED LOW MIGRATES NORTHEASTWARD ACROSS
   THE GREAT BASIN...FROM NV/UT INTO SOUTHERN ID. THE GREATEST
   POTENTIAL FOR MORE ORGANIZED AND PERSISTENT THUNDERSTORMS THIS
   PERIOD WILL EXIST WITH THE COLD FRONT MOVING FROM THE GREAT LAKES TO
   UPPER OH VALLEY AND PA/NY...AND WITH THE CLOSED LOW CRESTING THE
   RIDGE OVER THE GREAT BASIN.

   ...UPPER OH VALLEY/CENTRAL APPALACHIANS TO NY...
   LIFT ALONG THE FRONT SHOULD BE SUSTAINED BY RELATIVELY STRONG HEIGHT
   FALLS SPREADING EAST FROM THE EASTERN GREAT LAKES TO NEW ENGLAND.
   MARGINAL INSTABILITY IS FORECAST ALONG AND IN ADVANCE OF THE
   BOUNDARY WHERE LAPSE RATES ARE NOT PARTICULARLY STEEP AND LOW LEVEL
   MOISTURE WILL BE LIMITED. NONETHELESS...FORCED ASCENT AND ADEQUATE
   CLOUD-LAYER SHEAR MAY ACT TO OFFSET THE LACK OF GREATER
   DESTABILIZATION AND CONTRIBUTE TO NARROW BANDS/LINES OF FASTER
   MOVING CONVECTION. SOME STORMS COULD PRODUCE SCATTERED STRONGER WIND
   GUSTS. MOST FAVORABLE JUXTAPOSITION OF FORCING/SHEAR/WEAK
   INSTABILITY AND FRONTAL TIMING APPEARS OVER SOUTHERN TIER OF NY
   SOUTHWESTWARD ACROSS PA TO WV AND EASTERN OH DURING SUNDAY
   AFTERNOON.

   ...GREAT BASIN...
   LARGE-SCALE ASCENT AND CYCLONICALLY CURVED MID-LEVEL WIND MAX
   25-35KT WILL LIKELY ACCOMPANY THE MID/UPPER LOW TRACKING OVER NV/UT
   DURING THE AFTERNOON. DIURNAL HEATING AND POCKETS OF STRONGER
   EFFECTIVE SHEAR ON THE ORDER OF 30KT SHOULD CONTRIBUTE TO AN
   INCREASE IN HIGH-BASED STORMS AND SOME CHANCE FOR MARGINALLY SEVERE
   HAIL AND GUSTY SURFACE WINDS.

   ..CARBIN.. 09/19/2014

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   NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0730Z