MESOSCALE PRECIPITATION DISCUSSION 0201
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
332 PM EDT MON JUL 14 2014
 
AREAS AFFECTED...CENTRAL/EASTERN PA...EASTERN WV...NORTHERN
VA...MD...FAR NORTHERN DE...NJ...SOUTHEAST NY...CT 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 141930Z - 150030Z
 
SUMMARY...HEAVY SHOWERS AND THUNDERSTORMS WILL BECOME MORE
ORGANIZED THROUGH THE EARLY EVENING. VERY INTENSE RAINFALL RATES
WILL PROMOTE SHORT-TERM FLASH FLOOD CONCERNS.

DISCUSSION...THE LATEST VIS SAT IMAGERY SHOWS AN INCREASINGLY
AGITATED CU/TCU FIELD OVER MUCH OF SERN PA AND DOWN INTO CNTRL MD
AND NRN VA AS STRONG DIURNAL HEATING CONTINUES, THIS COUPLED WITH
A VERY MOIST BOUNDARY LAYER IS SUPPORTING A NOSE OF SBCAPE VALUES
OVER 3000 J/KG OVER NRN VA AND CNTRL MD. THE LATEST GOES-SOUNDER
PWATS ARE NEAR 2 INCHES THROUGHOUT THE MID-ATLANTIC REGION AND UP
INTO SRN NEW ENGLAND...AND THIS IS ALL POOLED OUT AHEAD OF A COLD
FRONT THAT IS SLOWLY APPROACHING FROM THE LWR GRT LAKES REGION.

OVER THE NEXT SEVERAL HOURS...THERE SHOULD BE AN INCREASE IN
CONVECTIVE ORGANIZATION GIVEN STRONGER DIURNAL HEATING AND THE
APPROACH OF SOMEWHAT STRONGER MID LVL WLY FLOW OUT AHEAD OF A
LARGE SCALE TROUGH/CLOSED LOW DROPPING DOWN FROM THE UPR MIDWEST
AND GRT LAKES REGION. MULTIPLE BANDS OF MULTICELL CONVECTION CAN
BE EXPECTED...WITH THE POTENTIAL FOR SOME CELL-MERGERS AND CELL
TRAINING GIVEN THE LINEAR MODE OF THE EXPECTED CONVECTIVE ACTIVITY.

SINCE THERE IS SUCH A DEEP LAYER OF MOISTURE IN PLACE...RAINFALL
RATES ARE EXPECTED TO BE VERY HIGH AND WILL LIKELY BE ON THE ORDER
OF 2 TO 3 INCHES/HR. THIS COUPLED WITH ANY TRAINING AND
INTERACTION WITH TOPOGRAPHY WILL PROMOTE EXCESSIVE AMTS. THEREFORE
FLASH FLOODING WILL BE POSSIBLE THROUGH THE EVENING.

ORRISON

ATTN...WFO...BOX...OKX...ALY...PHI...BGM...CTP...LWX...PBZ...

ATTN...RFC...MARFC...NERFC...OHRFC...

LAT...LON   41387187 40357327 39627502 39007665 38627816 39137916
            39827910 40207858 41007665 41707484 42037303 41387187