MESOSCALE PRECIPITATION DISCUSSION 0295
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
253 PM EDT THU JUN 02 2016
 
AREAS AFFECTED...CENTRAL APPALACHIANS...SHENANDOAH VALLEY AND
ADJACENT FOOTHILLS 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 021825Z - 030000Z
 
SUMMARY...HEAVY SHOWERS AND THUNDERSTORMS DEVELOPING OVER THE
EASTERN SLOPES OF THE CENTRAL APPALACHIANS WILL BE SLOW MOVING
THROUGH LATE AFTERNOON AND MAY PRODUCE SOME ENHANCED RUNOFF
CONCERNS AND FLASH FLOODING.

DISCUSSION...GIVEN THE INCREASE IN SOLAR INSOLATION/DIABATIC
HEATING THROUGH THE AFTERNOON...A SUFFICIENT AMOUNT OF SURFACE
BASED INSTABILITY HAS BEEN ATTAINED TO INITIATE CONVECTION OVER
THE HIGHER TERRAIN OF THE CENTRAL APPALACHIANS. MUCH OF THE FOCUS
IS OVER THE EASTERN SLOPES OF THE TERRAIN COURTESY OF A RELATIVELY
MOIST AND UNSTABLE LOW LEVEL SOUTHEAST FLOW.

PWATS ARE ON THE ORDER OF 1.25 TO 1.5 INCHES AND THIS COUPLED WITH
OROGRAPHIC FORCING AND A POOL OF MODERATE INSTABILITY WITH SBCAPE
VALUES NEAR AND WEST OF THE SHENANDOAH VALLEY EXCEEDING 2000
J/KG...SHOULD ENHANCE RAINFALL RATES. EXPECTING RAINFALL RATES TO
APPROACH 2 INCHES/HR WITH THE DEVELOPING ACTIVITY.

OVER THE NEXT FEW HOURS...THE CONVECTION AS DENOTED IN HIRES
GUIDANCE SUCH AS THE ARW AND NMMB SHOULD BEGIN TO SLOWLY ADVANCE
EAST INTO THE FOOTHILLS OF THE MID-ATLANTIC. THE SLOW CELL MOTION
THOUGH IS LIKELY TO CAUSE SOME RUNOFF PROBLEMS AND POTENTIAL FOR
FLASH FLOODING AND ESPECIALLY WITH THE WATER CHANNELING EFFECTS OF
THE HIGHER TERRAIN.

EXPECT RAINFALL AMOUNTS THROUGH 00Z TO BE ON THE ORDER OF 3 TO 4
INCHES WITHIN THE STRONGER AND MORE SUSTAINABLE CORES.

ORRISON

ATTN...WFO...CTP...LWX...MRX...PBZ...RLX...RNK...

ATTN...RFC...LMRFC...MARFC...OHRFC...SERFC...

LAT...LON   40457779 39627782 38547850 37587936 36768032 
            36318111 36398181 36698197 36688259 36988264 
            37388184 38178062 39007968 40367852