MESOSCALE PRECIPITATION DISCUSSION 0172
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
300 PM EDT WED JUL 02 2014
 
AREAS AFFECTED...FAR SOUTHEAST NY...CT...RI...MA...VT...NH...ME 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 021855Z - 022300Z
 
SUMMARY...INCREASING SHOWER AND THUNDERSTORM ACTIVITY IS EXPECTED
THROUGH THE AFTERNOON. MERGING CELLS AND THE RISK FOR TRAINING
CONVECTIVE BANDS WILL ENHANCE THE THREAT FOR FLASH FLOODING.

DISCUSSION...THE LATEST IR SAT IMAGERY SHOWS STRONG AND
INCREASINGLY ORGANIZED COLD-TOPPED CONVECTIVE BANDS IMPACTING AN
AREA EXTENDING FROM NORTHEAST PA THROUGH SOUTHEAST NY AND INTO
WESTERN MA AND SOUTHERN VT. THESE BANDS OF CONVECTION ARE BECOMING
INCREASINGLY ALIGNED WITH THE SOUTHWESTERLY MEAN STEERING FLOW
AHEAD OF AN UPPER TROUGH AND ASSOCD COLD FRONT.

THE LATEST VIS IMAGERY SHOWS AN INCREASINGLY AGITATED AND
EXPANSIVE CU/TCU FIELD ALONG THE EASTERN SLOPES OF THE NORTHERN
APPALACHIANS FROM CENTRAL/SOUTHERN NH NORTHEAST INTO CENTRAL ME.
THE AIRMASS OUT AHEAD OF THE FRONT AND ACTIVE AREAS OF CONVECTION
IS BECOMING VERY UNSTABLE...WITH SBCAPE VALUES OF 3000 TO 4000
J/KG ALONG AND WEST OF THE I-95 CORRIDOR AND EXTENDING AS FAR
NORTHEAST AS SOUTHERN ME.

CONVECTION ALREADY ONGOING OVER THE INTERIOR OF THE NORTHEAST WILL
CONTINUE TO ORGANIZE AND ADVANCE NORTHEAST WITH THE APPROACH OF
THE FRONT AND UPPER TROUGH. ADDITIONAL DIURNAL HEATING/SFC-BASED
INSTABILITY COUPLED WITH AN ANOMALOUSLY MOIST AIRMASS WILL PROVIDE
A VERY FAVORABLE THERMODYNAMIC ENVIRONMENT FOR A SUSTAINABLE AND
ORGANIZED CONVECTIVE THREAT THROUGH THE AFTERNOON.

GIVEN PWATS AS PER LATEST GOES-SOUNDER OF 1.75 TO 2 INCHES EAST OF
THE APPALACHIANS...RAINFALL RATES WILL BE VERY INTENSE...AND
POSSIBLY AS HIGH AS 2 TO 3 INCHES/HR. THE SOUTHWESTERLY NATURE TO
THE LOW AND MID LVL FLOW AHEAD OF THE FRONT WILL TEND TO FAVOR A
THREAT FOR TRAINING CELLS...AND CELL MERGERS WILL BE LIKELY IN THE
SHORT TERM AS CONVECTION BECOMES BETTER ORGANIZED. THE THREAT FOR
FLASH FLOODING WILL BE ELEVATED...AND ESP OVER AREAS OF HIGHER
TERRAIN. WILL CONTINUE TO MONITOR.

ORRISON

ATTN...WFO...CAR...GYX...BOX...BTV...OKX...ALY...

ATTN...RFC...NERFC...

LAT...LON   43277427 44237257 45067133 45557071 45966962 45896833
            45156775 44126831 42536989 41277124 40687247 40947366
            42177269 42577264 42967288 43147321 43147398 43277427