MESOSCALE PRECIPITATION DISCUSSION 0465
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1050 AM EDT THU JUL 14 2016
 
AREAS AFFECTED...NY...VT...WESTERN MA...NORTHWEST CT...NORTHERN
NJ...NORTHEAST PA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 141450Z - 142050Z
 
SUMMARY...HIGHLY EFFICIENT THUNDERSTORMS TO INCREASE IN COVERAGE
ACROSS WET ANTECEDENT CONDITIONS MAY SUPPORT ISOLATED FLASH
FLOODING CONCERNS. 

DISCUSSION...AS NOTED IN SPC MCD 1272 ROBUST DIABATIC HEATING HAS
INCREASED INSTABILITY INTO THE 1500 RANGE (MLCAPES) WITH SURFACE
TDS IN THE UPPER 60S AND LOW 70S AND WITH STRONG DPVA FROM
IMPRESSIVE SHORTWAVE ACROSS W NY IS ALREADY STARTING TO SPARK
SCATTERED CONVECTIVE CORES ALONG THE ENHANCING SURFACE TROF ACROSS
CENTRAL PA INTO S CENTRAL NY.   ADDITIONAL RAP/OBSERVATIONAL
MOISTURE PARAMETERS HIGHLIGHTED BY THE 12Z ALB SOUNDING INDICATE
VERY DEEP RICH MOISTURE AHEAD OF THE SHORTWAVE WITH TPWS IN THE
1.75-2" RANGE WITH HIGH FREEZING LEVELS AND LOW WBZ SPREAD WILL
SUPPORT EFFICIENT RAINFALL PRODUCTION WITH THESE CORES.  NEARLY
UNIDIRECTIONAL FLOW THOUGH FAST SHOULD SUPPORT LINE CLUSTERS THAT
MAY HAVE SOME ADDITIONAL DURATION TO THIS HIGH RAIN RATES.  THIS
IS SUGGESTIVE OF 1-2"/HR TOTALS LIKELY WITH ISOLATED TOTALS NEAR
3" POSSIBLE TOWARD 21-22Z AS THE ENTIRE LINE EXPANDS IN COVERAGE
ACROSS THE HUDSON VALLEY/ADIRONDACKS.  THIS IS SUPPORTED BY MUCH
OF THE HI-RES GUIDANCE SUITE PARTICULARLY THE LAST 2-3 RUNS OF THE
HRRR AND HRRR PARALLEL (VER.2).

ADDITIONAL CONCERN FOR FLASH FLOODING MAY EXIST ACROSS THE
CATSKILLS AND GIVEN THE ANTECEDENT CONDITIONS FROM LAST WEEK'S
HEAVY RAINFALL...LEADING TO 1HR VALUES AT OR BELOW 1"...WHICH EVEN
IN DEVELOPMENTAL STAGES OF CELLS MAY BE EXCEEDED. 

GALLINA

ATTN...WFO...ALY...BGM...BTV...OKX...PHI...

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

LAT...LON   44997186 44827169 44487202 43967230 43447253 
            43157260 42967275 42807306 42387321 41807329 
            41197372 40987394 40747449 40827495 41157550 
            41237595 41647618 42057670 42587638 42897611 
            43557490 44017410 44967254