MESOSCALE PRECIPITATION DISCUSSION 0353
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1146 PM EDT TUE JUL 14 2015
 
AREAS AFFECTED...CENTRAL AND NORTHEAST PENNSYLVANIA...SOUTH
CENTRAL NEW YORK...NORTHERN MARYLAND 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 150346Z - 150746Z
 
SUMMARY...SHORT TERM ISOLATED FLASH FLOOD THREAT WITH SLOW MOVING
AND POTENTIAL TRAINING CONVECTION.

DISCUSSION...RADAR AND IR/WV LOOP SHOWS WELL DEVELOPING SURFACE
LOW/OCCLUSION ACROSS WESTERN PA UNDER THE UPPER LEVEL CENTER OF
THE SHORTWAVE. SHORTWAVE RIDGING ACROSS NORTHERN PA/SOUTHERN NEW
YORK HAS INCREASED AND WITH EASTWARD MOTION OF THE UPPER
LOW...WILL ALLOW FOR RELATIVELY SLOWER FLOW PARTIALLY DIVERGENT
WITH JET ENTRANCE ACROSS NEW ENGLAND.  THIS IS ALLOWING FOR A
TIGHTER DEFORMATION ZONE TO BE ESTABLISHED FROM NEAR UNV NORTHEAST
BETWEEN BGM/MSV. SURFACE TO DEEP LAYER CONVERGENCE FIELDS
MAXIMIZING WITH INCREASED NORTHERLY FLOW BEHIND THE DEFORMATION
ZONE...COINCIDENT WITH 500-1000 J/KG MUCAPES ON THE EASTERN SIDE
OF THE BOUNDARY ALLOWS FOR A RECENT UPTICK IN CONVECTIVE
DEVELOPMENT PER IR AND RADAR LOOPS.  MODERATE MOISTURE
AVAILABILITY WITH THIS CONVECTIVE GROWTH SHOULD SUPPORT RATES OF
1-1.5"/HR. LOW LEVEL FLOW AHEAD OF THE TRIPLE POINT NEAR UNV...IS
OUT OF THE SOUTH-SOUTHWEST DEEP ENOUGH TO ALLOW FOR A WEAK CLOUD
BEARING PROFILE FOR SOME SPOT TRAINING/REPEAT AS IT IS GENERALLY
PARALLEL TO THE DEFORMATION ZONE...THIS SHOULD BE SUPPORTED OVER A
FEW HOURS BEFORE SLOW EASTWARD PROGRESS OF THE BOUNDARY OCCURS.  
HI-RESOLUTION MODELS SUCH AS THE HRRR SHOW INCREASED COVERAGE AND
SUGGEST A PATTERN OF SPOT TRAINING WITH TOTALS OVER 2"
POSSIBLE...GIVEN TERRAIN AND SOME LOWER FLASH FLOOD GUIDANCE...
THE POSSIBILITY FOR FLASH FLOODING WILL BE SPOTTY BUT POSSIBLE
OVER THE NEXT FEW HOURS.   

GALLINA

ATTN...WFO...ALY...BGM...CTP...LWX...PHI...

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

LAT...LON   42197507 41887446 41097506 40337581 39527624 
            39437696 39667767 40147773 40417786 40717782 
            41177748 41877584