MESOSCALE PRECIPITATION DISCUSSION 0393
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1109 PM EDT TUE JUN 28 2016
 
AREAS AFFECTED...MAINE...NEW HAMPSHIRE...VERMONT 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 290315Z - 290915Z
 
SUMMARY...DESPITE REDUCED INSTABILITY...STRONG FORCING AND
SATURATED ENVIRONMENT WITH POTENTIAL CELL TRAINING TO CONTINUE FF
THREAT THROUGH EARLY MORNING.  

DISCUSSION...MAIN DRIVING SHORTWAVE CURRENTLY LOCATED BETWEEN
OTTAWA AND MONTREAL IS PIVOTING IN ADVANCE OF STRONGER WAVE NEAR
BUFFALO NY SWINGING THROUGH.  THIS LEAVES A WEAK UPPER LEVEL FLOW
IN S/W RIDGING/ANTICYCLONE ALOFT FOR FAIR AMOUNT OF UPPER LEVEL
EVACUATION SUPPORTING LOW LEVEL WAVE TO AMPLIFY NEAR BURLINGTON
AND GENERALLY REDUCE THE NE OR E PROGRESSION OF THE WAVE/FRONTAL
ZONE...EFFECTIVELY REDUCING CELL MOTION VECTORS IN THE VICINITY. 
CIRA LAYERED TPW WV LOOP AND 00Z SOUNDINGS CONTINUE TO INDICATE A
VERY DEEPLY SATURATED ENVIRONMENT ACROSS NEW ENGLAND WITH TPW
VALUES AOA 1.5" WELL OVER 90TH PERCENTILE AND CONTINUE TO SUPPORT
EFFICIENT RAINFALL GENERATION FOR ANY CELLS THAT DO DEVELOP. 
RECENT TRENDS AND RAP ANALYSIS ALSO INDICATES A FORK/SPLIT IN THE
MST AXIS WITH ONE CHANNEL RESPONDING TO THE SURFACE WAVE BANKED
THROUGH THE GREEN MTS/N WHITES AND ALONG THE FRONTAL BOUNDARY
ALONG QUEBEC/MAINE BORDER; WITH A SECOND CORRIDOR EXTENDING FROM
SE NH ACROSS CENTRAL ME TO NEAR KMLT.  

THE WESTERN/SURFACE CORRIDOR HAS FLATTENING LAPSE RATES DUE TO THE
WEAKENING CONVECTION...HOWEVER THERE ARE SOME POCKETS OF ENHANCED
CONVECTION AS WELL AS WEAKER SHALLOWER CELLS THAT WILL REMAIN
EFFICIENT (IF JUST LOWER IN TOTAL VOLUME) THAT WILL ADVANCE SLOWLY
EAST WHILE CELLS LIFT NORTHEAST WITH SOME TRAINING POSSIBLE.  FF
THREAT HERE IS DRIVEN MAINLY BY ONGOING FLOODING CONDITIONS FROM
EARLIER CONVECTION AS WELL AS RUGGED TERRAIN AND NARROW RUNOFF
FLOW CHANNELS. 

FURTHER SE ACROSS DOWN EAST ME...HI-RES CAMS ALONG WITH SOME HINTS
IN SHORTWAVE IR/MST CONVERGENCE FIELDS SUGGEST INCREASED FORCING
WILL SUPPORT NEW CONVECTIVE DEVELOPMENT IN THE 05-08Z TIME FRAME
THAT MAY HAVE SOME ADDITIONAL 100-500 J/KG CAPES TO SUPPORT DEEPER
CONVECTION THAT WOULD BE CAPABLE OF RATES .75-1"/HR.  CELL MOTIONS
WILL BE NEARLY PARALLEL TO THE CONVERGENCE BAND FOR TRAINING
CELLS.  FF THREAT IS CONTINGENT ON THIS TRAINING AND MAGNITUDE OF
RAIN RATES WHICH REMAINS IN SOME QUESTION AT THIS TIME. 

GALLINA

ATTN...WFO...ALY...BTV...CAR...GYX...

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

LAT...LON   47586939 47536825 46496752 45356824 43936943 
            43367040 42857155 42747245 43027309 44017269 
            45087229 45407148 46467068 47097000