MESOSCALE PRECIPITATION DISCUSSION 0151
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
758 PM EDT TUE JUN 24 2014
 
AREAS AFFECTED......NORTHEAST OH/NORTHWEST PA/WESTERN NY STATE... 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 242357Z - 250357Z
 
SUMMARY...CONVECTION ON THE NOSE OF A LOW LEVEL SOUTHWEST JET WILL
CROSS NORTHEAST OH INTO NORTHWEST PA AND WESTERN NY STATE INTO THE
LATE EVENING HOURS. THE CONVECTION WILL FOLLOW THE AXIS OF HIGH
MOISTURE CONTENT AIR AND RESIDUAL INSTABILITY TO POSE THE
POTENTIAL FOR FLASH FLOODING.

DISCUSSION...CONVECTION ON THE NOSE OF A 20 TO 30 KNOT LOW LEVEL
JET OVER NORTHWEST OH AT 0045Z SHOULD CONTINUE TO FOLLOW THE BEST
PWAT VALUES (NEAR 1.75 INCHES...OR ABOUT TWO STANDARD DEVIATIONS
ABOVE NORMAL) AND INSTABILITY ACROSS NORTHEAST OH INTO NORTHWEST
PA AND WESTERN NY STATE. THE CONVECTION IS BEING MAINTAINED BY
MUCAPE BETWEEN 1500 AND 2000 J/KG ACROSS NORTHERN AND CENTRAL
OH...AHEAD OF A COMPACT SHORT WAVE/MCV OVER EASTERN IN.

THE CONSENSUS OF HIGH RESOLUTION GUIDANCE PLACES A SWATH OF HEAVY
RAIN ALONG THE AXIS OF HIGHEST PWAT AHEAD OF THE SHORT/MCV. IN
FACT...THE LATEST ARW AND NAM CONEST SUGGEST AS MUCH AS 3-5 INCHES
OF RAIN IN SPOTS ALONG THIS AXIS. HOWEVER...THE MAJORITY OF
AVAILABLE HIGH RESOLUTION GUIDANCE SHOWS THE MUCAPE DROPPING BELOW
500 J/KG BY THE 04-05Z TIME FRAME.

BECAUSE OF THE UNCERTAINTY CONCERNING THE AVAILABILITY OF
INSTABILITY TO MAINTAIN THE CONVECTION PAST 03Z...THE THREAT LEVEL
FOR FLASH FLOODING IS NOT AS HIGH AS SOME OF THE HIGH RESOLUTION
GUIDANCE SUGGESTS. HOWEVER...THE THREAT SHOULD REMAIN IN PLACE
THROUGH ABOUT 05Z.

HAYES

ATTN...WFO...ALY...BGM...BUF...CTP...PBZ...CLE...

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

LAT...LON   41438258 42398047 43387812 43827552 43267479 41707716
            40808070 40478263 41108292 41438254 41438258