MESOSCALE PRECIPITATION DISCUSSION 0387
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
310 PM EDT MON JUL 02 2018

AREAS AFFECTED...WV INTO WRN MD PANHANDLE...CNTRL/WRN PA...CNTRL
NY

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 021906Z - 030105Z

SUMMARY...LOCALIZED FLASH FLOODING FROM CENTRAL WEST VIRGINIA INTO
THE WESTERN HALF OF PENNSYLVANIA AND CENTRAL NEW YORK IS EXPECTED
THROUGH THE EARLY EVENING HOURS. MAXIMUM RAINFALL RATES OF 1.5 TO
2.5 IN/HR MAY ALLOW FOR A FEW PLACES TO PICK UP 2 TO 3+ INCHES.

DISCUSSION...REGIONAL RADAR IMAGERY AT 1845Z SHOWED SCATTERED
THUNDERSTORMS FROM THE OHIO VALLEY INTO WESTERN NEW YORK AND A
SECOND AXIS FROM EASTERN LAKE ONTARIO SOUTHWESTWARD INTO THE WEST
VIRGINIA PANHANDLE. THE STORMS WERE DEVELOPING IN THE VICINITY OF
A MID-LEVEL SHEAR AXIS EXTENDING FROM LAKES ERIE AND ONTARIO INTO
THE TENNESSEE VALLEY...AND ALONG THE ELEVATED TERRAIN OF THE
ALLEGHENY MOUNTAINS WITH ENHANCEMENTS NEAR MESOSCALE CIRCULATIONS
WHICH WERE OBSERVED ON WATER VAPOR AND VISIBLE IMAGERY AHEAD OF
THE SHEAR AXIS. THE ENVIRONMENT OUT AHEAD OF A SLOW MOVING COLD
FRONT HAS STANDARDIZED ANOMALIES OF PRECIPITABLE WATER IN THE 2-3
RANGE ALONG WITH 1500-2500 J/KG MLCAPE VIA THE 18Z SPC
MESOANALYSIS PAGE. WHILE A KEY MISSING INGREDIENT FOR A MORE
WIDESPREAD FLASH FLOOD THREAT IS A LACK OF BETTER SHEAR...SHORT
LIVED CELLS HAVE BEEN AND WILL BE CAPABLE OF PRODUCING BRIEF HEAVY
RAINFALL WITH RATES OF 1.5 TO 2.5 IN/HR AND STORM TOTAL OF 2 TO 3+
INCHES.

WHILE PINPOINTING ANY ONE SPECIFIC REGION FOR FLASH FLOODING IN
THIS SETUP IS DIFFICULT...IT APPEARS AN ELEVATED RISK FOR FLASH
FLOODING WILL DEVELOP BETWEEN THE TWO ONGOING AXES OF
THUNDERSTORMS WHERE SKIES ARE CLEAR. AS THE COLD FRONT CONTINUES
EASTWARD...CONVECTION IS EXPECTED TO TRANSLATE AND CONCURRENTLY
DEVELOP INTO CENTRAL WEST VIRGINIA...WESTERN PENNSYLVANIA AND
CENTRAL NEW YORK THROUGH 00Z. WHILE LOW LEVEL SHEAR IS SLIGHTLY
STRONGER INTO NEW YORK AND FARTHER SOUTH HAS THE MORE SUSCEPTIBLE
TERRAIN FOR FLASH FLOODING...ALL ACROSS THE REGION WILL SEE THE
POTENTIAL FOR SHORT TERM TRAINING...OUTFLOW MERGERS AND LOCALIZED
HEAVY RAIN WITH 2 TO 3+ INCHES POSSIBLE OVER A 1-2 HOUR PERIOD.

WHILE NO SINGLE MODEL SEEMS TO HAVE A SOLID HANDLE ON ONGOING
CONVECTION...PERHAPS THE 16-18Z RUNS OF THE HRRR WERE DOING THE
BEST AND WERE USED AS A PSEUDO GUIDE FOR THIS MPD.

OTTO

ATTN...WFO...BGM...BUF...CLE...CTP...LWX...PBZ...RLX...

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

LAT...LON   43437620 43437554 43127531 42707534 42027626
            41247708 39987800 38717896 38258025 38328133
            38988149 40448078 41308101 41888020 42627856
            42987773 43277693