WPC Met Watch |
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Mesoscale Precipitation Discussion: #0185 (2015) |
(Issued at 547 PM EDT MON JUN 08 2015
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MPD Selection |
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MESOSCALE PRECIPITATION DISCUSSION 0185
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
547 PM EDT MON JUN 08 2015
AREAS AFFECTED...NRN MD INTO ERN PA...NWRN NJ AND SRN NY
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 082144Z - 090300Z
SUMMARY...SHORT TERM TRAINING OF CELLS WILL CONTINUE A THREAT FOR
FLASH FLOODING INTO THE LATE EVENING HOURS FROM NRN MARYLAND INTO
NRN NEW JERSEY AND SRN NEW YORK STATE. COVERAGE OF FLASH FLOODING
IS EXPECTED TO REMAIN SOMEWHAT SCATTERED AND THE THREAT WILL
LIKELY DIMINISH WITH LOSS OF DAYTIME HEATING.
DISCUSSION...RECENT RADAR TRENDS THROUGH 21Z DEPICTED AN AREA OF
EXPANDING CONVECTION ACROSS S-CNTRL PENNSYLVANIA WITHIN A REGION
THAT HAS RECEIVED GOOD SOLAR INSOLATION THROUGHOUT THE AFTERNOON.
MLCAPES WERE HIGHEST ACROSS NRN MARYLAND INTO SERN
PENNSYLVANIA...WITH ESTIMATED VALUES RANGING BETWEEN 750 AND 1500
J/KG. MOISTURE ACROSS THE THREAT AREA PER GPS PWS WAS ANOMALOUSLY
HIGH...BUT ONLY BETWEEN 1 TO 2 STANDARDIZED ANOMALIES ABOVE THE
MEAN. DESPITE THE SOMEWHAT MODEST MOISTURE THOUGH...DUAL POL HAS
ESTIMATES OF A QUICK 2-3 INCHES OVER CUMBERLAND...PERRY AND
DAUPHIN COUNTIES IN PENNSYLVANIA.
FLOW IS UNIDIRECTIONAL FROM THE SOUTHWEST AND AN INCREASE IN 850
MB WINDS OF 10 KTS IS ANTICIPATED NEAR 00Z AS FORECAST BY RECENT
RUNS OF THE RAP...WHICH SHOULD HELP TO FAVOR PERIODS OF TRAINING
HEAVY RAINFALL WITH HOURLY RATES BETWEEN 1-2 IN/HR. AN APPROACHING
UPPER JET STREAK OF 70-90 KTS ON THE LEE SIDE OF A PROGRESSIVE
UPPER TROUGH MOVING ACROSS THE GREAT LAKES REGION SHOULD HELP IN
AIDING ASCENT ACROSS THE REGION THROUGH 00Z. FLASH FLOODING HAS
THE GREATEST POTENTIAL ACROSS SRN PORTIONS OF THE THREAT AREA
WHERE CAPES ARE HIGHEST AND ABLE TO SUSTAIN HIGHER RAINFALL RATES.
HI-RES MODELS SHOW A MARGINAL SIGNAL FOR FLASH FLOODING BUT THERE
ARE SOME POCKETS OF FLASH FLOOD GUIDANCE ACROSS THE THREAT REGION
WHICH ARE ONLY 1 IN/HR. FLASH FLOODING WILL REMAIN A POSSIBILITY
HERE...BUT IT IS EXPECTED TO WANE WITH THE LOSS OF DAYTIME HEATING
THROUGH 03Z.
OTTO
ATTN...WFO...ALY...BGM...CTP...LWX...OKX...PHI...
ATTN...RFC...MARFC...NERFC...
LAT...LON 41857497 41637388 41057371 40287447 39417623
39227762 39947762 41097636
Last Updated: 547 PM EDT MON JUN 08 2015
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