Graphic for MPD #0146

MESOSCALE PRECIPITATION DISCUSSION 0146
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
740 PM EDT MON MAY 14 2018

AREAS AFFECTED...MID ATLANTIC REGION

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

VALID 142339Z - 150300Z

SUMMARY...HEAVY RAINFALL FROM A FAST MOVING LINE OF THUNDERSTORMS
MOVE TO AREAS SOUTH OF THE WASHINGTON DC AREA AND EAST OF THE BLUE
RIDGE TOWARDS SOUTHEAST VA BY 0300Z.  THE AIRMASS AHEAD OF THE
STORMS WAS CHARACTERIZED BY PRECIPITABLE WATER VALUES APPROACHING
1.5 INCHES.  AS A RESULT...THE STORMS WILL CONTINUE TO BE CAPABLE
OF PRODUCING HEAVY RAINFALL AND LOCALIZED FLASH FLOODING.  THE
FAST FORWARD SPEED OF THE STORMS WILL WORKING AGAINST WIDESPREAD
COVERAGE OF FLOODING DESPITE INTENSE RAINFALL.

DISCUSSION...A LINE OF THUNDERSTORMS MOVING FROM THE WASHINGTON DC
METRO AREA AROUND 23Z WILL CONTINUE TO MOVE SOUTHEASTWARD QUICKLY.
 KLWX RADAR HAS SHOWN SEVERAL WELL DEFINED VORTICIES WITHIN THE
LINE OF STORMS.  THIS HAS RESULTED IN SOME AREAS GETTING ENHANCED
RAINFALL AMOUNTS ALONG AND NORTH OF THE VORT TRACK.  IN
ADDITION...THE STORMS ARE MOVING TOWARDS AN AIRMASS WHICH HAS
PRECIPITABLE WATER VALUES APPROACHING 1.5 INCHES...SOME 2
STANDARDIZED ANOMALIES ABOVE CLIMATOLOGY.  AS A RESULT...LOCALIZED
RAINFALL RATES OF OF 1 TO 2 INCHES PER HOUR SHOULD CONTINUE TO BE
REALIZED.  THE FAST FORWARD SPEED OF THE LINE OF THUNDERSTORMS
SHOULD LIMIT FLOODING FROM BECOME TOO WIDESPREAD.  IN
ADDITION...FLASH FLOOD GUIDANCE IS NEAR 2.5 INCHES PER HOUR.

THEREFORE...A NEAR-TERM FLASH FLOOD THREAT APPEARS TO PERSIST
BASED ON RECENT RADAR TRENDS.  BIGGEST CONCERN WILL BE WHERE THESE
HEAVIER RAINFALL RATES OVER URBANIZED AREAS.

BANN

ATTN...WFO...AKQ...LWX...PHI...RNK...

ATTN...RFC...MARFC...SERFC...

LAT...LON   38927649 38647625 38357637 37907646 37237634
            37147761 37187795 37537834 37737776 38457674
           


Last Updated: 740 PM EDT MON MAY 14 2018