Prognostic Meteorological Discussion
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FXUS01 KWBC 210748
PMDSPD

SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
348 AM EDT MON AUG 21 2017

VALID 12Z MON AUG 21 2017 - 12Z WED AUG 23 2017

...FLASH FLOODING AND SEVERE WEATHER WILL BE POSSIBLE FROM THE
UPPER MISSISSIPPI VALLEY TO NEW ENGLAND OVER THE NEXT FEW DAYS...

...HEAVY RAINFALL WILL CONTINUE ACROSS THE SOUTHERN ROCKIES
TODAY...


A FRONT, WHICH HAS SLOWED ACROSS THE UPPER MISSISSIPPI VALLEY AND
CENTRAL PLAINS, WILL ACT AS A FOCUS FOR SHOWERS AND THUNDERSTORMS
OVER THE NEXT FEW DAYS. AS IT STALLS ACROSS THE UPPER MISSISSIPPI
VALLEY AND CENTRAL PLAINS, HEAVY RAINFALL LEADING TO FLASH
FLOODING AND SEVERE WEATHER IN THESE REGIONS WILL BE POSSIBLE ON
MONDAY.   AS THE UPPER LEVEL TROUGH BEGINS TO AMPLIFY AND PUSH
EASTWARD OVERNIGHT MONDAY AND INTO TUESDAY, THIS WILL MOBILIZE THE
COLD FRONT TO PROGRESS SOUTH AND EAST--AS WILL THE CONVECTION.
THE THREAT OF FLASH FLOODING WILL SHIFT TO THE SOUTHERN PLAINS AND
NORTHWARD INTO NEW ENGLAND. A SLIGHT RISK OF SEVERE WEATHER WILL
ALSO BE POSSIBLE FOR NEW ENGLAND AND THE OHIO VALLEY.  BY
WEDNESDAY MORNING, THE FRONT WILL MOVE INTO COASTAL NEW ENGLAND
THROUGH THE TENNESSEE VALLEY. EXPECT LIGHTER PRECIPITATION FROM
NEW ENGLAND THROUGH EASTERN TENNESSEE WITH SHOWERS AND
THUNDERSTORMS BEGINNING TO INCREASE ACROSS THE SOUTHEAST.  PLEASE
VISIT THE STORM PREDICTION CENTER FOR MORE DETAILED INFORMATION ON
SEVERE WEATHER AND WPC`S EXCESSIVE RAINFALL ON DETAILS AREAS OF
FLASH FLOODING.

AN UPPER LEVEL DISTURBANCE IN COMBINATION WITH MONSOONAL MOISTURE
WILL GIVE WAY TO HEAVY RAINFALL IN THE SOUTHERN ROCKIES AND
EXTREME WESTERN TEXAS AREA.  THE HEAVY RAINFALL IS EXPECTED TO
CONTINUE THROUGH MONDAY MORNING AND LIGHTEN UP BY THE
AFTERNOON--ALTHOUGH LINGERING SHOWERS AND THUNDERSTORMS WILL BE
CONTINUE THROUGH THE END OF THE DAY.  FLASH FLOODING WILL BE
POSSIBLE ON MONDAY AND INTO TUESDAY AS SOME OF THESE THUNDERSTORMS
COULD PRODUCE HEAVY DOWNPOURS.  FARTHER WEST, A SLOW-MOVING UPPER
LOW OFF THE CALIFORNIA COAST SHOULD GIVE WAY TO SCATTERED TO
ISOLATED SHOWER ACTIVITY ACROSS PORTIONS OF CALIFORNIA AND THE
CENTRAL GREAT BASIN EARLY THIS WEEK. HEAVIEST RAINFALL CAN BE
EXPECTED IN THE SIERRA NEVADA MOUNTAIN RANGE.

ELSEWHERE, ISOLATED TO SCATTERED THUNDERSTORMS WILL BE POSSIBLE
ACROSS THE DESERT SOUTHWEST EACH AFTERNOON DUE TO MONSOONAL
MOISTURE AND DAYTIME HEATING.  IN ADDITION, TYPICAL AFTERNOON
THUNDERSTORMS WILL HAPPEN ALONG THE CENTRAL AND EASTERN GULF COAST
THROUGH THE SHORT TERM PERIOD.  AS AN INVERTED TROUGH PUSHES
EASTWARD TOWARD THE EAST COAST OF FLORIDA ON TUESDAY AND
WEDNESDAY, EXPECT AN INCREASE OF PRECIPITATION. EXPECT MUCH COOLER
TEMPERATURES BEHIND THE COLD FRONT AS IT SWEEPS EASTWARD.
MEANWHILE, WARMER THAN NORMAL TEMPERATURES WILL OCCUR IN THE
PACIFIC NORTHWEST AND NORTHERN ROCKIES.

REINHART





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