Prognostic Meteorological Discussion
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000
FXUS01 KWBC 202009
PMDSPD

SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
408 PM EDT SUN AUG 20 2017

VALID 00Z MON AUG 21 2017 - 00Z WED AUG 23 2017

...FLASH FLOODING AND SEVERE THUNDERSTORMS WILL BE POSSIBLE OVER
PORTIONS OF THE UPPER MISSISSIPPI VALLEY SUNDAY EVENING INTO
MONDAY...

...THE THREAT FOR LOCALLY HEAVY RAINFALL ACROSS THE SOUTHERN
ROCKIES WILL CONTINUE INTO MONDAY...

A COLD FRONT PRESSING OUT OF THE NORTH CENTRAL U.S. EARLY THIS
WEEK WILL SERVE AS FOCUS FOR SHOWERS AND THUNDERSTORMS WHILE IT
STALLS OVER PORTIONS OF UPPER MISSISSIPPI VALLEY SUNDAY EVENING
INTO MONDAY.  AN ABUNDANCE OF MOISTURE AND INSTABILITY ALONG THE
LINGERING BOUNDARY SHOULD HEIGHTEN THE RISK FOR FLASH FLOODING AND
SEVERE WEATHER WITHIN DEVELOPING CONVECTION, ESPECIALLY FROM
EASTERN NEBRASKA INTO IOWA AND NORTHERN MISSOURI.  MONDAY NIGHT
INTO TUESDAY, AN AMPLIFYING UPPER TROUGH SHOULD HELP PUSH THE
FRONT SOUTH AND EASTWARD, SHIFTING THE FOCUS FOR HEAVY RAIN AND
THUNDERSTORMS INTO THE UPPER GREAT LAKES AND MIDDLE MISSISSIPPI
VALLEY.

THE COMBINATION OF MONSOONAL MOISTURE AND IMPULSES OF ENERGY ALOFT
WILL KEEP HEAVY RAINFALL A THREAT OVER THE SOUTHERN ROCKIES, WITH
LOCATIONS ACROSS NEW MEXICO AND EXTREME WEST TEXAS EXPECTED TO SEE
THE GREATEST THREAT FOR ANY FLASH FLOODING OR LOCAL RUNOFF
CONCERNS.  FARTHER WEST, A RELATIVELY STAGNANT UPPER LOW CENTERED
OFF THE CALIFORNIA COAST SHOULD HELP FOSTER MAINLY SCATTERED TO
ISOLATED SHOWER ACTIVITY ACROSS PORTIONS OF CALIFORNIA AND THE
CENTRAL GREAT BASIN EARLY THIS WEEK.

ELSEWHERE ACROSS THE NATION, TEMPERATURES WILL BE ON THE RISE
AGAIN OVER THE NORTHWESTERN U.S. AS AN UPPER RIDGE AMPLIFIES OVER
THE REGION EARLY THIS WEEK.  SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE ACROSS THE SOUTHEAST AND ALONG THE CENTRAL GULF COAST
OVER THE NEXT FEW DAYS.  ALTHOUGH ACTIVITY SHOULD BE MAINLY
SCATTERED IN NATURE, AN AXIS OF ANOMALOUS MOISTURE AND A WEAKNESS
ALOFT PROGRESSING WESTWARD ACROSS FLORIDA AND INTO THE GULF OF
MEXICO COULD HELP FUEL AND FOCUS LOCALLY HEAVY RAINFALL.


GERHARDT


GRAPHICS AVAILABLE AT
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP
$$





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