Prognostic Meteorological Discussion
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090
FXUS01 KWBC 220709
PMDSPD

SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
308 AM EDT SAT JUL 22 2017

VALID 12Z SAT JUL 22 2017 - 12Z MON JUL 24 2017

...FLASH FLOODING AND SEVERE WEATHER WILL BE POSSIBLE OVER
PORTIONS OF THE OHIO VALLEY AND MID-ATLANTIC STATES THIS WEEKEND...

...ANOTHER DAY OF DANGEROUS HEAT IS EXPECTED FROM THE CENTRAL
PLAINS AND MIDDLE MISSISSIPPI VALLEY TO THE MID-ATLANTIC COAST ON
SATURDAY...

...MONSOONAL MOISTURE WILL KEEP LOCALIZED FLASH FLOODING A THREAT
FROM THE SOUTHWEST TO THE SOUTHERN AND CENTRAL ROCKIES OVER THE
NEXT FEW DAYS...

A WAVY FRONTAL BOUNDARY STRETCHING FROM THE CENTRAL PLAINS TO THE
MID-ATLANTIC COAST EARLY SATURDAY WILL CONTINUE TO SERVE AS A
FOCUS FOR SHOWERS AND THUNDERSTORMS WHILE IT GRADUALLY SINKS
SOUTHEASTWARD THIS WEEKEND.  AN ABUNDANCE OF MOISTURE AND
INSTABILITY ALONG AND SOUTH OF THE BOUNDARY COULD LEAD TO HEAVY
DOWNPOURS AND SEVERE WEATHER WITHIN DEVELOPING CONVECTION,
ESPECIALLY FOR LOCATIONS ACROSS THE OHIO VALLEY AND NORTHERN
MID-ATLANTIC STATES ON SATURDAY.  STRONG TO SEVERE STORMS WILL
ALSO BE POSSIBLE FARTHER NORTH OVER THE UPPER MISSISSIPPI VALLEY
AND GREAT LAKES AS AMPLIFYING SHORTWAVE ENERGY PROGRESSES FROM THE
NORTHERN PLAINS TO INTERIOR NEW ENGLAND THIS WEEKEND.

HOT AND HUMID CONDITIONS WILL PERSIST FOR LOCATIONS SOUTH OF THE
WAVY FRONTAL BOUNDARY STRETCHING FROM THE CENTRAL PLAINS TO THE
MID-ATLANTIC COAST.  WIDESPREAD EXCESSIVE HEAT WARNINGS AND HEAT
ADVISORIES REMAIN IN EFFECT FOR MUCH OF THE CENTRAL TO SOUTHERN
PLAINS, MIDDLE TO LOWER MISSISSIPPI VALLEY, AND SOUTHERN
MID-ATLANTIC STATES, WHERE THE DANGEROUS COMBINATION OF HIGH
TEMPERATURES AND DEW POINTS WILL LEAD TO TRIPLE DIGIT HEAT INDEX
VALUES ON SATURDAY.  LOCATIONS ACROSS KANSAS AND MISSOURI SHOULD
BEGIN TO SEE RELIEF FROM THE HEAT AS THE WAVY FRONTAL BOUNDARY
SINKS THROUGH THE REGION SATURDAY NIGHT, BUT ELSEWHERE, THE
DANGEROUS HEAT WILL PERSIST INTO SUNDAY.

WEAK IMPULSES OF ENERGY ALOFT COMBINED WITH MONSOONAL MOISTURE
SHOULD HELP TRIGGER AND FUEL SCATTERED CONVECTION OVER THE
SOUTHWEST AND SOUTHERN TO CENTRAL ROCKIES SATURDAY AND SUNDAY
AFTERNOON AND EVENING.  LOCALIZED FLASH FLOODING WILL BE POSSIBLE
GIVEN THE ANOMALOUS MOISTURE IN PLACE ACROSS THE REGION.


GERHARDT


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





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