Prognostic Meteorological Discussion
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000
FXUS01 KWBC 211950
PMDSPD

SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
349 PM EDT FRI JUL 21 2017

VALID 00Z SAT JUL 22 2017 - 00Z MON JUL 24 2017

...THE HOT AND HUMID CONDITIONS PLAGUING THE EASTERN U.S. FROM THE
CENTRAL PLAINS TO THE MID-ATLANTIC REGION WILL CONTINUE INTO THE
WEEKEND...

...HEAVY RAIN AND SEVERE WEATHER WILL BE POSSIBLE IN THE UPPER
MIDWEST, GREAT LAKES, AND OHIO VALLEY AND WILL SHIFT TO THE
NORTHERN MID-ATLANTIC REGION BY THE WEEKEND...

...MONSOONAL MOISTURE MOVING INTO THE SOUTHWEST IN ADDITION TO THE
CENTRAL AND SOUTHERN ROCKIES WILL BRING A THREAT OF LOCALIZED
FLASH FLOODING...

THE UPPER LEVEL RIDGE THAT SPANS FROM THE CENTRAL PLAINS TO THE
MID-ATLANTIC STATES WILL CONTINUE TO MAINTAIN THE HOT AND HUMID
CONDITIONS ACROSS THESE REGIONS THROUGH FRIDAY AND SATURDAY.  MANY
STATES IN THE PLAINS, MIDDLE MISSISSIPPI VALLEY, AND EVEN THE
SOUTHEAST HAVE EXCESSIVE HEAT WARNINGS AND HEAT ADVISORIES; HIGH
TEMPERATURES ARE EXPECTED TO REACH NEAR OR AT THE CENTURY MARK AND
HEAT INDICES CLIMBING TO 110 DEGREES OR HIGHER.  THE MID-ATLANTIC
REGION AND A LARGE PORTION OF NORTH CAROLINA ALSO HAVE HEAT
ADVISORIES IN ADDITION TO A SMALL AREA OF EXCESSIVE HEAT WARNINGS.
ON SATURDAY, A COLD FRONT WILL PUSH SOUTHWARD ACROSS THE PLAINS
AND MISSISSIPPI VALLEY AND WILL BRING RELIEF FROM THE HEAT BY
SUNDAY ACROSS THESE AREAS. HIGH TEMPERATURES ARE EXPECTED TO COOL
DOWN AND BE CLOSER TO SEASONAL AVERAGE.  HOWEVER, HOT AND HUMID
CONDITIONS WILL STILL CONTINUE FOR THE MID-ATLANTIC AND THE
CAROLINAS ON SUNDAY AS THE FRONT WILL NOT MOVE THROUGH THESE AREAS
UNTIL EARLY NEXT WEEK.

A WAVY FRONTAL BOUNDARY THAT WILL STRETCH FROM THE UPPER MIDWEST
AND GREAT LAKES TO THE OHIO VALLEY AND MID-ATLANTIC REGION WILL BE
THE DOMINANT FEATURE THAT HELP FOCUS SHOWERS AND THUNDERSTORMS
ALONG IT THROUGH THE WEEKEND.  WITH PLENTY OF INSTABILITY AND
MOISTURE PRESENT, CONVECTION LEADING TO FLASH FLOODING AND SEVERE
WEATHER WILL BE POSSIBLE IN THESE REGIONS. TONIGHT AND INTO EARLY
SATURDAY MORNING, MOST OF THE CONVECTION IS EXPECTED TO OCCUR IN
THE UPPER MIDWEST/UPPER GREAT LAKES.  THROUGHOUT MOST OF SATURDAY,
SHOWERS AND THUNDERSTORMS WILL MOVE ALONG THE BOUNDARY ACROSS THE
OHIO VALLEY AND LOWER GREAT LAKES.  BY SATURDAY NIGHT AND INTO
SUNDAY, THE FOCUS OF HEAVY RAIN AND SEVERE WEATHER SHIFTS TO THE
NORTHERN MID-ATLANTIC.  SEE WPC`S EXCESSIVE RAINFALL OUTLOOK AND
SPC`S CONVECTIVE OUTLOOK FOR SPECIFIC INFORMATION ON FLASH
FLOODING AND SEVERE WEATHER, RESPECTIVELY.

MONSOONAL MOISTURE COMBINING WITH WEAK ENERGY ALOFT WILL FIRE OFF
SHOWERS AND THUNDERSTORMS ACROSS THE SOUTHWEST AND THE
CENTRAL/SOUTHERN ROCKIES ON FRIDAY THROUGH SUNDAY.  MOST OF THIS
ACTIVITY CAN BE EXPECTED IN THE LATE AFTERNOON AND EARLY EVENING
AS DAYTIME HEATING WILL HELP TRIGGER THE CONVECTION.  SOME OF
THESE THUNDERSTORMS COULD PRODUCE HEAVY DOWNPOURS AND LEAD TO
LOCALIZED FLASH FLOODING.

DAYTIME HEATING WILL ALSO LEAD TO AFTERNOON SHOWERS AND
THUNDERSTORMS ACROSS THE GULF COAST STATES.  MEANWHILE, A FRONT
APPROACHING BRITISH COLUMBIA BOUGHT BRING LIGHT PRECIPITATION TO
NORTHWESTERN WASHINGTON ON SATURDAY.


REINHART


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





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