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000
FXUS01 KWBC 192058
PMDSPD

SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
457 PM EDT WED JUN 19 2013

VALID 00Z THU JUN 20 2013 - 00Z SAT JUN 22 2013

...DEEP UPPER LEVEL LOW WILL BRING UNSEASONABLY WET CONDITIONS
FROM THE GREAT BASIN TO THE NORTHERN PLAINS...

...SHOWERS AND THUNDERSTORMS WILL CONTINUE ACROSS THE SOUTHEAST
AND SOUTHERN ATLANTIC STATES...

A DEEP UPPER LEVEL LOW HAS MOVED INLAND FROM THE PACIFIC NORTHWEST
AND CONTINUES TO BRING UNSETTLED CONDITIONS ACROSS THE NORTHERN
GREAT BASIN.  THIS UPPER LEVEL LOW IS SLOWLY PROGRESSING EASTWARD
TOWARDS THE NORTHERN PLAINS; IN FACT, IT DOES NOT EXIT THE
NORTHERN ROCKIES UNTIL AFTER THE SHORT RANGE PERIOD. THE PLACEMENT
OF ALREADY UNSTABLE AIR COMBINED WITH ENOUGH LIFT AND ANOMALOUS
SUPPLY OF MOISTURE, SHOWERS AND THUNDERSTORMS WILL BE TRIGGERED
ALONG THE MOUNTAINS AND EVENTUALLY SPREAD EASTWARD INTO MONTANA
AND THE DAKOTAS BY EARLY THURSDAY MORNING. THE HEAVIEST RAINFALL,
ALONG WITH THE THREAT OF SEVERE WEATHER, WILL CONCENTRATE ALONG
THE U.S.-CANADA BORDER IN IDAHO AND MONTANA.  AS THE SURFACE
FRONTAL BOUNDARY ADVANCES INTO THE NORTHERN PLAINS BY THURSDAY
MORNING, MOST OF THE CONVECTION WILL TAPER OFF ACROSS THE NORTHERN
ROCKIES AND SURROUNDING REGIONS.  HOWEVER, DUE TO THE SLOW MOVING
NATURE OF THE UPPER LEVEL LOW, SHOWERS WITH PERIODS OF MODERATE
RAINFALL WILL LINGER ACROSS THE PACIFIC NORTHWEST AND PORTIONS OF
THE GREAT BASIN THROUGH FRIDAY.

THE GULF COAST REGION ALONG WITH SOUTHEASTERN ATLANTIC STATES WILL
CONTINUE WITH ITS ROUNDS OF SHOWERS AND THUNDERSTORMS.  A COLD
FRONT IS SLOWLY DIPPING SOUTHWARD ACROSS THE SOUTHEAST. THIS
BOUNDARY WILL STALL OUT AND REMAIN ALONG THE GULF COAST AND OFF
THE COAST OF THE CAROLINAS THROUGH FRIDAY EVENING.  SOUTHERLY
WINDS WILL BESTOW THIS REGION WITH COPIOUS AMOUNTS OF WARM GULF
MOISTURE AND THE AFOREMENTIONED BOUNDARY WILL PROVIDE FOCUS FOR
SCATTERED THUNDERSTORMS AND SHOWERS.  A SURFACE LOW WILL REMAIN
ADJACENT TO THE CAROLINA COAST AND ALLOW SOME OF THE HEAVIER
ACTIVITY TO CONCENTRATE AROUND THAT REGION. BY THURSDAY NIGHT AND
INTO FRIDAY MORNING, THE MAJORITY OF THE CONVECTION WILL SUBSIDE.
WITH THAT SAID, DON`T EXPECT ALL OF THE CONVECTION TO SUBSIDE AS
THE BOUNDARY WILL STICK AROUND FOR THE BEGINNING OF THE WEEKEND.



FANNING


GRAPHICS AVAILABLE AT WWW.WPC.NCEP.NOAA.GOV
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