Prognostic Meteorological Discussion
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FXUS01 KWBC 212046
PMDSPD

SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
345 PM EST TUE NOV 21 2017

VALID 00Z WED NOV 22 2017 - 00Z FRI NOV 24 2017

...HEAVY RAIN POSSIBLE OVER THE PACIFIC NORTHWEST...

...RAIN CHANGING TO SNOW OVER PARTS OF THE LOWER GREAT LAKES...

A FRONT EXTENDING FROM THE LOWER GREAT LAKES ROUGHLY SOUTHWESTWARD
TO THE LOWER MISSISSIPPI VALLEY/SOUTHERN PLAINS WILL MOVE EAST AND
SOUTHWARD TO OFF THE EASTERN SEABOARD AND THE GULF COAST BY
WEDNESDAY.  AN AREA OF RAIN AND SNOW OVER PARTS OF THE GREAT LAKES
WILL MOVE EASTWARD INTO NORTHERN NEW ENGLAND BY WEDNESDAY EVENING
AND INTO CANADA BY LATE WEDNESDAY NIGHT.  IN THE WAKE OF THE
FRONT, LAKE EFFECT SNOW WILL DEVELOP FOR A SHORT TIME OVER PARTS
OF THE UPPER GREAT LAKES ON TUESDAY EVENING, ENDING BY WEDNESDAY
AFTERNOON.

MEANWHILE, AREAS OF DISORGANIZED UPPER-LEVEL ENERGY OVER THE
SOUTHEAST AND THE SOUTHERN PLAINS WILL AID IN PRODUCING SHOWERS
AND THUNDERSTORMS OVER PARTS OF THE WESTERN/EASTERN GULF COAST AND
PARTS OF THE SOUTHEAST THROUGH WEDNESDAY MORNING.  THE FIRST
BUNDLE OF ENERGY WILL MOVE OFF THE SOUTHEAST COAST OVERNIGHT
TUESDAY INDUCING AN AREA OF LOW PRESSURE OFF THE CAROLINA COAST
JUST AHEAD OF THE COLD FRONT.  THE LOW WILL BECOME A WAVE OF LOW
PRESSURE ALONG THE FRONT OVER THE WESTERN ATLANTIC THAT WILL MOVE
NORTHEASTWARD INTO THE CANADIAN MARITIMES OVERNIGHT WEDNESDAY.
OVERNIGHT TUESDAY, THE ENERGY WILL DEVELOP RAIN OVER PARTS OF THE
CAROLINAS INTO THE MID-ATLANTIC THAT WILL MOVE NORTHWARD INTO
SOUTHERN NEW ENGLAND BY WEDNESDAY MORNING AND INTO NORTHERN NEW
ENGLAND BY WEDNESDAY AFTERNOON.  THE RAIN WILL MOVE OFF THE NEW
ENGLAND COAST BY WEDNESDAY EVENING.  THE SECOND ARE OF UPPER-LEVEL
ENERGY WILL MOVE TO THE EASTERN GULF COAST AND, LIKEWISE, DEVELOP
A WAVE OF LOW PRESSURE ALONG THE BOUNDARY OVER THE EASTERN GULF OF
MEXICO OVERNIGHT WEDNESDAY INTO THURSDAY.  THE ENERGY WILL PRODUCE
SHOWERS AND THUNDERSTORMS OVER PARTS OF FLORIDA WEDNESDAY EVENING
INTO THURSDAY, THANKSGIVING.

ELSEWHERE, A PLUME OF MOISTURE FROM THE PACIFIC WILL STREAM INTO
THE PACIFIC NORTHWEST THAT WILL CONTINUE UNTIL THURSDSAY,
THANKSGIVING, AS THE AXIS OF MOISTURE MOVES SOUTHWARD INTO
NORTHERN CALIFORNIA ALSO ON THANKSGIVING.  THE MOISTURE WILL AID
IN PRODUCING RAIN OVER PARTS OF THE PACIFIC NORTHWEST EASTWARD
INTO PARTS OF THE NORTHERN ROCKIES THROUGH THURSDAY, THANKSGIVING.
 IN ADDITION, RAIN WILL MOVE INTO PARTS OF NORTHERN CALIFORNIA
COAST OVERNIGHT WEDNESDAY INTO THANKSGIVING.  FURTHERNMORE, A FAST
MOVING AREA OF LOW PRESSURE OVER THE NORTHERN HIGH PLAINS
WEDNESDAY MORNING, WILL MOVE EASTWARD TO THE UPPER GREAT LAKES BY
THANKSGIVING MORNING, THURSDAY.  AN AREA OF LIGHT SNOW WILL
DEVELOP OVER PARTS OF THE UPPER MISSISSIPPI VALLEY/NORTHERN PLAINS
ON WEDNESDAY AFTERNOON THAT WILL MOVE TO THE UPPER GREAT LAKES BY
THURSDAY MORNING, THANKSGIVING.


ZIEGENFELDER


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