Prognostic Meteorological Discussion
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000
FXUS01 KWBC 202029
PMDSPD

SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
429 PM EDT FRI OCT 20 2017

VALID 00Z SAT OCT 21 2017 - 00Z MON OCT 23 2017

...HEAVY SNOW POSSIBLE OVER THE NORTHERN CASCADES INTO PARTS OF
THE NORTHERN ROCKIES...

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

...HEAVY RAIN POSSIBLE OVER THE SOUTHERN PLAINS/LOWER MISSISSIPPI
VALLEY...

A FRONT OVER THE NORTHERN HIGH PLAINS EXTENDS ROUGHLY
SOUTHWESTWARD TO THE GREAT BASIN THAT WILL SLOWLY MOVE EASTWARD TO
THE UPPER GREAT LAKES/MIDDLE MISSISSIPPI VALLEY AND PARTS OF THE
SOUTHERN PLAINS BY SUNDAY.  OVERNIGHT FRIDAY, SHOWERS AND
THUNDERSTORMS WILL DEVELOP ALONG AND AHEAD OF THE BOUNDARY OVER
PARTS OF THE UPPER MISSISSIPPI VALLEY IN TO THE CENTRAL/SOUTHERN
PLAINS THAT WILL SLOWLY MOVE EASTWARD TO THE UPPER GREAT
LAKES/UPPER MISSISSIPPI VALLEY INTO THE MIDDLE/LOWER MISSISSIPPI
VALLEY AND PARTS OF THE SOUTHERN PLAINS BY SUNDAY MORNING.

IN ADDITION, MOISTURE FROM THE WESTERN GULF OF MEXICO WILL FLOW
NORTHWARD OVER THE SOUTHERN PLAINS/LOWER MISSISSIPPI VALLEY THAT
WILL PROTRUDE INTO THE UPPER MISSISSIPPI VALLEY/UPPER GREAT LAKES
THROUGH SUNDAY.  WEAK UPPER-LEVEL ENERGY OVER THE SOUTHERN PLAINS
WILL AID IN PRODUCING SHOWERS AND THUNDERSTORMS OVER PARTS OF THE
WESTERN/CENTRAL GULF COAST THROUGH SATURDAY AFTERNOON.

MEANWHILE, STRONG ONSHORE LOW-LEVEL FLOW WILL STREAM MOISTURE INTO
THE PACIFIC NORTHWEST THAT WILL AID IN PRODUCING RAIN OVER PARTS
OF THE PACIFIC NORTHWEST WITH SNOW OVER THE HIGHER ELEVATIONS OF
THE CASCADES THROUGH SATURDAY MORNING.  RAIN AND HIGHER ELEVATIONS
SNOW WILL DEVELOP OVER PARTS OF NORTHERN CALIFORNIA INTO THE
NORTHERN INTERMOUNTAIN REGION/NORTHERN ROCKIES INTO PARTS OF THE
GREAT BASIN AND CENTRAL ROCKIES THROUGH SATURDAY AFTERNOON.  ON
SATURDAY, THE SNOW LEVELS WILL RISE OVER THE WEST AS UPPER-LEVEL
RIDGING MOVES ONSHORE.  ADDITIONALLY, MOISTURE WILL SURGE ONSHORE
OVER THE PACIFIC NORTHWEST PRODUCING RAIN, HEAVY AT TIMES, OVER
THE NORTHWEST INTO THE NORTHERN INTERMOUNTAIN REGION/NORTHERN
ROCKIES SATURDAY AFTERNOON INTO SUNDAY.

ELSEWHERE, EASTERLY FLOW OFF THE ATLANTIC WILL AID IN PRODUCING
SHOWERS AND THUNDERSTORMS OVER SOUTHERN FLORIDA THROUGH SUNDAY
MORNING.


ZIEGENFELDER


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




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