Prognostic Meteorological Discussion
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FXUS01 KWBC 180758
PMDSPD

SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
257 AM EST MON DEC 18 2017

VALID 12Z MON DEC 18 2017 - 12Z WED DEC 20 2017

...HEAVY SNOWS LIKELY ACROSS THE CASCADES AND THE NORTHERN ROCKIES
ON TUESDAY...

...HEAVY RAINFALL AND FLASH FLOODING POSSIBLE ACROSS PORTIONS OF
THE LOWER MISSISSIPPI VALLEY INTO THE TENNESSEE VALLEY ON
TUESDAY...


THE WORK WEEK ACROSS THE PACIFIC NORTHWEST STARTS OUT WITH SOME
GENERAL RAIN AND MOUNTAIN SNOWS ACROSS THE HIGHER PEAKS OF THE
WASHINGTON CASCADES AND THE NORTHERN ROCKIES ON MONDAY. BY TUESDAY
HOWEVER, A COLD FRONT MOVING INLAND WILL BRING INCREASED MOISTURE
TO MUCH OF THE NORTHWEST. EXPECT HEAVY RAINFALL ALONG THE
WASHINGTON, OREGON, AND NORTHERN CALIFORNIA COASTS, WITH HEAVY
SNOWFALL IN THE MOUNTAINS. FOR MUCH OF THE CASCADES RANGE AND THE
NORTHERN ROCKIES, UPWARDS OF A FOOT, MAYBE 2 FEET, OF SNOW IS
POSSIBLE.

MOISTURE STREAMING NORTHWARD FROM THE GULF OF MEXICO WILL KEEP
SHOWERS AND THUNDERSTORMS IN THE FORECAST ACROSS THE SOUTHERN
PLAINS AND THE GULF COAST STATES THE NEXT COUPLE OF DAYS. HEAVY
RAINFALL IS EXPECTED TO DEVELOP ACROSS PORTIONS OF THE LOWER
MISSISSIPPI VALLEY AND INTO THE TENNESSEE VALLEY ON TUESDAY AS A
WARM FRONT LIFTS NORTHWARD INTO THE REGION AND A SURFACE LOW
DEVELOPS ACROSS TEXAS. THE HEAVIEST RAINFALL SHOULD FOCUS ALONG
THE BOUNDARY FROM THE ARKLATEX REGION INTO THE TENNESSEE VALLEY
WHERE AS MUCH AS 3 TO 4 INCHES OF RAIN MAY BE POSSIBLE ON TUESDAY
AND INTO EARLY WEDNESDAY. WPC IS HIGHLIGHTING A SLIGHT RISK FOR
FLASH FLOODING ACROSS THIS REGION AS WELL.

ELSEWHERE, EXPECT MAINLY LIGHT RAIN OR SNOW SHOWERS ACROSS THE
NORTHEAST TODAY AS A WARM FRONT LIFTS THROUGH. FARTHER WEST, A
COLD FRONT MOVING ACROSS THE UPPER GREAT LAKES WILL KEEP SNOW IN
THE FORECAST ON MONDAY, WITH MORE RAIN SPREADING INTO THE
NORTHEAST ON TUESDAY, EVENTUALLY CHANGING OVER TO SNOW AS COLDER
AIR FILTERS IN BEHIND THE COLD FRONT.


SANTORELLI

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





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