Prognostic Meteorological Discussion
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000
FXUS01 KWBC 152101
PMDSPD

SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
400 PM EST FRI DEC 15 2017

VALID 00Z SAT DEC 16 2017 - 00Z MON DEC 18 2017


...HEAVY SNOW POSSIBLE OVER PORTIONS OF THE GREAT LAKES...

...WELL BELOW NORMAL TEMPERATURES FROM THE NORTHERN PLAINS TO THE
MID-ATLANTIC...

...UNSETTLED AND WET CONDITIONS EXPECTED TO PERSIST THE NEXT FEW
DAYS FOR THE NORTHWEST U.S....


UPPER LEVEL ENERGY SWEEPING THROUGH THE DEEP SOUTH TONIGHT AND
TOMORROW WILL KEEP SHOWERS IN THE FORECAST FROM THE LOWER
MISSISSIPPI VALLEY EASTWARD THROUGH THE SOUTHEAST. EMBEDDED
THUNDERSTORMS ARE POSSIBLE ALONG WITH MODERATE TO LOCALLY HEAVY
RAINFALL. TEMPERATURES ACROSS THE REGION WILL BE BELOW NORMAL
AGAIN ON THURSDAY, EVENTUALLY MODERATING TO NEAR NORMAL BY FRIDAY.

IN THE NORTHERN STREAM, A VIGOROUS COLD FRONT DROPPING SOUTHWARD
ACROSS THE MIDWEST TONIGHT WILL ALLOW FOR MAINLY LIGHT
ACCUMULATING SNOWFALL ACROSS PORTIONS OF THE UPPER GREAT LAKES
THIS EVENING AND INTO THURSDAY. FAVORABLE FLOW OVER THE STILL
RELATIVELY WARM LAKES HOWEVER COULD BRING SOME LAKE ENHANCED
SNOWS, ESPECIALLY ACROSS PARTS OF THE UPPER PENINSULA OF MICHIGAN
WHERE WINTER WEATHER ADVISORIES AND WINTER STORM WARNINGS ARE IN
EFFECT FOR UPWARDS OF 6 INCHES OF SNOW. THE REAL STORY WITH THIS
FRONT HOWEVER WILL BE THE MODIFIED ARCTIC AIRMASS BEING USHERED IN
BEHIND THE FRONT, INITIALLY ACROSS THE NORTHERN PLAINS, BUT
EVENTUALLY MOVING INTO THE OHIO VALLEY AND THE
MID-ATLANTIC/NORTHEAST BY THE END OF THE WORK WEEK. TEMPERATURES
WITHIN THIS AIRMASS WILL BRING AFTERNOON HIGHS ACROSS THESE
REGIONS DOWN AS MUCH AS 10 TO 20 DEGREES BELOW NORMAL. THIS COULD
MEAN DAY TIME TEMPERATURES STRUGGLING TO GET OUT OF THE TEENS ON
THURSDAY, ESPECIALLY ACROSS FAR NORTHERN NORTH DAKOTA AND
MINNESOTA.

FINALLY, OUT WEST, A FRONTAL SYSTEM MOVING INTO THE PACIFIC
NORTHWEST THIS AFTERNOON WILL KEEP WET WEATHER IN THE FORECAST
ACROSS MUCH OF THE NORTHWEST STATES AND INTO THE ROCKIES THROUGH
THE REST OF THE WEEK. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE FOR
COASTAL AREAS OF THE PACIFIC NORTHWEST AND NORTHERN CALIFORNIA,
WITH SNOW EXPECTED IN THE HIGHEST ELEVATIONS OF THE CASCADES AND
INTO THE INTERMOUNTAIN WEST/NORTHERN ROCKIES. ACROSS NORTHEAST
WASHINGTON AND INTO NORTHWEST MONTANA, SOME LIGHT FREEZING RAIN
MAY ALSO BE POSSIBLE IN SOME OF THE LOWER ELEVATIONS.


SANTORELLI

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





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