Prognostic Meteorological Discussion
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000
FXUS01 KWBC 302128
PMDSPD

SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
527 PM EDT THU OCT 30 2014

VALID 00Z FRI OCT 31 2014 - 00Z SUN NOV 02 2014

...HEAVY SNOW POSSIBLE FOR PORTIONS OF THE SOUTHERN AND CENTRAL
APPALACHIANS FRIDAY NIGHT AND SATURDAY...

...WELL BELOW-AVERAGE TEMPERATURES EXPECTED FOR MOST OF THE
CENTRAL AND EASTERN U.S...

...STRONG PACIFIC STORM SYSTEM TO BRING RAIN AND SNOW TO MUCH OF
THE WEST AND INTERMOUNTAIN WEST...


BOTH THE WESTERN AND EASTERN U.S. WILL SEE SIGNIFICANT WEATHER
DURING THE SHORT RANGE FORECAST PERIOD AS THE UPPER-LEVEL FLOW
ACROSS THE NATION BECOMES HIGHLY AMPLIFIED. A VIGOROUS UPPER-LEVEL
DISTURBANCE WILL DIVE SOUTHWARD ACROSS THE UPPER GREAT LAKES
TONIGHT AND INTO THE OHIO VALLEY ON FRIDAY. AT THE SURFACE, ONE
FRONTAL SYSTEM WILL CROSS THE GREAT LAKES AND OHIO VALLEY WHILE
ANOTHER DEVELOPS AND DEEPENS OFF THE NORTH CAROLINA COAST. A POLAR
HIGH PRESSURE WILL USHER A MUCH COLDER AIRMASS INTO THE CENTRAL
AND EASTERN U.S. BEHIND THE WESTERN OF THE TWO AFOREMENTIONED
SYSTEMS, WITH TEMPERATURES 10 TO 20 DEGREES BELOW AVERAGE IN SOME
AREAS. RAIN AND SNOW WILL BE POSSIBLE ACROSS THE GREAT LAKES ON
FRIDAY AS THE SYSTEM CROSSES THE AREA, WITH SNOW FOR THE OHIO
VALLEY. THE MORE SIGNIFICANT EVENT WILL BEGIN FRIDAY NIGHT INTO
EARLY SATURDAY, HOWEVER, AS THE ENERGY FROM THE TWO SYSTEMS BEGINS
TO COMBINE, AND COLDER AIR CHANGES RAIN OVER TO SNOW ACROSS MUCH
OF THE EASTERN OHIO VALLEY, AND CENTRAL AND SOUTHERN APPALACHIANS.
UPSLOPE FLOW ACROSS THE APPALACHIANS WITH NORTHWESTERLY FLOW MAY
ENHANCE SNOWFALL, AND HEAVY SNOW IS POSSIBLE. ADDITIONALLY, RAIN
AND SNOW ARE POSSIBLE ON SATURDAY ACROSS PORTIONS OF NORTHERN
INTERIOR NEW ENGLAND.

ANOTHER VIGOROUS LOW-PRESSURE SYSTEM WILL MOVE ONSHORE IN THE WEST
TONIGHT. WIDESPREAD PRECIPITATION IS EXPECTED ALONG AND IN THE
WAKE OF THE SURFACE FRONT. WHILE PRECIPITATION WILL BEGIN AS RAIN
AT ALL BUT THE HIGHEST ELEVATIONS OF THE WEST, SNOW LEVELS WILL
GRADUALLY LOWER AS THE FRONT MOVES INLAND AND THE UPPER-LEVEL
TROUGH CROSSES OVERHEAD, SO BY SATURDAY SNOW WILL BECOME MUCH MORE
COMMONPLACE ACROSS THE INTERMOUNTAIN WEST.

RYAN


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





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