Preliminary Forecasts
Issued by NWS

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000
FXUS02 KWNH 230512
PREEPD

PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1211 AM EST SUN NOV 23 2014

VALID 12Z WED NOV 26 2014 - 12Z SUN NOV 30 2014


...ANOTHER COLD OUTBREAK FOR THE EAST...
...POSSIBLE SNOW WEDNESDAY FOR THE MID ATLANTIC AND NORTHEAST...

RELIED ON THE 12Z/22 EUROPEAN CENTRE ENSEMBLE MEAN AS A SYNOPTIC
GUIDE THIS FORECAST PERIOD. THE ECENS MEAN HAS BEEN MARKED BY A
STEADY SHARPENING OF ITS DEPICTION OF THE FLOW ACROSS THE UNITED
STATES AT THE MEDIUM RANGE, WITH THE 12Z/22 VERSION INDICATING A
MODEST CHANCE OF ACCUMULATING SNOW FOR PARTS OF THE MID ATLANTIC
AND NORTHEAST ON WEDNESDAY--THE BUSY TRAVEL DAY BEFORE
THANKSGIVING. HOW FAR WEST A WAVE TRACKS AS IT EMERGES FROM THE
EASTERN GULF OF MEXICO OFF THE SOUTHEASTERN ATLANTIC COAST TUESDAY
NIGHT IS KEY TO WHETHER RAIN AND SNOW SPREAD INTO THE METROPOLITAN
CORRIDOR FROM WASHINGTON TO BOSTON--OR EVEN FARTHER INLAND TO
INCLUDE THE APPALACHIANS--WEDNESDAY AND WEDNESDAY NIGHT. A CLIPPER
SYSTEM DIVING INTO THE UPPER MIDWEST WEDNESDAY IS AN IMPORTANT
PIECE IN THE EASTERN PUZZLE, AS ITS TRAJECTORY AND THE ATLANTIC
ONES ARE ALMOST CERTAINLY LINKED BASED ON THE SPREAD OF OUTCOMES
SEEN AMONG THE VARIOUS OPERATIONAL MODELS AND INDIVIDUAL ENSEMBLE
MEMBERS. WHATEVER THE INTERACTION BETWEEN THE TWO SYSTEMS, ANOTHER
NOVEMBER ARCTIC OUTBREAK SEEMS DESTINED FOR THE UPPER MIDWEST AND
ACROSS THE GREAT LAKES.

THE WEST COAST RIDGE SHOULD GRADUALLY ERODE THROUGH THE
PERIOD--THOUGH ITS MEAN POSITION SEEMS ANCHORED. THE SLOW EROSION
SHOULD RESULT IN A SENSIBLE UPTICK IN PRECIPITATION FROM
CALIFORNIA TO WASHINGTON STATE, WITH THE WARM CONDITIONS AT THE
START OF THE PERIOD IN SOUTHERN CALIFORNIA GIVING WAY TO A
SEASONABLE COOLNESS BY NEXT WEEKEND.


CISCO

$$





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