Preliminary Forecasts
Issued by NWS

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FXUS02 KWNH 300538
PREEPD

PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
137 AM EDT SAT AUG 30 2014

VALID 12Z TUE SEP 02 2014 - 12Z SAT SEP 06 2014

...OVERVIEW...

SUBTROPICAL RIDGING IS FORECAST TO EXPAND OVER THE SOUTHERN AND
EASTERN STATES NEXT WEEK AS THE NORTHERN STREAM REMAINS ACTIVE
ACROSS THE US/CANADIAN BORDER. ENERGY CURRENTLY CRUISING THROUGH
THE GULF OF ALASKA WILL SWING THROUGH THE GREAT LAKES TUE/D3 AND
THE NORTHEAST WED/D4 BEFORE HEIGHTS BUILD IN ITS WAKE. MUCH
FARTHER UPSTREAM... ENERGY CURRENTLY IN THE BERING SEA WILL SWING
THROUGH THE GULF OF ALASKA AND THEN INTO THE PAC NW WED/D4 BEFORE
SHEARING OFF TO THE EAST WHILE TRAILING ENERGY HELPS MAINTAIN
LINGERING TROUGHING ALONG THE WEST COAST.

...GUIDANCE PREFERENCES...

THE MODELS/ENSEMBLES ARE IN GENERALLY GOOD AGREEMENT OVERALL...
BUT SMALL TIMING DIFFERENCES ALOFT TRANSLATE TO MUCH MORE
NOTICEABLE DIFFERENCES AT THE SURFACE. THE RECENT DETERMINISTIC
RUNS HAVE BOUNCED AROUND THE MORE STEADY ENSEMBLE MEANS AND HAVE
AGAIN FAVORED THEIR GOOD CONSENSUS. USED A BLEND OF THE 18Z GEFS
AND 12Z NAEFS/ECENS MEANS THROUGHOUT THE FORECAST WITH ADDED
DETAILS FROM THE 12Z ECMWF RATHER THAN THE SLIGHTLY QUICKER 12-18Z
GFS RUNS /IN THE HIGH PLAINS RIGHT FROM TUE/D3/.


..SENSIBLE WEATHER HIGHLIGHTS...

DESPITE THE FRONTAL PASSAGE IN THE NORTHEAST AND MID-ATLANTIC
WED/D4... TEMPERATURES WILL AVERAGE ABOVE NORMAL THROUGHOUT THE
PERIOD. THIS WILL EXTEND SOUTHWESTWARD TOWARD THE SOUTHERN PLAINS
THANKS TO THE EXPANSIVE UPPER RIDGING. TROUGHING IN THE NORTHWEST
WILL FAVOR BELOW AVERAGE TEMPERATURES. PRECIPITATION SHOULD FOCUS
IN THE CONFLUENCE ZONE BETWEEN SOUTHEASTERN RIDGING AND
NORTHWESTERN TROUGHING... I.E.... FROM THE GREAT LAKES AND
NORTHEAST /EARLY IN THE PERIOD/ AND THEN FROM THE HIGH PLAINS TO
THE UPPER MIDWEST LATER IN THE FORECAST. MID-LEVEL WAVE MOVING
WESTWARD THROUGH THE BAHAMAS AND FLORIDA WILL INCREASE THE CHANCE
FOR SHOWERS/STORMS LATER THIS WEEK.


FRACASSO

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