Small Craft Advisory 169, NWS Fairbanks, AK

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
359 PM AKDT THU NOV 1 2012

.DISCUSSION...
BOTH THE NAM AND GFS COMPUTER WEATHER FORECAST MODELS FORECAST LOW
PRESSURE ALOFT OVER THE BEAUFORT SEA TO SEND A SHORT WAVE FROM THE
WESTERN ALASKA ARCTIC SLOPE TO THE YUKON BORDER BY SATURDAY
AFTERNOON.

THE GFS FORECASTS A WEAKER SHORT WAVE ALOFT TO MOVE SOUTHWARD
OVER THE EASTERN ALASKAN NORTH SLOPE SATURDAY NIGHT THROUGH
SUNDAY. THIS SYSTEM IS NOT EXPECTED TO BRING VIGOROUS WINTER
WEATHER TO THE ALASKAN ARCTIC AS ITS PREDECESSOR HAS.

LOW PRESSURE ALOFT WILL REMAIN OVER THE EASTERN INTERIOR THROUGH
MONDAY. THE GFS MODEL FORECASTS LARGE HIGH PRESSURE ALOFT OVER
SIBERIA AND THE WESTERN BERING SEA TO BUILD OVER WESTERN ALASKA
MONDAY AND TUESDAY. OVERALL...STRONG NORTH FLOW FROM THE ARCTIC
WILL PREVAIL OVER WESTERN ALASKA FOR THE NEXT 5 DAYS.

THE PATTERN OVER THE EASTERN AND CENTRAL INTERIOR WILL BE
DIFFERENT. WEAK LOW PRESSURE WILL PREVAIL THERE THROUGH THE
WEEKEND. THIS CIRCULATION LEAVES THE EASTERN INTERIOR OPEN TO
INFLUXES OF MOISTURE FROM A LARGE LOW PRESSURE AREA OVER THE GULF
OF ALASKA...STARTING FRIDAY NIGHT AND THROUGH THE WEEKEND.
THEREFORE...THIS AFTERNOONS FORECASTS INCLUDE SNOW IN THE EASTERN
INTERIOR AND ESPECIALLY IN THE EASTERN ALASKA RANGE.

THE WEATHER FRONT NOW OVER THE WESTERN AND CENTRAL ALASKAN ARCTIC
COAST WILL MOVE SOUTHWARD OVER THE INTERIOR FRIDAY NIGHT AND
SATURDAY. IT WILL WEAKEN CONSIDERABLY ONCE IT IS SOUTH OF THE
BROOKS RANGE. NONETHELESS...BRISK NORTHEAST WINDS OVER HIGHLAND
SUMMITS ARE EXPECTED TO FOLLOW THE FRONT FRIDAY NIGHT THROUGH
SATURDAY NIGHT.

STRONG CIRCULATION ON THE NORTHWEST PERIMETER OF THE LARGE GULF OF
ALASKA LOW WILL REACH THE BERING SEA COAST OF NORTHERN ALASKA
FRIDAY AND DIMINISH SATURDAY NIGHT AS THE LOW WEAKENS.

FREEZE UP ON THE ARCTIC COASTAL WATERS IS RAPIDLY IN PROGRESS.
MUCH OF THE CHUKCHI SEA IS ALREADY ICE COVERED. BY MONDAY
/NOVEMBER 5/...THE AREA OF ICE FREE WATERS IN THE BEAUFORT SEA IS
EXPECTED TO BE ABOUT ONE HALF OF ITS PRESENT EXTENT. SHOREFAST ICE
WILL BE IN PLACE OVER ALL OF THE ALASKAN ARCTIC COAST FROM
DEMARCATION POINT TO CAPE LISBURNE.

TODAYS POLAR ORBITING SATELLITE IMAGERY SHOWS BLURRED AREAS OF
FAIRLY UNIFORM INFRARED TEMPERATURES OVER THE NORTH AND WESTERN
INTERIOR. THESE ARE ASSOCIATED WITH BRISK NORTHEAST WINDS ABOVE
THE BOUNDARY LAYER.

COASTAL HAZARD POTENTIAL DAYS 3 AND 4 /SUNDAY AND MONDAY/...NONE

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
HEAVY FREEZING SPRAY WARNING FOR PKZ200-PKZ210-PKZ220-PKZ225-
PKZ230-PKZ235-PKZ240-PKZ245.

SMALL CRAFT ADVISORY FOR PKZ200-PKZ210-PKZ225-PKZ235-PKZ240-
PKZ245.
&&

TF NOV 12