Small Craft Advisory 94, NWS Fairbanks, AK

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
154 AM AKDT MON SEP 5 2011

.DISCUSSION...
MODELS IN DECENT AGREEMENT THROUGH AT LEAST 48 HOURS. A LARGE LOW
IN THE GULF OF ALASKA WILL DEEPEN TO NEAR 954 MB BY LATE MORNING
AND THEN WEAKEN AND MOVE TO NEAR KODIAK ISLAND AS A 962 MB LOW BY
LATE MORNING ON TUE.

AS THE UPPER LEVEL FLOW CONTINUES FROM THE EAST FOR THE EASTERN
PORTION OF NORTHERN ALASKA SOME PRECIPITATION MAY MAKE IT INTO THE
CENTRAL AND EASTERN INTERIOR BY TUE AFTERNOON AND THEN SPREAD TO
NEAR BETTLES BY TUE EVENING.

THE BIGGEST IMPACT FOR NORTHERN ALASKA WILL BE THE LOW LEVEL WINDS
FROM THE STRONG PRESSURE GRADIENT BEING DEVELOPED FROM THE LOW IN
THE GULF OF ALASKA AND HIGH PRESSURE OVER EASTERN RUSSIA. NORTH TO
NORTHEAST WINDS 20 TO 30 MPH OVER HIGHER TERRAIN IN THE CENTRAL
PORTION OF NORTHERN ALASKA WILL BE NORMAL THROUGH TUE AFTERNOON
WHEN THE LOW WEAKENS RAPIDLY AND CONTINUES TO MOVE WEST TO THE
WESTERN PORTION OF KODIAK ISLAND BY TUE NIGHT.

MARINE ADVISORIES AND WARNINGS HAVE BEEN ISSUED IN CONJUNCTION
WITH THIS STORM.

N THE MEDIUM RANGE...A DEEP LOW THAT DEVELOPS IN THE VCNTY OF
KODIAK ISLAND DURING THE SHORT TERM WILL BE RAPIDLY FILLING AT THE
START OF THE MEDIUM RANGE.  A DEEP TROUGH ALOFT WILL EXTEND ALONG
160W WITH LOW CENTERS ALOFT OVER THE ARCTIC OCEAN AND SOUTH OF THE
AK PENINSULA.  THE MODEL AND ENSEMBLE SPREAD INCREASE LATE IN THE
WEEK INTO NEXT WEEKEND.  THE MAIN CAUSE FOR THIS SPREAD IS A VERY
COMPLEX LOW IN SIBERIA THAT SLOWLY DRIFTS INTO THE BERING SEA.
GIVEN THE COMPLEX NATURE OF THIS LOW AND THE INTERACTION WITH
EX-TROPICAL SYSTEMS TALAS AND NORU THE PATTERN ACROSS MAINLAND AK
BECOMES INCREASINGLY UNCERTAIN. IT WOULD APPEAR MOST LIKELY THAT
THERE WILL BE A PERIOD OF WLY FLOW ALOFT LATE IN THE WEEK AS THE
TROUGH THAT EXTENDS INTO THE ARCTIC LIFTS OUT.  THIS MAY BE FOLLOWED
BY A BUILDING RIDGE ACROSS THE MAINLAND OUT AHEAD OF THE LOW COMPLEX
THAT MOVES INTO THE BERING SEA.   IF ALL THIS PANS OUT IT NAY LEAD
TO A PERIOD OF PLEASANT FALL WEATHER FOR MUCH OF THE INTERIOR WITH
MOST OF THE UNSETTLED WEATHER ALONG THE WEST COAST.

COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE

&&

.FIRE WEATHER...NONE.

&&

.HYDROLOGY...NONE.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY FOR AKZ207-AKZ213.

SMALL CRAFT ADVISORY FOR PKZ200-PKZ215-PKZ230.

GALE WARNING FOR PKZ200-PKZ210-PKZ220-PKZ225.
&&

CF SEP 11