Area Forecast Discussion
Issued by NWS Fairbanks, AK

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FXAK69 PAFG 292243
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
243 PM AKDT SAT AUG 29 2015

.DISCUSSION...
MAIN CONCERNS ACROSS NORTHERN AK INCLUDE PRECIP CHANCES...LIGHT
SNOW ACCUMULATIONS AT HIGHER ELEVATIONS OF THE BROOKS RANGE AND
THE NORTH SLOPES OF THE ALASKA RANGE...AND HIGH SURF ON THE
NORTHERN SEWARD COAST NEAR SHISHMAREF.

OVERALL...WEATHER PATTERN LOOKS TO BECOME MORE QUIET COMPARED TO
THE LAST FEW DAYS. DETERMINISTIC GUIDANCE ARE IN GOOD AGREEMENT
FOR THE MOST PART WITH THE LARGE SCALE PATTERN OUT TO ABOUT
54-HRS. SEEN ARE DIFFERENCES IN AMPLITUDE REGARDING THE MID-LEVEL
RIDGE THAT WILL BE BUILDING OVER THE NORTHEAST BERING SEA MON
ONWARD...AND PHASE OF SHORT WAVE TROUGHS ASSOCIATED WITH THE
LONGWAVE TROUGH AS IT MOVES TO SE AK/YUKON TERRITORY FROM
MAINLAND AK.

.ALOFT...
A LONGWAVE TROUGH CURRENTLY POSITIONED OVER MAINLAND AK STRETCHES
TO THE ALASKA PANHANDLE AND VANCOUVER ISLAND WITH A COLD LOW
NEAR BARROW. A SHORTWAVE TROUGHS NEAR CHUKCHI SEA COAST AND
ANOTHER NEAR THE KUSKOKWIM DELTA WILL ROTATE AND DROP SOUTHWARD
OVERNIGHT-TOMORROW. THE LOW ALOFT WILL THEN DROP SOUTH BECOMING
AN OPEN WAVE EXTENDING NORTH ACROSS THE ARCTIC AS A BROAD LOW
DEVELOPS IN THE EASTARN GULF OF ALASKA BY MON. MEANWHILE...RIDGE
WILL BUILD OVER THE CENTRAL BERING SEA FROM THE NORTH PACIFIC AND
MOVE INTO THE NORTHEAST BERING BY MON. THE NORTH PACIFIC RIDGE
WILL CONTINUE TO BUILD AND MOVE EASTWARD ACROSS MAINLAND
ALASKA...MOVING TO SOUTH CENTRAL AK BY WED AS THE AFOREMENTIONED
BROAD LOW ALOFT WEAKENS AND MOVES EAST TO BRITISH COLUMBIA AND THE
NORTHWEST TERRITORIES.

.SURFACE...
A 992 MB LOW BY BARROW WILL DRIFT SOUTH AND WEAKEN OVERNIGHT INTO
A TROUGH OVER THE WESTERN ARCTIC COAST EXTENDING FROM A COMPLEX
LOW OVER THE GULF OF ALASKA. A 1023 MB HIGH OVER NORTHEAST RUSSIA
AND ACROSS THE NORTH CENTRAL BERING SEA WILL MOVE SOUTH AND EAST
TO THE EASTERN BERING SEA BY SUN. HIGH PRESSURE WILL THEN MOVE AND
PREVAIL OVER THE WEST COAST...AND WESTERN AND CENTRAL ARCTIC
COAST...AND CENTRAL INTERIOR MON. MEANWHILE...LOW PRESSURE WILL
THEN DEVELOP FROM THE MACKENZIE DELTA NORTHWEST INTO THE EASTERN
BEAUFORT SEA SUN INTO MON.

A 35-40 KT LOW-LEVEL JET STREAM...SEEN ALOFT AT 850 MB...WILL
ROTATE AND TAKE AIM THROUGH THE BERING STRAIT-NORTON SOUND-YUKON
DELTA OVERNIGHT INTO EARLY TOMORROW MORNING. MODERATES WINDS ARE
EXPECTED AT THE SURFACE GIVEN THE STRONG GRADIENT PRESENT.
WHEREIN...WINDS UP TO 25/30 MPH ARE EXPECTED WITH SLIGHTLY
STRONGER WINDS OVER THE BERING STRAIT COAST AND ST LAWRENCE
ISLAND.

ISOLATED TO SCATTERED SHOWERS EXPECTED ACROSS MUCH OF THE WEST
COAST TO CENTRAL INTERIOR OVERNIGHT...WITH INCREASED CHANCES THEN
SPREADING TO THE EASTERN INTERIOR TOMORROW. DRYING TREND BEGINS
TOMORROW EVENING AND TOMORROW NIGHT AS SFC HIGH PRESSURE BUILDS
OVER THE WEST COAST...WITH THE DRYING TREND SPREADING EASTWARD
MON.

.COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE.

HIGH SURF ADVISORY REMAINS IN EFFECT FOR ZONE 207...SPECIFICALLY
FROM SHISHMAREF WEST...UNTIL NOON SUN. NO CHANGE IN THE ADVISORY
WITH A SURGE OF ABOUT 1 FOOT STILL EXPECTED.

&&

.FIRE WEATHER...NO CONCERNS. COOL...CLOUDY...AND WET CONDITIONS
WILL PREVAIL OVERNIGHT AND TOMORROW. 500 MB MID-LEVEL RIDGE STARTS
BUILDING INTO SOUTHWEST AND THE NORTHEAST BERING SEA MON. THIS
WILL BEGIN A DRYING TREND BEGINNING FROM THE WEST COAST TO THE
EASTERN INTERIOR AS THE RIDGE ALOFT PUSHES EAST TO CENTRAL
MAINLAND AK BY WED.

&&

.HYDROLOGY...THE FLOOD ADVISORY FOR THE CHENA RIVER UPSTREAM OF
THE MOOSE CREEK DAM WAS EXTENDED 24-HRS. THIS MORNING...THE CREST
OF HIGH WATER IS AT CHENA LAKES THIS MORNING AND THE US ARMY CORPS
OF ENGINEERS ALASKA DISTRICT BEGAN OPERATING THE MOOSE CREEK
DAM...REGULATING THE CHENA RIVER. LOW LYING AREAS NEAR THE CHENA
RIVER MAY EXPERIENCE MINOR FLOODING AND GROUNDWATER WILL RISE TO
NEAR THE GROUND SURFACE FOR SEVERAL THOUSAND FEET WEST OF THE
MOOSE CREEK DAM.

ELSEWHERE...NO HYDROLOGIC CONCERNS. WATER LEVELS IN THE WESTERN
ALASKA RANGE CONTINUE TO FALL. KUSKOKWIM RIVER AT MCGRATH LOOKED
TO HAVE CRESTED THIS MORNING SO SPS WAS ALLOWED TO EXPIRE IN
REGARD TO HIGH WATER MOVING DOWN.

&&

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

WINTER STORM WARNING FOR AKZ206.

SMALL CRAFT ADVISORY FOR PKZ200-PKZ210-PKZ215-PKZ220-PKZ225-
PKZ245.

&&

$$

ET AUG 15


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