Snow Advisory 4, NWS Fairbanks, AK

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
201 PM AST MON DEC 5 2005

.DISCUSSION...
DYNAMIC PATTERN WITH MUSCULAR CLOSED LOW ALOFT NEAR AMCHITKA
SPONSORING 977 MB SURFACE LOW JUST TO THE EAST. DOWNSTREAM
RIDGE EXTENDS FROM EASTERN GULF OF ALASKA NORTHWESTWARD TO
BERING STRAIT. UP NORTH...POLAR CLOSED LOW OVER NORTHERN GREENLAND
EXTENDING TROUGH SOUTHWESTWARD TO POINT BARROW. BROAD BELT OF
SURFACE HIGH PRESSURE EXTENDS FROM 1050 MB HIGH OVER EAST CENTRAL
SIBERIA EASTWARD TO 1040 MB SURFACE HIGH OVER WESTERN CANADA.
PATTERN IS BATHING SOUTHERN HALF OF THE STATE IN STRONG
WESTERLY FLOW ALOFT WITH LIGHTER FLOW ALOFT FOR THE NORTHERN
HALF.

MODELS...REASONABLE CONSENSUS TRANSLATES AMCHITKA CLOSED LOW
EASTWARD TOWARD DUTCH HARBOR PUSHING DOWNSTREAM RIDGE EAST TO THE CANADA
BORDER. ASSOCIATED SURFACE LOW DEEPENS STEADILY UNDER DYNAMIC
SPONSORSHIP FALLING INTO THE 950S MB AS IT MOVES. BROAD SOUTHERLY
FLOW WILL BUILD CHINOOK INTO THE INTERIOR ON TUESDAY AS SURFACE
TROUGH POKES FROM AROUND DUTCH HARBOR NORTHEASTWARD TO KOTZEBUE
SOUND. RIDGE RETREATS LATE TUESDAY TO ALLOW STRAIGHT SHOT FOR
SOUTHERLY FLOW ALOFT ALL THE WAY NORTH TO THE BROOKS RANGE.
SURFACE HIGH PRESSURE BELT WILL SHIFT NORTHWARD TO LIE NORTH OF
THE ARCTIC COAST BY LATE TUESDAY AND KEEPING SURFACE PRESSURE GRADIENT
TIGHT WITH DEEPENING SYSTEM NEAR DUTCH HARBOR. WEDNESDAY
MORNING...DUTCH HARBOR LOW SHIFTS TO BRISTOL BAY TO BEGIN SLOW
ARDUOUS FILLING AS DYNAMIC SPONSORSHIP ERODES.

NORTH SLOPE...STEADY INCREASE IN EAST WIND SPEEDS ON TAP FOR THE
NEXT COUPLE OF DAYS AS ALEUTIAN STORM DEEPENS RAPIDLY NEAR DUTCH
HARBOR AND RELENTLESS HIGH PRESSURE FROM SIBERIA TO WESTERN CANADA
GIVES GROUND SLOWLY TO THE NORTH. WITH WARM PUSH FROM THE
SOUTH...SOME MODEST WARM UPS ON TAP GOING TOWARD THE WEEKEND.
USUAL ROUNDS OF CLOUDS AND FLURRIES WILL PERSIST WITH ONSHORE
WINDS...WITH SOME MORE SUBSTANTIAL SNOW SHOWERS WORKING IN FROM
THE SOUTH ON WEDNESDAY. MARINERS...BRISK WINDS WEST OF POINT
BARROW WILL EXTEND OVER ALL OF THE NORTH SLOPE BY LATE TUESDAY.
GALES POSSIBLE LATE WEDNESDAY WEST OF ICY CAPE.

WEST COAST...STORMY TIME AHEAD AS 980S MB SURFACE LOW NEAR
AMCHITKA DEEPENS RAPIDLY TO 950S MB NEAR DUTCH HARBOR BY LATE
TUESDAY INTO WEDNESDAY. LEADING TROUGH FROM ALEUTIANS
NORTHEASTWARD TO NORTON SOUND WILL ALLOW SOUTHWEST FLOW TO PUSH
SHOWERS AND MORE SUBSTANTIAL SNOWS INTO EASTERN NORTON SOUND AND
THE NULATO HILLS. TROUGH WILL TRANSLATE NORTHWARD AND DEEPEN
RAPIDLY ON TUESDAY FROM DUTCH HARBOR TO KOTZEBUE...AND SNOW
WILL BE WIDESPREAD FROM KOTZEBUE SOUTHWARD. THESE WILL CONTINUE
SMEAR NORTHWARD ALONG THE WEST COAST AS SURFACE LOW COILS UP OVER
WESTERN BRISTOL BAY AND TROUGH SWINGS CYCLONICALLYY ABOUT THE
SURFACE CENTER. MARINERS...BRISK WINDS FOR THE NEXT SEVERAL
DAYS...WITH GALES FROM SAINT LAWRENCE ISLAND WESTWARD AND OVER THE
CHUKCHI SEA OUTER WATERS THROUGH WEDNESDAY. THINGS SHOULD START
TAPERING OFF TOWARD THE LAST HALF OF THE WORK WEEK.

INTERIOR...WET GLOPPY MARINE AIR WITH ASSOCIATED SNOWFALL GETTING
STARTED FROM KALTAG TO NORTHWAY AND ALONG THE ALASKA RANGE. AS
SURFACE TROUGH DEEPENS FROM ALEUTIANS TO NORTON SOUND
TONIGHT...EXPECTING SNOW TO BECOME MORE WIDESPREAD IN THIS BASIC
AREA WITH HEAVIEST AMOUNT...2 TO 3 INCHES...SOUTHERN YUKON DELTA
AND LOWER YUKON VALLEY. DYNAMIC DAY IN STORE TUESDAY AS SURFACE
TROUGH SHIFTS NORTHWARD AND LIES FROM DEEPENING DUTCH HARBOR LOW
TO KOTZEBUE SOUND. CIRCULATION WILL TUG MORE MOIST MARINE AIR INTO
WESTERN INTERIOR AND SPREAD SNOW INTO CENTRAL INTERIOR. TANANA
VALLEY WILL BE SPARED DUE TO THE CHINOOK ALOFT...BUT 4 INCHES
WITHIN REACH OVER THE MIDDLE YUKON AND LOWER KOYUKUK VALLEYS FROM
ANVIK TO HUSLIA WITH LESSER AMOUNTS TO THE EAST. SLOW TAPERING OFF
TUESDAY NIGHT INTO WEDNESDAY AS INTERIOR FLOW IS UNIFORMLY SPEEDY
AND SOUTHERLY...AND 5340 DAM 1000 TO 500 MB THICKNESS LINE WILL
HAVE PUSHED TO A NOME TO FORT YUKON LINE. WILL BE MONITORING
CLOSELY FOR POSSIBLE WIND AND HEAVY SNOW PROBLEMS AS THIS STORM
UNFOLDS.

MEDIUM RANGE...PLAUSIBLE SOLUTION SHEARING BIG TROUGH EASTWARD INTO
CANADA WITH WEAK RIDGE BUILDING NORTHWARD INTO THE SOUTHERN BERING
SEA BY THE WEEKEND. PATTERN SHOULD BE CALMER ACROSS THE
BOARD...FAST FLOW DISPLACED TO THE SOUTH WILL REDUCE DYNAMIC
SUPPORT FOR ORGANIZED SNOWFALL...WEAK EASTERLY FLOW WILL RETURN TO
THE INTERIOR. SURFACE LOW NEAR MACKENZIE DELTA LATE IN THE WEEK
WILL SHIFT WINDS BACK TO THE WEST OVER THE NORTH SLOPE.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FOR AKZ219-AKZ220-AKZ221.

HEAVY FREEZING SPRAY WARNING FOR PKZ210.

GALE WARNING FOR PKZ210.

BRISK WIND ADVISORY FOR PKZ220-PKZ225-PKZ230.
&&

TS DEC 05