Storm Warning 1, NWS Fairbanks, AK

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
506 AM AKST FRI JAN 1 2010

.DISCUSSION...
THE FIRST OF A SERIES OF SHORT WAVES ALOFT...ACCOMPANIED BY A
VIGOROUS SURFACE LOW...SWEPT THROUGH THE SOUTH BEAUFORT SEA
YESTERDAY AND IS NOW FAR AWAY IN THE CANADIAN ARCTIC. THE SECOND
SHORT WAVE AND LOW PRESSURE SYSTEM ARE NOW APPROACHING THE ALASKA
ARCTIC COAST AND THERE IS PLENTY OF WINDSWEPT ACTION...BARTER
ISLAND WITH WESTERLY GUSTS TO 47 KNOTS /54 MPH/ AND AT DEADHORSE
WIND CHILLS TO -53 DEGREES F. THIS IS NOT A BIG STORM BY ANY MEANS
BUT IT IS MORE PHYSICAL THAN THE YESTERDAYS SYSTEM.

THE WINDS WITH THIS SYSTEM ARE EXPECTED TO BE REACHING THEIR
STRONGEST TODAY...AND TO BEGIN DROPPING OFF LATE TONIGHT. THE
CLOUDS THAT MOVED IN WITH THE FIRST AND SECOND ARCTIC WEATHER
SYSTEMS ON TODAYS MAP REMAIN THIS MORNING...BUT THEY ARE MAINLY
CONFINED TO THE ARCTIC PLAIN...WHILE THE BROOKS RANGE IS MOSTLY IN
THE CLEAR.

THE THIRD...AND PROBABLY FINAL...SHORT WAVE ALOFT AND LOW PRESSURE
SYSTEM IN THIS SERIES IS FAR FAR AWAY AROUND 85 DEGREES NORTH
LATITUDE AND THE DATELINE. THE MOST RECENT AVAILABLE POLAR
ORBITING SATELLITE IMAGERY OVER THE ARCTIC BASIN IS FROM YESTERDAY
/THURSDAY/ AFTERNOON SO THERE IS NOT ENOUGH TO SUBSTANTIATE THIS
WITH ANY CERTAINTY. IN ITS LAST TWO RUNS...THE GSM MODEL HAS
FORECAST THIS LAST SYSTEM IN THE SERIES TO HAVE LITTLE STRENGTH
COMPARED TO ITS PREDECESSORS.

THE FOCUS THEN SHIFTS TO THE BERING SEA FOR SUNDAY AND EARLY NEXT
WEEK. THE GSM MODEL FORECASTS MODERATE LOW PRESSURE AND GALE FORCE
WINDS TO SPREAD OVER THE BERING SEA...ESPECIALLY THE SOUTHEAST
QUADRANT...STARTING SUNDAY. THIS DEVELOPMENT IS EXPECTED TO BRING
GALE FORCE WINDS TO THE BERING SEA COAST BUT NOT MUCH SNOWFALL.

IN CONJUNCTION WITH THIS...RETURN FLOW ALOFT FROM THE GULF OF
ALASKA UP OVER THE INTERIOR OF NORTHERN ALASKA IS EXPECTED TO SET
IN MONDAY AND TUESDAY. THIS IS NOT SET UP TO BRING IN A CHINOOK
SO THE INTERIOR TEMPERATURE FORECASTS ARE CONSERVATIVE.
STILL...THE GSM MODEL FORECASTS TEMPERATURES AT 850 MILLIBARS
/ABOUT 5000 FEET ABOVE SEA LEVEL/ OVER THE SOUTHEAST INTERIOR
ZONES TO RISE FROM THE PRESENT -15 TO -22 DEGREES C TO -4 DEGREES
C BY TUESDAY. THIS IS ENOUGH TO BRING SUBSTANTIAL CHANGE...PERHAPS
20 FAHRENHEIT DEGREES.

POLAR ORBITING SATELLITE IMAGERY OVER THE ALASKA MAINLAND
OVERNIGHT...AS DID THE IMAGERY YESTERDAY...SHOWS A VERY LARGE AREA
OF UNDISTURBED OVERCAST STRATOCUMULUS COVERING THE ENTIRE
SOUTHEAST INTERIOR...JUST ABOVE EVERYWHERE SOUTH OF FORT YUKON AND
EAST OF TANANA. INCREASING NORTHEAST FLOW ALOFT...WHICH IS
EXPECTED LATER TODAY AND TONIGHT...SHOULD START TO CLEAR
THIS...BUT IT MAY TAKE A FULL DAY TO ACCOMPLISH...AND THE
REMAINING CLOUDS WILL PROBABLY BE TRAPPED ON THE NORTH SIDE OF THE
ALASKA RANGE FOR ONE OR TWO DAYS.

LOW CLOUDS ALSO SETTLED IN OVER THE NORTH SLOPES OF THE CENTRAL
ALASKA RANGE AND OVER THE UPPER KUSKOKWIM VALLEY /ZONES AKZ225 AND
227/ ON THURSDAY. THESE NOW APPEAR TO BE THINNING AND STARTING TO
CLEAR WITHIN AN AREA OF INCREASING NORTHEAST FLOW ALOFT.

A BAND OF CLOUDS HAS REMAINED FROM THE GULF OF ANADYR TO THE YUKON
DELTA FOR OVER 12 HOURS. NO PRECIPITATION HAS BEEN REPORTED WITH
THIS DECK OF CLOUDS...WHICH IS BEING STRETCHED OUT BY OPPOSING AIR
FLOW...SOUTHEASTERLY OVER THE DELTA AND NORTHWESTERLY OVER NEARLY
ALL OF THE MAINLAND.

IN THE MEDIUM RANGE...BOTH THE EUROPEAN AND GFS COMPUTER MODELS
FORECAST THE ONSET OF RETURN FLOW OVER THE INTERIOR EARLY NEXT
WEEK IN SIMILAR FASHION. THE MODEL FORECASTS DIVERGE SOME STARTING
WITH THE FORECAST FOR FRIDAY. UP TIL THAT POINT...THE MODELS
FORECAST MILD SOUTHERLY FLOW OVER MUCH OF THE ALASKA MAINLAND.
THIS IS A WELCOME PROSPECT HEADING INTO JANUARY.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FOR AKZ203. BLIZZARD WARNING FOR AKZ024.

GALE WARNING FOR PKZ245.

BRISK WIND ADVISORY FOR PKZ235-PKZ240.
&&

TF JAN 10