Snow Advisory 4, NWS Fairbanks, AK

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
534 AM AST MON JAN 15 2007

.DISCUSSION...
A PAIR OF LOWS ALOFT HAVE SETTLED IN OVER THE ALASKA MAINLAND. THE
FIRST IS NEAR BARROW AND THE SECOND NEAR MCGRATH. A VERY SMALL
SURFACE LOW REMAINS JUST NORTH OF KOTZEBUE. THIS FEATURE IS NOT
RESOLVABLE ON THE MODELS. NOR IS THE SUPER GRADIENT WEST WIND AT
DEERING AND BUCKLAND WHICH ARE BOTH 15 TO 25 KNOTS. THIS NARROW
WESTERLY JET SOUTH OF KOTZEBUE FORMS WHEN NORTH FLOW ALOFT /WHICH
WE HAVE THIS MORNING/ IS BLOCKED BY THE HILLS OF THE SEWARD
PENINSULA. KOTZEBUE ITSELF ONLY HAS 5 TO 10 KNOTS OF WEST WIND.

THE 00Z MODELS WERE IN CLOSE AGREEMENT EXCEPT ALONG THE ARCTIC
COAST WHERE THE MESO ETA VERY WELL RESOLVED THE SMALL SURFACE LOW
ELONGATED JUST OFFSHORE THE COAST FROM KOMAKUK BEACH TO ONSHORE
JUST NORTH OF ATQUASUK. THIS FEATURE OFTEN APPEARS WHEN VIGOROUS
GULF OF ALASKA DISTURBANCES ENTER THE SOUTH YUKON TERRITORY. SOME
OF THE CYCLONIC CIRCULATION FROM THESE SYSTEMS IS TRANSFERRED TO
THE SOUTHEAST BEAUFORT SEA AS THE PARENT MARITIME LOWS SHATTER
OVER THE RUGGED MOUNTAINS OF THE NORTH GULF COAST. THE MESO ETA
MODEL FORECASTS THIS WEAK ELONGATED LOW TO WEAKEN LATER TODAY AND
TONIGHT AND FOR ALL TRACES OF IT TO EXIT THE SCENE LATE TUESDAY.

THE MODELS FORECAST THE LAST TRACES OF PRECIPITATION ASSOCIATED
WITH YESTERDAYS GULF OF ALASKA LOW TO END OVER THE MAINLAND EARLY
TUESDAY. THE NEXT SYSTEM ON TAP IS SOUTH OF THE END OF THE
ALEUTIAN CHAIN. THE GFS FORECASTS AN ENERGETIC BREAKOFF CENTER
FROM THIS SYSTEM TO ENTER BRISTOL BAY TUESDAY EVENING AND THEN
NORTON SOUND WEDNESDAY EVENING. ALTHOUGH THIS SYSTEM WILL BE
WEAKENING AS THIS TRANSPIRES BRISK NORTH WINDS WILL BLOW FROM
BERING STRAIT TO SAINT LAWRENCE ISLAND AND A FAIR SIZED INFLUX OF
MOISTURE WILL OCCUR OVER THE WESTERN AND CENTRAL MAINLAND TUESDAY
EVENING THROUGH WEDNESDAY NIGHT. OVER THE EAST MAINLAND A MODERATE
SOUTH CHINOOK WILL BEGIN TUESDAY NIGHT AND STRENGTHEN WEDNESDAY
NIGHT. SOME COOLING IS FORECAST THURSDAY NIGHT AS THE CHINOOK
WEAKENS. THE MEDIUM RANGE MODELS FORECAST AN ONGOING SERIES OF
SHORT WAVE RIDGES AND TROUGHS INCOMING FOR THE REST OF THE
WEEK. THUS CHANGEABLE WEATHER AND RELATIVELY MILD TEMPERATURES CAN
BE FORECAST WITH SOME CONFIDENCE. A RECURRENCE OF 40 BELOW WEATHER
MAY STILL COME THIS WINTER...BUT AT THIS TIME IT TAKES SOME
IMAGINATION TO SEE IT.

SATELLITE IMAGERY SHOWS OVERCAST CLOUD COVER NEARLY EVERYWHERE
EXCEPT THE WEST BROOKS RANGE. A NEARLY PERFECT CIRCULAR AREA OF
STRATUS AND STRATOCUMULUS...WITH A RADIUS AROUND 150 MILES...HAS
DRIFTED WESTWARD ABOUT 5 KNOTS AND IS DIRECTLY OVER BARROW NOW.
THIS FEATURE IS PART OF THE CYCLONIC CIRCULATION THAT WAS
TRANSFERRED UP INTO THE SOUTHEAST BEAUFORT SEA ON SUNDAY.
EXTENSIVE LOW CLOUDS WILL REMAIN OVER THE WEST TODAY BUT CLEAR
RAPIDLY TONIGHT AS WINDS SHIFT TO THE NORTHEAST WHICH IS OFFSHORE.

COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NORTHERLY GALE GUSTS
BERING STRAIT DOWN ACROSS SAINT LAWRENCE ISLAND.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
SNOW ADVISORY FOR AKZ222.
&&

TF JAN 07