Brisk Wind Advisory 83, NWS Fairbanks, AK

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
444 AM ADT TUE MAR 18 2008

.DISCUSSION...THE NAM AND GFS MODELS HAVE VERY SIMILAR FORECASTS
THROUGH THURSDAY MORNING. ALOFT...A LARGE AREA OF COLD LOW
PRESSURE OVER THE MAINLAND WILL SINK DOWN TO THE SOUTH PART OF THE
ALASKA MAINLAND. THIS WILL RESULT IN INCREASED EAST FLOW OVER THE
INTERIOR AND INCREASED NORTH FLOW OUT ON THE CHUKCHI AND BERING
SEA COASTS. BELOW NORMAL TEMPERATURES AND CHILLY NORTHEAST WINDS
WILL BE THE RULE OVER MUCH OF THE REALM.

AS HAD BEEN EXPECTED...A SMALL SURFACE LOW PRESSURE CENTER FORMED
JUST OFFSHORE PRUDHOE BAY OVERNIGHT. THIS FEATURE IS FORECAST BY
THE MODELS TO DISSIPATE AS IT IS ABSORBED INTO THE PREVAILING
LIGHT NORTHEAST FLOW OVER THE AREA LATER TODAY. THIS MORNINGS
POLAR ORBITING SATELLITE IMAGERY SHOWS NO SIGN OF CIRCULATION
AROUND THIS SMALL LOW.

MORNING SATELLITE IMAGERY SHOWS THAT CLOUDS HAVE ADVANCED
NORTHWARD OVER THE UPPER YUKON VALLEY WHILE REMAINING OVER THE
SOUTHERN INTERIOR...EASTERN NORTON SOUND AND THE YUKON DELTA. THE
ONLY PRECIPITATION OF ANY CONSEQUENCE THIS MORNING IS ON THE
COAST SOUTH OF UNALAKLEET...THE YUKON DELTA AND THE LOWER YUKON
VALLEY.

AS IT WAS YESTERDAY...THE PRESSURE GRADIENT OVER THE BROOKS RANGE
IS STRONG THIS MORNING. THE MOST SEVERE WIND CHILLS WITH THIS WILL
BE IN BROOKS RANGE PASSES...WHERE COLD AIR FROM THE NORTH AND FAST
CHANNELED WINDS ARE CAUSING WIND CHILLS TO 65 BELOW. IN THE
SOUTHERN INTERIOR TEMPERATURES ARE NOT LOW ENOUGH AND ON THE
ARCTIC COAST THE WINDS ARE TOO LIGHT FOR WIND CHILL ADVISORIES.
THE PRESENT AREAS OF LOW WIND CHILLS WILL PROBABLY REMAIN PAST
WEDNESDAY MORNING...THE MAP PATTERN FOR WIND CHILLS IS NOT
FORECAST TO CHANGE MUCH.

A NEW FEATURE ON THE NAM AND GFS FORECASTS IS THE DEVELOPMENT OF A
STRONG TEMPERATURE GRADIENT EXTENDING FROM THE CENTRAL YUKON TO
THE WESTERN ALASKA RANGE LATER TODAY...AND STRENGTHENING TONIGHT
AND THURSDAY. ON THURSDAY NIGHT THE MODELS FORECAST THIS ARCTIC
FRONT TO SHIFT WESTWARD. ON TOP OF THIS FRONT THERE WILL BE A
WEAK CYCLONIC INFLUX OF GULF OF ALASKA MARITIME AIR MODIFIED BY
ITS INEVITABLE PASSAGE OVER THE COASTAL AND ALASKA RANGES.
THIS...IN MORE STRAIGHTFORWARD LANGUAGE MEANS THAT AN OUTBREAK OF
SNOW OVER THE SOUTHEAST HALF OF THE INTERIOR AND LATER THE CENTRAL
INTERIOR SHOULD GET STARTED TONIGHT. THIS SNOWFALL COULD BE
SEVERAL INCHES DEEP BY EARLY THURSDAY MORNING IF EVERYTHING WORKS
OUT.

THE MEDIUM RANGE FORECASTS ARE FUNCTIONALLY SIMILAR FOR NORTHERN
ALASKA OUT THROUGH LATE NEXT WEEK...KEEPING THE MAINLAND OF ALASKA
UNDER A LARGE TROUGH ALOFT. COOLER THAN NORMAL TEMPERATURES APPEAR
LIKELY OVER THE ENTIRE MAINLAND. THE FORECASTS OVER THE SOUTH
BERING SEA DIFFER SIGNIFICANTLY STARTING MONDAY OF NEXT WEEK...BUT
THIS DIFFERENCE HAS LITTLE AFFECT ON THE FORECAST THINKING FOR
THIS PART OF THE WORLD.

&&

AFG WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY FOR AKZ207-AKZ208-AKZ217-AKZ218-AKZ219-
AKZ220.

WIND CHILL WARNING FOR AKZ205-AKZ206.

GALE WARNING FOR PKZ225.

BRISK WIND ADVISORY FOR PKZ210-PKZ220.
&&

TF MAR 08