Gale Warning 44, NWS Fairbanks, AK

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
546 AM AKDT WED MAR 25 2009

.DISCUSSION...THE NAM AND GFS MODELS HAVE VERY SIMILAR FORECASTS,
SO THERE ARE NO MATTERS TO RESOLVE REGARDING MODEL DIVERGENCE. THE
GFS AND EUROPEAN MODELS BOTH FORECAST A LONG LIVED COLD TROUGH
ALOFT TO HOLD OVER THE ALASKA MAINLAND UNTIL IT IS EXPECTED TO
NUDGE WESTWARD AND LET IN SOME RETURN FLOW FROM THE GULF OF ALASKA
OVER THE WEEKEND. EARLY NEXT WEEK BOTH MODELS FORECAST THE VERY
PERSISTENT TROUGH ALOFT TO REESTABLISH ITSELF OVER MAINLAND
ALASKA. OVERALL, THIS PATTERN FAVORS LITTLE PRECIPITATION AND
SOMEWHAT COLDER THAN NORMAL TEMPERATURES IN NORTHERN ALASKA.
TEMPERATURES ARE EXPECTED TO BE MOST BELOW NORMAL OUT WEST OF 155
DEGREES LONGITUDE.

A 972 MB LOW NEAR 50 DEGREES NORTH 164 DEGREES WEST HAS BEEN
MOVING NORTHEAST ABOUT 20 MPH OVER THE PAST 18 HOURS. THE PARENT
CENTER IS STUCK DOWN IN THE MIDDLE LATITUDES AND THE FRONT AHEAD
OF IT HAS SPRUNG AWAY -- A PATTERN OFTEN SEEN IN NORTH PACIFIC
LOWS. IN THIS CASE, NOT MUCH PRECIPITATION LOOKS LIKELY OUTSIDE OF
THE GULF OF ALASKA COAST. MUCH OF THE WEATHER WILL BE WIND, WITH
WHICH THERE WILL BE SOME BLOWING SNOW. TEMPERATURES IN NORTHERN
ALASKA SHOULD CREST TOMORROW OR FRIDAY. VERY FEW IF ANY LOCATIONS
IN NORTHERN ALASKA WILL HAVE TEMPERATURES REACHING FREEZING.

THERE IS A PERSISTENT TROUGH OF LOW PRESSURE HOLDING OVER THE WEST
COAST OF THE REALM. THIS IS A COMMON WINTER FEATURE. THE COLD
NORTH FLOW COMING DOWN TO THE WEST OF IT IS EXPECTED TO REACH FULL
GEOSTROPHIC POTENTIAL AND PERHAPS TO BE SUPER GRADIENT WHERE/WHEN
IT IS ENHANCED BY TOPOGRAPHY (AS IT HAS BEEN FOR ALMOST 2 DAYS) OR
AIRMASS INSTABILITY AND THE ACCOMPANYING GUST FACTORS.

ONLY AFTER THE CIRCULATION AROUND THIS INBOUND PACIFIC LOW
DIMINISHES WILL THERE BE MUCH CHANCE OF SNOWFALL IN NORTHERN
ALASKA. IN SUCH SITUATIONS, PRECIPITATION IS TYPICALLY NOT REAL
ORGANIZED, RATHER, IT APPEARS RANDOMLY DISTRIBUTED. IE.,
SCATTERED.

TEMPERATURES AND WINDS IN THE NORTHERN INTERIOR HAVE GENERALLY
MODERATED SO A NUMBER OF WINTER WEATHER AND WIND ADVISORIES HAVE
ENDED. THE ZONES MOST AFFECTED BY WIND WILL BE NUMBERS 208, 217
AND 218 -- ON THE SOUTH SLOPES OF THE BROOKS RANGE. THE SEWARD
PENINSULA IS ALSO LIKELY TO BE AFFECTED, THOUGH HIGH WINDS SEEM
OUT OF REACH OUT THERE IN THIS CASE.

LATE NIGHT SATELLITE IMAGERY SHOWS LOTS OF CLEAR WEATHER OVER THE
SEWARD PENINSULA UP OVER KOTZEBUE SOUND, THE BROOKS RANGE AND THE
ARCTIC. CLOUDS ARE RAPIDLY ADVANCING TOWARD THE BROOKS RANGE AT
THIS TIME.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FOR AKZ217.

WINTER WEATHER ADVISORY FOR AKZ218.

GALE WARNING FOR PKZ210.

BRISK WIND ADVISORY FOR PKZ200-PKZ210-PKZ220-PKZ225-PKZ230.
&&

TF MAR 09