Blizzard in Alaska, February 22, 2008

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
156 PM AST FRI FEB 22 2008

.DISCUSSION...
THE LONG ADVERTISED PATTERN CHANGE IS UNDERWAY. THE OPERATIONAL
MODELS AND ENSEMBLES CONTINUE TO REMAIN IN ABOVE AVERAGE AGREEMENT
THROUGH THE MIDDLE OF NEXT WEEK.

A RIDGE IS BUILDING TODAY ACROSS THE WESTERN ALEUTIANS AHEAD OF AN
UPPER LOW THAT IS SEEN ON SATELLITE PICTURES NEAR 45N 170E. THIS
RIDGE WILL CONTINUE TO STRONGLY BUILD ACROSS THE BERING SEA THIS
WEEKEND. MODELS/ENSEMBLES ARE IN A TIGHT CLUSTER THAT A CLOSED
500MB HIGH WILL BE FOUND NEAR WRANGLE ISLAND BY THE MIDDLE OF NEXT
WEEK. THIS WILL LEAD TO A MUCH MORE SEASONABLE PATTERN ACROSS
NORTHERN ALASKA.

AT THE SURFACE...A 1000 MB LOW IN MACKENZIE BAY WILL SLOWLY FILL
AS IT SLIDES OFF TO THE EAST TONIGHT AND SATURDAY. AT THE SAME
TIME A BUILDING HIGH ALONG THE CHUKOTSK PENINSULA WILL MOVE TO
NEAR THE BERING STRAIT BY SATURDAY AFTERNOON.

NORTH SLOPE...THE WORST WEATHER WILL BE FOUND FROM ABOUT NUIQSUT
AND POINTS EAST TONIGHT. STRONG COLD AIR ADVECTION AND
SUPERGEOSTROPHIC FLOW WILL PRODUCE STRONG WIND AND AREAS OF
BLOWING SNOW WITH ZERO VISIBILITY AT TIMES. UPGRADED THE BLOWING
SNOW ADVISORY THAT WAS ISSUED EARLIER ON SHIFT TO A BLIZZARD
WARNING FOR ZONE 204. THE VISIBILITY HAS BEEN TRENDING DOWN THE
LAST FEW HOURS AND WILL ISSUE A BLOWING SNOW ADVISORY FOR 203.
CONDITIONS SHOULD BEGIN TO IMPROVE BY MORNING IN THE DEADHORSE
AREA...BUT FURTHER EAST BLIZZARD CONDITIONS WILL LIKELY PERSIST
UNTIL NOON.

FROM BARROW WEST MUCH DRIER AIR WILL FILTER IN AT MID AND UPPER
LEVELS WITH THE WIND SLACKENING OFF AS THE SURFACE RIDGE BUILDS
INTO THE AREA LATER TONIGHT AND SATURDAY.

IT LOOKS LIKE THE MODELS ARE UNDER-DOING THE WIND A BIT AND WILL
ALSO HAVE A GALE WARNING FOR THE NORTHEAST ARCTIC COAST. WILL ALSO
NEED TO KEEP AN EYE ON THE WIND CHILLS THIS WEEKEND...MAINLY IN
ZONE 205 WHERE SOME STRONGER NORTH WIND THROUGH THE PASSES MAY
PRODUCE WIND CHILLS CLOSE TO ADVISORY CRITERIA.

WEST COAST...AS THE UPPER RIDGE BUILDS ACROSS THE BERING SEA AND THE
SURFACE RIDGE BUILDS IN ALONG THE WEST COAST THE WEATHER WILL
FINALLY CLEAR OUT AND SETTLE DOWN.  STILL ENOUGH WIND AND LOW ENOUGH
TEMPERATURES ON THE SEWARD PENINSULA FOR SOME WIND CHILL CONCERNS
THROUGH THIS EVENING. LOCALLY IN KOTZEBUE THERE HAVE BEEN SOME LOW
VISIBILITIES IN BLOWING SNOW TODAY.  THE WIND SHOULD DROP OFF
THIS EVENING AS A WEAK SURFACE TROUGH BEGINS TO DROP SOUTH OF THE
AREA. AS THE RIDGE CONTINUES TO BUILD EARLY NEXT WEEK TEMPERATURES
WILL MODERATE BACK TO SLIGHTLY ABOVE AVERAGE LEVELS BY EARLY NEXT
WEEK.

INTERIOR...OUT AHEAD OF AN UPPER TROUGH THE FLOW WILL BECOME MORE
WEST TO SOUTHWEST THIS WEEKEND.  THIS WILL PRODUCE A CHANCE OF SNOW
ACROSS MUCH OF THE INTERIOR. DRIER AIR WILL BEGIN TO WORK IN FROM
THE WEST ON SUNDAY FROM ABOUT BETTLES TO RUBY AND POINTS
WEST...BUT AREAS OF LOW CLOUDS AND LIGHT SNOW WILL LIKELY PERSIST
EAST OF THIS LINE THROUGH SUNDAY. BY MONDAY THE AREAS OF LIGHT
SNOW SHOULD BE CONFINED TO AREAS EAST OF FAIRBANKS. RIGHT NOW IT
LOOKS DRY AND SEASONABLE ACROSS THE INTERIOR TUESDAY AND WEDNESDAY
OF NEXT WEEK.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY FOR AKZ207-AKZ210.

BLIZZARD WARNING FOR AKZ204.

BLOWING SNOW ADVISORY FOR AKZ203.

GALE WARNING FOR PKZ245.

BRISK WIND ADVISORY FOR PKZ210-PKZ215-PKZ220-PKZ240.
&&

CB FEB 08