High Wind in Alaska, December 21, 2009

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
546 AM AKST MON DEC 21 2009

.DISCUSSION...
THE LAST IN A SERIES OF NORTH PACIFIC LOWS WILL CONTINUE TO HAVE A
HIGH IMPACT ALONG THE WEST COAST THROUGH TONIGHT...AND WILL BEGIN TO
PULL AWAY FROM THE STATE ALLOWING THE STORMY WEATHER TO GRADUALLY
WIND DOWN BY LATE TUESDAY.

A 956 MB LOW BETWEEN COLD BAY AND THE PRIBILOF ISLANDS EARLY THIS
MORNING WILL ROTATE TO THE NORTHWEST TODAY...AND WILL END UP NEAR
SAINT MATTHEW ISLAND AT 3 PM THIS AFTERNOON. THE LOW WILL CONTINUE
TO LIFT OUT TO THE NORTHWEST TONIGHT AROUND A LARGE AND COMPLEX
UPPER LOW IN THE BERING SEA. THE MODELS ARE IN BETTER AGREEMENT
THAN THEY HAVE BEEN WITH THE EVOLUTION OF THE LOW...AND THE NAM
WHICH HAD BEEN A STRONG OUTLIER IS FINALLY MORE IN STEP WITH THE
GFS/ECMWF/UKMET.

WEST COAST...THE MOST SIGNIFICANT WEATHER WILL CONTINUE TO IMPACT
THE WEST COAST ZONES. ANOTHER SLUG OF MOISTURE IS SEEN ON SATELLITE
PICTURES AND RADAR LIFTING NORTH ASSOCIATED WITH THE BERING SEA
SURFACE LOW. THE PHASE OF THE PRECIPITATION IS BECOMING AN
INCREASING CHALLENGE AS THERE HAS BEEN A FLOOD OF WARM AIR INTO THE
YUKON DELTA AND LOWER YUKON VALLEY.  THE SNOW EVEN CHANGED OVER TO
FREEZING RAIN FOR A TIME EARLIER THIS MORNING AT NOME. WHAT
CONTINUES TO LOOK LIKE A LOCK IS A PROLONGED PERIOD OF BLIZZARD
CONDITIONS ALONG THE BALDWIN PENINSULA AND THE CHUKCHI SEA COASTS
INTO TONIGHT AS WELL AS HEAVY SNOW ACROSS THE NULATO HILLS INTO THIS
EVENING. THE PRECIPITATION ACROSS THE Y-K DELTA COAST AND LOWER
YUKON VALLEY MAY GO BACK AND FORTH BETWEEN RAIN AND SNOW.  SOME OF
THE RAIN MAY FREEZE ON COLDER SURFACES AS THE AREA IS COLD SOAKED
FROM THE VERY COLD WEATHER LAST WEEK. WILL MAINTAIN MOST OF THE
BLIZZARD WARNINGS...BUT WILL HAVE TO DOWNGRADE THE BLIZZARD WARNING
TO WINTER STORM WARNING IN ZONES 214 WHERE SIGNIFICANT WINTER
WEATHER WILL OCCUR...JUST NOT BLIZZARD CONDITIONS. HAVE ALSO
ISSUED A HIGH WIND WARNING FOR THE UPPER KUSKOKWIM VALLEY NEAR THE
ALASKA RANGE AS WIND GUSTS TO 75 MPH ARE LIKELY THROUGH TONIGHT.
THE WIND HAS EVEN PICKED UP IN MCGRATH WITH GUSTS TO AROUND 35
MPH.

INTERIOR...AN UPPER RIDGE WILL CONTINUE TO BUILD ALONG THE ALCAN
BORDER INTO TUESDAY AS A DEEP LOW PERSISTS IN THE BERING SEA.  THIS
WILL CONTINUE THE MODERATE TO STRONG CHINOOK FLOW. THE 850 MB TEMP
AT PAFA HAS WARMED A REMARKABLE 25C THIS WEEKEND SETTING UP STRONG
LOW LEVEL INVERSIONS.  TEMPS ON THE HIGHER PEAKS AROUND FAIRBANKS
ARE NOW WELL INTO THE 20S WHILE THE VALLEYS LAG WELL BEHIND...AND
MOST LOW ELEVATION SITES ARE STILL WELL BELOW ZERO.  THIS WILL
CONTINUE TO MAKE THE TEMPERATURE FORECAST A CHALLENGE FOR THE NEXT
FEW DAYS.  THE MODELS CONTINUE TO BRING 850 MB TEMPS ABOVE 0C TO
AREAS DOWNWIND OF THE AK RANGE...WHICH SEEMS VERY REASONABLE IN
LIGHT OF THE STRONG CHINOOK FLOW. EXPECT THE HIGHER SUMMITS AND
AK RANGE PASSES TO HAVE TEMPS ABOVE FREEZING BY THIS AFTERNOON.
TEMPS ON THE YUKON FLATS AND ACROSS THE UPPER TANANA VALLEY WILL
LAG WELL BEHIND AND WILL REMAIN WELL BELOW ZERO.

THE OTHER CONCERN IS FOR VERY STRONG WIND AT ANTLER CREEK ALONG
THE PARKS HIGHWAY. BASED ON THE FACT THAT HEALY HAS HAD SOME GUSTS
OVER 50 MPH OVERNIGHT IT IS VERY LIKELY THAT ANTLER CREEK HAS
WARNING CRITERIA WINDS...AND UPGRADED THE ADVISORY TO A WARNING
EARLIER ON SHIFT. THE HIGH WINDS WILL LIKELY PERSIST INTO TUESDAY.
HAVE ALSO ISSUED A WIND ADVISORY FOR THE PASSES WEST OF THE TOK
CUTOFF IN THE EASTERN ALASKA RANGE. THE WARMER TEMPS SHOULD AT
LEAST MITIGATE SIGNIFICANT BLOWING SNOW CONCERNS. THE WIND ALONG
THE DALTON HIGHWAY SUMMITS HAS BEEN STRONG OVERNIGHT WITH GUSTS TO
45 MPH AT GOBBLERS KNOB. GIVEN THAT BETTLES PICKED UP ABOUT 8
INCHES OF FRESH SNOW EARLIER THIS WEEKEND HAVE ISSUED A WINTER
WEATHER ADVISORY FOR THE DALTON HIGHWAY SUMMITS IN ZONE 219 FOR
SIGNIFICANT BLOWING AND DRIFTING SNOW.

NORTH SLOPE...ABOVE AVERAGE TEMPS EXPECTED ALONG THE NORTH SLOPE
THROUGH MID WEEK. MOST OF THE AREA WILL HAVE DRY WEATHER.  THE
FRONTAL BOUNDARY ASSOCIATED WITH THE LOW IN THE BERING SEA WILL
BRING SNOW TO PARTS OF THE WESTERN BROOKS RANGE AND WESTERN ARCTIC
COAST TODAY AND TONIGHT. THERE WILL LIKELY BE SOME STRONG WIND
AND BLOWING SNOW TODAY INTO TONIGHT ACROSS THE HIGHER ELEVATIONS
OF THE WESTERN BROOKS RANGE AND HAVE ISSUED A WINTER WEATHER
ADVISORY FOR THE WESTERN BROOKS RANGE. WILL NEED TO KEEP A CLOSE
EYE ON THE VISIBILITIES ACROSS THE REMAINDER OF THE ARCTIC COAST
TODAY INTO TONIGHT FOR POSSIBLE BLOWING SNOW CONCERNS. LATEST
REPORTS FROM BARROW INDICATE THAT MOST OF THE SNOW HAS BECOME HARD
PACKED AND BLIZZARD CONDITIONS ARE UNLIKELY TO OCCUR UNLESS SOME
OF THE SNOW ALONG THE WESTERN ARCTIC COAST SPREADS FURTHER EAST
THAN EXPECTED.

COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FOR AKZ226.

HIGH WIND WARNING FOR AKZ225-AKZ227.

WINTER STORM WARNING FOR AKZ212-AKZ214-AKZ215-AKZ216.

BLIZZARD WARNING FOR AKZ207-AKZ209-AKZ210-AKZ211-AKZ213.

WINTER WEATHER ADVISORY FOR AKZ205-AKZ208-AK217-AKZ219.

GALE WARNING FOR PKZ200-PKZ210-PKZ215-PKZ220-PKZ245.

BRISK WIND ADVISORY FOR PKZ225-PKZ230-PKZ235-PKZ240-PKZ245.
&&

CB DEC 09