Blizzard and High Wind in Alaska, December 28 to 30, 2015

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
454 AM AKST MON DEC 28 2015

.DISCUSSION...
CURRENT MODEL RUNS CONTINUE TO INDICATE AN ACTIVE AND PROGRESSIVE
SOUTHERLY FLOW PATTERN OVER NORTHERN ALASKA THROUGH THURSDAY AS
SEVERAL UPPER LEVEL RIDGES AND TROUGHS MOVE ACROSS THE FORECAST
AREA. THE SOUTHERLY FLOW PATTERN WILL BRING MUCH ABOVE NORMAL
TEMPERATURES OVER ALL OF NORTHERN ALASKA AND TWO STRONG CHINOOK
WIND EVENTS TO THE ALASKA RANGE AND THE DELTA JUNCTION AREA.

UPPER AIR...
A RIDGE ALOFT CURRENTLY EXTENDS FROM THE BERING STRAIT TO NEAR
YAKUTAT AND SOUTHEASTWARD. THE RIDGE WILL MOVE NORTHEASTWARD AND
DAMPEN OUT OVER THE YUKON TERRITORY BY LATE TONIGHT. A SHORT WAVE
TROUGH CURRENTLY EXTENDS FROM BRISTOL BAY TO THE EASTERN
ALASKA PENINSULA THEN SOUTH SOUTHEASTWARD INTO THE GULF OF ALASKA.
THIS FEATURE WILL DAMPEN OUT IN AMPLITUDE CONSIDERABLE AS IT MOVES
TO A LINE NORTON SOUND-FAIRBANKS-NORTHWAY AND SOUTHEASTWARD BY
LATE THIS EVENING. STRONG SOUTHERLY FLOW ALOFT ACROSS THE ALASKA
RANGE WILL CONTINUE THROUGH THIS AFTERNOON.

UPPER LEVEL RIDGING WILL BEGIN TO REBUILD OVER THE CENTRAL AND
EASTERN PARTS OF NORTHERN ALASKA TUESDAY MORNING WHILE STRONG
SOUTHERLY FLOW DEVELOPS OVER THE WEST COAST AND WESTERN INTERIOR.
THE RIDGE AXIS WILL MOVE NORTHEASTWARD TO LINE POINT LAY-OLD CROW-
SOUTHEASTWARD INTO CANADA BY WEDNESDAY EVENING. ANOTHER SHORT
WAVE TROUGH WILL FOLLOW THE RIDGE...MOVING NORTHWARD ACROSS THE
ALASKA MAINLAND WEDNESDAY INTO WEDNESDAY EVENING. ANOTHER SURGE OF
STRONG SOUTHERLY WINDS ALOFT ACROSS THE INTERIOR WILL DEVELOP
TUESDAY NIGHT AND CONTINUE THROUGH WEDNESDAY.

OUT WEST...AN UPPER LEVEL TROUGH OVER THE SOUTHERN BERING SEA
WILL MOVE NORTHWARD TO A LINE ST MATTHEW ISLAND-WESTERN SEWARD
PENINSULA AND EASTWARD INTO THE INTERIOR BY THIS EVENING...FOLLOWED
CLOSELY BY A SECOND TROUGH WHICH MOVE NORTHWARD TO A LINE ST
MATTHEW ISLAND-WESTERN SEWARD PENINSULA BY TUESDAY MORNING. AN
UPPER LOW SOUTH OF THE CENTRAL ALEUTIANS NEAR 50N/178W WILL MOVE
TO NEAR THE PRIBILOF ISLANDS BY TUESDAY MORNING AND TO ABOUT 150
MILES WEST OF ST MATTHEW ISLAND BY LATE TUESDAY NIGHT.

ANOTHER STRONG IMPULSE WILL MOVE NORTHWESTWARD OUT OF THE
GULF OF ALASKA TO THE ALASKA PENINSULA LATE TUESDAY NIGHT AND
EXTEND FROM ST LAWRENCE ISLAND NORTHEASTWARD ACROSS THE WESTERN
SEWARD PENINSULA AND INTO THE SOUTHERN CHUKCHI SEA BY WEDNESDAY
EVENING. CURRENT GFS/NAM/CANADIAN MODELS ARE IN FAIRLY GOOD
AGREEMENT ON THIS FEATURE...ECMWF IS SLIGHTLY SLOWER WITH THE
MOVEMENT.

SURFACE...
WINDS ARE INCREASING IN THE WIND PRONE AREAS OF ZONES 223-225-226
AS THE FIRST OF TWO HIGH WIND EVENTS SPINS UP. WINDS ARE NOW
GUSTING TO OVER 60 MPH AT SOME OF THE FORT GREELY MESONET
SITES IN ZONE 226...MAXIMUM GUST OF 77 MPH REPORTED AT THE
TEXAS CONDO SITE. ANTLER CREEK IN THE RAILBELT ZONE HAS REPORTED
A MAX GUST OF 63 MPH. 700 MB WINDS ACROSS THE ALASKA WILL MAX OUT
AT AROUND 80 KT TODAY. WIND GUSTS TO 70 MPH ARE EXPECTED IN THE
WIND PRONE AREAS OF DENALI AND NEAR DELTA JUNCTION...WITH GUSTS TO
80 MPH IN AREAS NEAR THE RICHARDSON HIGHWAY IN THE EASTERN ALASKA
RANGE. CURRENT NAM12 CROSS SECTION ALONG THE RICHARDSON HIGHWAY
NEAR THE ALASKA RANGE INDICATES 700 MB WINDS MAXING OUT AT 80 KT
AND STRONG DESCENDING MOTION ALOFT...EXCEEDING 45 KT...WHICH
SHOULD MIX STRONG WINDS ALOFT DOWN TO THE SURFACE. DOWNWARD
VERTICAL VELOCITIES ARE SOMEWHAT LESS ALONG THE RAILBELT ROUTE
THROUGH DENALI. WINDY CONDITIONS WILL CONTINUE TONIGHT INTO
TUESDAY BUT REMAIN BELOW WARNING CRITERIA UNTIL THE SECOND HIGH
WIND EVENT BEGINS.

THE SECOND HIGH WIND EVENT WILL BE STRONGER AND HAS THE POTENTIAL
TO PRODUCE RECORD WIND GUSTS IN WIND PRONE AREAS NEAR THE ALASKA
RANGE AND IN THE DELTA JUNCTION AREA.

IN AREAS NEAR THE ALASKA RANGE IN THE LOWER KUSKOKWIM VALLEY...RECENT
RUNS OF THE NAM12 HAVE BEEN INDICATING 700 MB AND 800 MB WINDS
MAXING OUT AT OVER 100 KT...AND BOUNDARY LAYER WINDS MAXING OUT
AT 80-95 KT SOME AREAS. CROSS SECTIONS INDICATE STRONG DOWNWARD
VERTICAL VELOCITIES EXCEEDING 45 KT IN THE LEE OF THE RANGE WHICH
SHOULD MIX STRONG WINDS ALOFT DOWNWARD. WE ARE ANTICIPATING
MAXIMUM SURFACE WIND GUSTS TO 100 MPH IN WIND PRONE AREAS NEAR
THIS SECTION OF THE ALASKA RANGE. VERY STRONG WIND ARE EXPECTED
TO DEVELOP IN THIS AREA LATE TUESDAY EVENING AND CONTINUE THROUGH
WEDNESDAY.

IN DENALI...WINDS ALOFT ARE EXPECTED TO MAX OUT AT 80-95 KT
AT 700 MB AND 75-80 KT AT 800 MB...WITH STRONG DOWNWARD
VERTICAL VELOCITIES EXCEEDING 45 KT IN THE LEE OF THE ALASKA
RANGE CREST. WE ARE EXPECTING GUSTS TO 80 MPH IN WIND PRONE
AREAS ALONG THE RAILBELT ROUTE THROUGH DENALI. VERY STRONG WINDS
ARE EXPECTED TO DEVELOP AFTER MIDNIGHT TUESDAY NIGHT AND CONTINUE
THROUGH WEDNESDAY.

OVER THE EASTERN ALASKA RANGE...VERY STRONG WINDS ARE EXPECTED
TO REDEVELOP AFTER MIDNIGHT TUESDAY NIGHT AND CONTINUE THROUGH
WEDNESDAY. CURRENT NAM12 PROGS WINDS ALOFT BELOW 700 MB MAXING
OUT AT AS HIGH AS 100 KT OVER AREAS OF THE RICHARDSON HIGHWAY
SOUTH OF FORT GREELY...AND TO 80-85 KT OVER AREAS NORTHWARD
TO THE DELTA JUNCTION AREA. STRONG DOWNWARD VERTICAL VELOCITIES
EXCEEDING 45 KT ARE EXPECTED FROM NORTH OF THE ALASKA RANGE
TO ABOUT 15 MILES SOUTH OF FORT GREELY...WITH SOMEWHAT WEAKER
DOWNWARD VELOCITIES FARTHER NORTHWARD TO THE DELTA JUNCTION
AREA. THE STRONGEST WINDS ARE EXPECTED AROUND MID DAY WEDNESDAY.
WE ARE EXPECTING MAXIMUM GUSTS TO 100 MPH ALONG THE RICHARDSON
HIGHWAY IN THE EASTERN ALASKA RANGE...AND GUSTS TO 80 MPH IN AREAS
NEAR DELTA JUNCTION.

HIGH WIND WARNINGS ARE IN EFFECT FOR WIND PRONE AREAS IN
ZONES 223-225-226...WITH A HIGH WIND WATCH FOR ZONE 227. HIGH
WIND WATCHES OR WARNINGS FOR THE SECOND HIGH WIND EVENT IN ZONES
223-225-226 WILL BE ISSUED AT A LATER TIME.

OUT WEST...SEVERAL NORTHWARD MOVING TROUGHS AND SURFACE WEATHER
FRONTS WILL BRING PRECIPITATION TO THE WEST COAST...WESTERN
INTERIOR...AND SOUTHERN SLOPES OF THE CENTRAL AND WESTERN BROOKS
RANGE. PRECIPITATION IS EXPECTED TODAY ALONG THE WEST COAST
FROM THE SEWARD PENINSULA SOUTH...AND IN THE LOWER YUKON VALLEY...
MIDDLE YUKON AND LOWER KOYUKUK VALLEYS...AND AREAS OF THE LOWER
KUSKOKWIM VALLEY AWAY FROM THE ALASKA RANGE. PRECIPITATION WILL
SPREAD NORTHWARD TONIGHT AND CONTINUE THROUGH TUESDAY...AND
THROUGH TUESDAY NIGHT OVER THE WEST COAST...WESTERN PARTS OF THE
WESTERN INTERIOR...AND IN THE WESTERN BROOKS RANGE. WITH
SUBSTANTIALLY WARMER TEMPERATURES SPREADING NORTHWARD,,,THERE
WILL BE INCREASING POTENTIAL FOR MIXED PRECIPITATION INCLUDING
FREEZING RAIN. 1000-850 MB TEMPERATURES ARE PROGGED TO RISE
TO NEAR OR ABOVE FREEZING OVER MUCH OF THE NORTHERN ALASKA
FROM THE BROOKS RANGE SOUTHWARD.

FOR TODAY AND TONIGHT...SNOWFALL TOTALS UP TO ABOUT 6 INCHES ARE
EXPECTED IN ZONE 215...UP TO ABOUT 4 INCHES IN 214...1-4
INCHES OVER THE NORTHERN AND INTERIOR SEWARD PENINSULA...AND
ABOUT 4 INCHES ON THE SOUTHERN SEWARD PENINSULA COAST. SNOW
AMOUNTS MAINLY LESS THAN 2 INCHES ARE EXPECTED IN SOUTHERN
ZONES 207-208...209...216...217...AND WESTERN ZONE 219.
SEVERAL INCHES OF SNOW ARE EXPECTED IN ZONE 227 FROM MCGRATH
WEST.

NORTH TO NORTHEAST GALES WILL CONTINUE OVER ST LAWRENCE
ISLAND AND THE BERING STRAIT COAST THROUGH TONIGHT.

ABOVE NORMAL TEMPERATURES ARE EXPECTED TO CONTINUE OVER THE
NORTHERN ALASKA FORECAST AREA OUT THROUGH DAY 10.

COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WATCH FOR AKZ227.
HIGH WIND WARNING FOR AKZ223-AKZ225-AKZ226.
WINTER WEATHER ADVISORY FOR AKZ215.
GALE WARNING FOR PKZ210-PKZ225.
BRISK WIND ADVISORY FOR PKZ200-PKZ225.

&&

RF DEC 15