Blizzard in Alaska, March 3 to 4, 2015

NORTHERN ALASKA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE FAIRBANKS AK
108 PM AKST TUE MAR 3 2015

.DISCUSSION...

MODELS...AGREEMENT IN THE MODELS CONTINUES TO BE VERY GOOD INTO
THE EXTENDED PERIODS. THE 12Z RUNS OF THE GFS AND ECMWF
INITIALIZED WELL AGAINST THE 18Z SURFACE ANALYSIS. WINDS APPEAR TO
BE A LITTLE LIGHTER THAN THE PREVIOUS RUNS AND TEMPERATURES ARE A
LITTLE WARMER...BUT NOT SIGNIFICANTLY...SO WILL JUST NUDGE THE
CURRENT GRIDS WITH A 50/50 BLEND OF THE LATEST MODELS.

ALOFT...AT 500 HPA...RIDGING WITH 540 TO 550 HPA HEIGHTS OVER THE
EASTERN HALF OF THE STATE CONTINUES TO BREAK DOWN AS SERIES OF
SHORTWAVES MOVE OVER AND THROUGH THE RIDGE. THE FIRST SHORTWAVE
LIES FROM OVER THE WESTERN ARCTIC TO POINT LAY TO BETHEL THIS
AFTERNOON AND WILL MOVE TO LIE FROM THE CENTRAL ARCTIC TO
KAKTOVIK TO COOK INLET WEDNESDAY MORNING...EVENTUALLY DRAGGING
EAST OUT OF THE SOUTHEAST INTERIOR BY WEDNESDAY AFTERNOON. WEAKER
RIDGING WITH HEIGHTS OF 520 TO 540 HPA WILL MOVE IN BEHIND THE
SHORTWAVE WEDNESDAY NIGHT. THE NEXT SHORTWAVE MOVES OVER THE WEST
COAST THURSDAY MORNING AND WILL LIE FROM THE CHUKCHI SEA TO
KOTZEBUE SOUND TO CHIGNIK THURSDAY AFTERNOON...THEN FROM BARROW TO
TANANA TO KODIAK BY FRIDAY MORNING...AND FROM KAKTOVIK TO DOT LAKE
TO CORDOVA BY FRIDAY AFTERNOON BEFORE EXITING THE STATE FRIDAY
EVENING. FLOW THROUGH THIS PERIOD WILL BECOME MORE ZONAL AND SOME
VERY WEAK RIDGING WILL MOVE ACROSS THE AREA BEHIND THE SECOND
SHORTWAVE SO NOT EXPECTING MUCH CLEARING BEHIND THE SHORTWAVE. THE
THIRD IN THE SERIES OF SHORTWAVES APPEARS TO BE THE STRONGEST AND
WILL MOVE TO THE WEST COAST FRIDAY EVENING AND BY SATURDAY MORNING
WILL LIE FROM THE BERING STRAIT TO MARSHALL TO COLD BAY...THEN
FROM POINT HOPE TO KALTAG TO CHIGNIK BY SATURDAY AFTERNOON...THE
SHORTWAVE WILL BE LOST IN THE FLOW AS THE TROUGH BECOMES VERY
BROAD ACROSS THE STATE WITH MINOR SHORTWAVES MOVING THROUGH THE
FLOW. AT 850 HPA...WEAK COLD AIR ADVECTION WILL CONTINUE THROUGH
FRIDAY BEHIND THE SECOND SHORT WAVE WHEN WE SEE A COUPLE DEGREES
OF WARMING...THEN SOME STRONG COLD AIR ADVECTION BEHIND THE THIRD
SHORTWAVE WHEN WE WILL SEE TEMPERATURES FALL 10 TO 15 DEGREES
CELSIUS IN MOST AREAS. IN ADVANCE OF THE THIRD SHORTWAVE STRONG
SOUTHWEST FLOW OF 30 TO 50 KTS DEVELOPS WHICH WILL PULL IN
MOISTURE FROM THE BERING SEA.

SURFACE...A COMPLEX LOW PRESSURE SYSTEM OVER THE WEST COAST WITH
SEVERAL CENTERS WILL BE WORKING EAST THIS EVENING...SOUTH OF THE
BROOKS RANGE THE SYSTEM WILL WEAKEN SIGNIFICANTLY AS IT PUSHES
THROUGH THE RIDGE. NORTH OF THE BROOKS RANGE THE LOW WILL
STRENGTHEN TO 998 MB AS IT MOVES TO 100 NM NORTH OF BARROW THIS
AFTERNOON..THEN MOVES NORTHEAST TO 250 NM NORTH OF DEADHORSE BY
WEDNESDAY MORNING AT 995MB...AND TO 250 NM NORTH OF DEMARCATION
POINT BY WEDNESDAY AFTERNOON AS IT WEAKENS SLIGHTLY TO 997 MB. AS
THE LOW BUMPS UP AGAINST THE RIDGE A FAIRLY STRONG GRADIENT WILL
DEVELOP OVER THE NORTHEAST ARCTIC COAST. THE FRONT WEAKENS
SIGNIFICANTLY OVER THE INTERIOR AS IT MOVES EAST AND RIDES OVER
AND THROUGH THE RIDGE...BUT WILL STILL PRODUCE SOME CLOUDS AND
SNOW THAT WILL PERSIST THROUGH THE WEEK. THE FRONT WILL LIE FROM
OLD CROW TO TANANA TO KALTAG WEDNESDAY EVENING WITH A 1007 MB LOW
IN THE UPPER YUKON FLATS...THEN FROM CHALKYTSIK TO MANLEY HOT
SPRINGS TO MCGRATH THURSDAY MORNING WITH A 1005 MB LOW NEAR
LIVENGOOD. AS THE NEXT SYSTEM APPROACHES THE COAST ON THURSDAY
EVENING IT WILL BE ABSORBED INTO THE SYSTEM WITH A 1008 MB LOW
REMAINING IN THE VICINITY OF LIVENGOOD AND THE FRONT REMAINING
FAIRLY STATIONARY. WEAK SOUTHWEST FLOW WILL PERSIST AT LOWER
LEVELS PROVIDING A GOOD MOISTURE SOURCE FOR SNOW DEVELOPMENT. AS
THE THIRD SYSTEM MAKES IT TO THE COAST ON FRIDAY NIGHT THE
SOUTHWEST FLOW INCREASES SIGNIFICANTLY ENHANCING THE MOISTURE INTO
THE SYSTEM.

ARCTIC COAST AND BROOKS RANGE...BLIZZARD WARNINGS AND WINTER
WEATHER ADVISORIES CONTINUE. LOW WILL BE MOVING EAST AND
NORTHEAST TONIGHT WITH STRENGTHENING WINDS. BLIZZARD FOR DEADHORSE
AND KAKTOVIK NOT AS SEVERE AS LAST ONE...BUT WINDS GUSTING NEAR
60 MPH WITH SUSTAINED WINDS IN THE 30 TO 40 MPH RANGE WITH SOME
LIGHT SNOW WILL CREATE PERIODS OF WHITEOUT CONDITIONS OVERNIGHT
AND INTO WEDNESDAY EVENING BEFORE THE WINDS DROP OFF. WINDS FOR
THE REMAINDER OF THE AREA WILL BE IN THE 15 TO 25 MPH RANGE WITH
POOR VISIBILITY IN BLOWING SNOW. TEMPERATURES MILD TONIGHT THEN A
COOLING TREND THAT WILL SEE TEMPERATURES FALL 10 TO 20 DEGREES
OVER THE NEXT COUPLE DAYS. AS WE GET INTO THE WEEKEND THE NEXT
SYSTEM WILL STAY SOUTH OF THE BROOKS RANGE...BUT EXPECT CLOUDY
CONDITIONS AND COOLING TEMPERATURES.

WEST COAST AND WESTERN INTERIOR...SLOW MOVING FRONT MAKING ITS WAY
THROUGH THE AREA THIS EVENING. AREA WILL SEE SOME CLEARING
OVERNIGHT ALONG THE COASTAL AREAS AS RIDGING MOVES TO THE COAST. A
1012 MB LOW DEVELOPS OVER THE MIDDLE YUKON THIS EVENING...SO IT
WILL KEEP CLOUDS AND LIGHT SNOW IN THE MIDDLE YUKON VALLEY EVEN AS
THE REMAINDER OF THE AREA SEES CLEARING. THE CLEARING WILL
CONTINUE INTO WEDNESDAY WHEN THE NEXT SYSTEM MAKES ITS WAY TO THE
COAST SPREADING ANOTHER ROUND OF SNOW TO THE COAST WEDNESDAY
EVENING AND INTO THE INTERIOR OVERNIGHT INTO THURSDAY MORNING.
CLOUDY CONDITIONS WILL PERSIST THROUGH THE WEEKEND WITH THE NEXT
MAJOR SNOW MAKER GETTING TO THE COAST FRIDAY AFTERNOON.
TEMPERATURES WILL BE ON A GENERAL COOLING TREND THROUGH THE WEEK.
WINDS WILL BE RELATIVELY LIGHT THROUGH THURSDAY THEN INCREASING
ALONG THE COAST ON FRIDAY.

CENTRAL AND EASTERN INTERIOR...SLOW MOVING FRONT WILL MAKE ITS WAY
INTO THE INTERIOR THROUGH THE EVENING SPREADING LIGHT SNOW TO ALL
AREAS. PERIODS OF SNOW WILL PERSIST AROUND THE INTERIOR INTO
FRIDAY BEFORE THE WEAK RIDGE PROVIDES FOR A LITTLE CLEARING. NOT
EXPECTING MUCH AS THE RIDGE IS PRETTY WEAK. WINDS WILL REMAIN
LIGHT ACROSS THE INTERIOR. TEMPERATURES WILL BE FLAT TO SLOWLY
FALLING AS WE GET A LITTLE BIT OF COLD AIR ADVECTION INTO THE
AREA. SNOWFALL AMOUNTS IN THE INTERIOR OF 1 TO 3 INCHES WILL BE
THE RULE THROUGH FRIDAY. HEAVIER SNOW IS EXPECTED ON THE WEEKEND
AS THE STRONGEST OF THE SHORTWAVES MOVES ACROSS THE STATE.

EXTENDED FORECAST FOR DAYS 6 AND 7...PROGRESSIVE PATTERN WITH
ZONAL FLOW IN THE UPPER LEVELS AND SOUTHWEST FLOW IN THE LOWER
LEVELS WILL CONTINUE INTO MONDAY THEN FLOW BECOMES NORTHWEST
AS RIDGE PARKS ITSELF OVER THE CENTRAL BERING SEA AND SHORTWAVES
MOVE DOWN THE WEST COAST AND WESTERN INTERIOR AROUND THE LONG WAVE
TROUGH THAT MOVES OVER THE ALCAN BORDER.

SATELLITE...THE GOES MVFR/IFR/LIFR PRODUCTS PROVIDING A GOOD FIRST
GUESS AS TO WHERE THE STRATUS AND FOG ARE AS THE SYSTEM MOVES
ACROSS THE STATE. IFR CONDITIONS LOOK TO BE SPOTTY AND
CONCENTRATED IN THE MIDDLE AND LOWER YUKON.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...

BLIZZARD WARNING FOR AKZ203-AKZ204.

WINTER WEATHER ADVISORY FOR AKZ201-AKZ202-AKZ205-AKZ206.

BRISK WIND ADVISORY FOR PKZ210-PKZ215-PKZ220-PKZ225-PKZ230-
PKZ235-PKZ240-PKZ245.

&&

SDB MAR 15