Winter Storm Warning 6, NWS Fairbanks, AK

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
147 PM AKST THU FEB 20 2014

.DISCUSSION...

MODELS...CONTINUE TO INITIALIZE WELL WITH GOOD RUN TO RUN
CONTINUITY IN THE NEAR TERM. MODELS ARE SIMILAR IN HANDLING THE
BUILDING BLOCKING HIGH THAT SETS UP OVER THE EASTERN INTERIOR OVER
THE NEXT 48 HOURS AND REMAINS ANCHORED OVER THE AREA THROUGH NEXT
WEEK. THEY ARE NOT DOING SO WELL WITH THE SHORTWAVES THAT MOVES UP
THE WESTERN FACE OF THE RIDGE BEGINNING EARLY NEXT WEEK.

ALOFT...AT 500 HPA...505 DAM CLOSED LOW OVER THE KENAI PENINSULA
WILL CONTINUE TO NORTHEAST AS IT IS ABSORBED INTO A LONGWAVE
TROUGH THAT WILL SLOWLY DRAG OUT OF THE EASTERN INTERIOR BY
SATURDAY AFTERNOON. RIDGING FROM THE NORTH PACIFIC CONTINUES TO
BUILD NORTH OVER SOUTHWEST ALASKA TODAY WITH A 537 DAM HIGH OVER
SIBERIA NEAR 66N 162E MOVING OVER THE NORTHWEST COAST BY LATE
FRIDAY...THEN MERGING WITH THE RIDGE BUILDING OVER SOUTHWEST
ALASKA. A CLOSED HIGH WILL BREAK OFF FROM THE RIDGE AND EVENTUALLY
SET UP OVER THE EASTERN INTERIOR SUNDAY WITH A 558 DAM CENTER. A
518 DAM LOW CENTER 600NM SOUTH OF ADAK WILL MOVE OVER ATKA ISLAND
BY FRIDAY AFTERNOON...THEN CONTINUE OVER THE CENTRAL BERING SEA BY
SATURDAY MORNING THEN MOVE EAST. A SHORTWAVE ASSOCIATED WITH THE
LOW WILL MOVE TO THE ALASKA PENINSULA FRIDAY NIGHT...TO NUNIVAK
ISLAND BY EARLY SATURDAY MORNING...AND TO THE SEWARD PENINSULA BY
SATURDAY AFTERNOON THEN CONTINUE TO MOVE NORTHWEST.

SURFACE...WEAK HIGH PRESSURE WILL PERSIST NORTH OF THE ALASKA
RANGE THROUGH FRIDAY THEN ANCHOR OVER THE EASTERN INTERIOR INTO
NEXT WEEK. LOW IN THE NORTH PACIFIC WILL MOVE TO ATKA ISLAND BY
FRIDAY MORNING AT 974MB...THEN CONTINUE INTO THE CENTRAL BERING
SEA BY SATURDAY MORNING AS IT STRENGTHENS TO 964MB...MOVING TO THE
EASTERN BERING SEA BY SUNDAY MORNING AT 970MB. ASSOCIATED FRONTAL
SYSTEM WILL MOVE TO THE ALASKA PENINSULA BY FRIDAY MORNING...TO ST
LAWRENCE ISLAND AND THE LOWER YUKON DELTA BY LATE FRIDAY
NIGHT...THEN CONTINUE TO DRAG UP THE COAST INTO SATURDAY AS IT
STALLS ALONG THE COAST FROM POINT HOPE EXTENDING SOUTH AS THE LOW
MOVES OVER CHUKOTKA. A WEAK LEESIDE TROUGH WILL DEVELOP NORTH OF
THE ALASKA RANGE SATURDAY AS CHINOOK FLOW DEVELOPS...STRONGEST
WINDS WILL BE IN THE WESTERN RANGE.

ARCTIC COAST...HIGH PRESSURE WILL REMAIN OVER THE ARCTIC COAST
THROUGH SATURDAY MORNING WITH WEAK OFFSHORE FLOW. BIG PATCH OF
STRATUS THAT WAS OVER THE OFFSHORE WATERS YESTERDAY...THAT WAS
SHOWING UP ON THE NPP VIIRS FOG PRODUCT SHOWS UP WELL AGAIN
TODAY...HAS MOVED SOUTH TO THE COAST AND WILL CONTINUE TO DRIFT
SOUTH TONIGHT. NOT EXPECTING ANY PRECIPITATION WITH THE STRATUS
BUT A FEW FLURRIES ARE POSSIBLE. THE STRATUS WILL MOVE OVER A GOOD
PORTION OF THE ARCTIC SLOPE AND WILL HELP MODERATE THE
TEMPERATURES A LITTLE BIT...SO EXPECT SLIGHTLY WARMER OVERNIGHT
LOWS. 850MB TEMPERATURES CONTINUE TO SHOW A SLOW WARM UP FOR THE
AREA BEGINNING TONIGHT. PATCHY FOG MAY DEVELOP AROUND THE
COMMUNITIES.

WEST COAST AND WESTERN INTERIOR...PRETTY QUIET TONIGHT. NEXT
SYSTEM MOVING TO THE LOWER YUKON DELTA AND ST LAWRENCE ISLAND LATE
FRIDAY NIGHT AND SATURDAY MORNING. EXPECT PRECIPITATION IT TO
START OUT AS SNOW BUT CHANGE TO MIXED RAIN AND SNOW BY LATE
SATURDAY SOUTH OF THE SEWARD PENINSULA. AS THE LOW PUSHES NORTH
FRIDAY STRONG OFFSHORE FLOW DEVELOPS. THE GALE FORCE WINDS
COMBINED WITH THE SNOW WILL CREATE NEAR WINTER STORM
CONDITIONS...SO WILL ISSUE A WINTER STORM WATCH FOR
Z211...Z212...Z213 AND Z214. A BAND OF STRATUS AND FOG SEEN IN THE
NPP VIIRS FOG PRODUCT IS ERODING...BUT CONTINUE TO IMPACT THE
BERING STRAIT COAST AND ST LAWRENCE ISLAND WITH STRATUS AND
FLURRIES. THIS BAND WILL CONTINUE TO ERODE AS IT MOVE TO THE WEST
OUT OF THE AREA IN ADVANCE OF THE FRONT. GEOCAT MODIS SHOWS SOME
IFR AND LIFR BUT IT IS OFFSHORE AROUND ST LAWRENCE ISLAND AND WILL
NOT IMPACT THE FORECAST AREA.

INTERIOR...PATCHES OF STRATUS FLOATING AROUND UNDER THE RIDGE OF
HIGH PRESSURE CAN BE SEEN ON THE NPP VIIRS FOG PRODUCT. EXPECT IT
TO CONTINUE TO FLOAT AROUND AS IT SLOWLY ERODES. THE GEOCAT MODIS
IMAGERY SHOWS NO AREAS OF LIFR OR IFR IN THE INTERIOR. LIGHT
WINDS WILL PREVAIL UNDER THE WEAK HIGH PRESSURE. NO SIGNIFICANT
PRECIPITATION THROUGH THE WEEKEND. MAINLY CLEAR SKIES WILL ALLOW
FOR MAXIMUM OVERNIGHT COOLING AND DAYTIME WARMING. CHINOOK FLOW
THROUGH THE ALASKA RANGE BEGINNING FRIDAY...EXPECT GUSTY WINDS
NEAR PASSES BUT NOT TO WARNING LEVELS.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FOR AKZ211-AKZ212-AKZ213-AKZ214.

BRISK WIND ADVISORY FOR PKZ210.
&&

SDB FEB 14