Blizzard Watch 4, NWS Fairbanks, AK

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
103 PM AKST WED NOV 20 2013

.DISCUSSION...

MODELS...GOOD RUN TO RUN CONSISTENCY THE LAST COUPLE DAYS AND THEY
REMAIN IN GOOD AGREEMENT IN THE SHORT TERM ON THE BIG PICTURE
ISSUES. GFS CONTINUES TO HAVE PROBLEMS IN THE DETAILS...ESPECIALLY
THE TEMPERATURES. THERE ARE ALSO SOME FAIRLY BIG DIFFERENCES IN
THE MODELS IN THE SURFACE TO BOUNDARY LAYER WINDS. WILL LEAN ON
THE NAM FOR TEMPERATURES AND WINDS IN THE SHORT TERM. IN THE MID
AND EXTENDED PERIODS THEY SHOW FAIRLY SIGNIFICANT DIFFERENCES SO
THINK A BLEND IS THE BEST WAY TO GO AT THIS TIME.

ALOFT...AT 500 HPA...531 DAM HIGH CENTER OVER POINT HOPE WILL BE
QUASI STATIONARY OVER THE NORTHWEST COAST THROUGH FRI MORNING AS
IT WEAKENS TO 525 DAM...THEN IS ABSORBED INTO THE RIDGE OVER THE
EASTERN ARCTIC. A BRANCH OF THE RIDGE IN THE PACIFIC IS ROTATING
NORTHEAST OVER THE SOUTHEAST INTERIOR TONIGHT AND WILL BUILD
NORTH THU AND FRI AS IT SLIDES EAST OVER THE YUKON TERRITORY.
TROUGH OVER THE SOUTHERN HALF OF THE MAINLAND WILL SEE A 516 DAM
LOW DEVELOP OVER THE SOUTHCENTRAL AREA STRENGTHENING TO 511 DAM BY
THU MORNING AS IT CLOSES UP AND MOVES OVER NUNIVAK ISLAND...THEN
REMAINS QUASI STATIONARY AS IT STRENGTHENS TO 499 DAM BY FRIDAY
MORNING. THE LOW WILL THEN MOVE SLOWLY NORTHEAST AS IT WEAKENS AND
MOVES TO MACKENZIE BAY BY SUN NIGHT. AT 850 HPA...WEAK WARM AIR
ADVECTION ON THE WEST COAST...COLD AIR WILL HANG IN OVER THE
SOUTHEAST INTERIOR THROUGH THURSDAY EVENING BEFORE WARM AIR
ADVECTION BEGINS IN ERNEST. ALL THE MODELS ARE NOW SHOWING A BLOB
OF ABOVE ZERO AIR WORKING OVER THE ALASKA RANGE INTO THE INTERIOR
FOR FRIDAY...THEN WEAK COOLING FOR A COUPLE DAYS.

SURFACE...RIDGING OVER THE INTERIOR WILL HOLD THROUGH THU WHEN A
FRONTAL SYSTEM ASSOCIATED WITH A LOW OVER KODIAK ISLAND WILL SWING
NORTH AND THE GRADIENT BETWEEN THE RIDGE TO THE EAST AND THE LOW
TO THE SOUTHWEST INCREASES. THE FRONT WILL MOVE TO THE COAST BY
THURSDAY AFTERNOON PUSHING NORTH ACROSS THE ALASKA RANGE IN OVER
THE CENTRAL INTERIOR BY FRI MORNING. THE FRONT WILL CONTINUE TO
ROTATE TO THE NORTHWEST AND EXTEND FROM THE KUSKOKWIM DELTA TO
MACKENZIE BAY BY LATE FRI NIGHT. HIGHEST QPF VALUES WILL BE OVER
THE SOUTHWEST INTERIOR. MODELS ARE CONFLICTED ON AMOUNTS SO WILL
USE THE NAM AS THE BASE WHICH SHOWS A QUARTER TO OVER HALF AN INCH
FOR THE NULATO HILLS...THIS WILL TRANSLATE INTO 6 INCHES OR MORE
OF SNOW FOR SOME OF THOSE AREAS. A SPIN OFF LOW WILL FILL AND MOVE
NORTHEAST...THIS WILL KICK OFF SOME SNOW OVER THE INTERIOR BUT FOR
MOST AREAS LESS THAN 2 INCHES. THE MAIN LOW WILL FILL AND BE
ABSORBED BY A LOW IN THE NORTH PACIFIC BY SUNDAY MORNING. THIS
WILL LEAVE WEAK HIGH PRESSURE OVER THE AREA THAT WILL PERSIST INTO
NEXT WEEK.

ARCTIC COAST...STRONG WINDS CONTINUE IN THE EAST BUT WILL TAPER
OFF LATER THIS EVENING. CLEARING ACROSS THE AREA AS RIDGE MOVES
OVER THE AREA TONIGHT. THIS WILL NOT PREVENT STRATUS ALONG THE
COAST...ESPECIALLY NEAR ANY OPEN WATER.

WEST COAST AND WESTERN INTERIOR...MOSTLY CLEAR TONIGHT ACROSS THE
AREA WITH OFFSHORE FLOW ALONG THE COAST AND LIGHT WINDS INLAND.
CLOUDS AND SNOW MOVING NORTH INTO THE AREA BY THU AFTERNOON. WILL
ISSUE WINTER WEATHER WATCHES FOR HEAVY SNOW IN ZONES 212...214...215
AND 216...MAINLY ALONG THE NULATO HILLS...FOR SNOW ACCUMULATIONS
OF 6 TO 12 INCHES ON FRIDAY. FRONTAL SYSTEM WILL BRING IN SOME
STRONGER WINDS JUST OFF THE SURFACE...SO WINDS GUSTING TO 45 MPH
NEAR THE ALASKA RANGE AND IN THE NULATO HILLS BEGINNING THURSDAY
AFTERNOON COULD TRIGGER SOME BLOWING SNOW ISSUES. LOW MOVES OUT
SAT SO LOOK FOR CLEARING AS WEAK RIDGE BUILDS OVER AND OFFSHORE
FLOW RETURNS ALONG THE COAST.

INTERIOR...COLD WILL HANG IN THROUGH THU MORNING...THEN WARM AIR
ADVECTION IN ADVANCE OF THE FRONT MOVING NORTH OUT OF THE GULF.
MOST PRECIPITATION WILL BE SHADOWED OUT FRI FROM FAIRBANKS SOUTH
BUT AS THE WEEKEND PROGRESSES MOST LOCATIONS WILL GET SOME SNOW
THOUGH AN INCH OR LESS WILL BE COMMON...THE EXCEPTION WILL BE
ALONG THE ALASKA RANGE WITH HEAVY SNOW BEGINNING LATE THU THROUGH
FRI...SO WILL ISSUE WINTER WEATHER WATCHES FOR ZONES 225 AND 226.
WINDS PICKING UP ALOFT AS THE FRONT MOVES NORTH WILL BRING BLOWING
SNOW ISSUES TO HIGHER ELEVATIONS AND SOME VALLEY LOCALS AS WINDS
GUSTING TO 45 MPH DEVELOP THU AND PERSIST INTO FRI. WITH GAP WINDS
DEVELOPING THROUGH THE ALASKA RANGE THU NIGHT TEMPERATURES WILL
JUMP 40 TO 60 DEGREES IN SOME LOCATIONS WITH HIGHS REACHING THE
TEENS IN SOME AREAS FRI AFTERNOON.

&&

COASTAL HAZARD POTENTIAL DAYS 3 AND 4...POTENTIAL FOR SOME HIGH
SURF ON THE NORTH SIDE OF ST LAWRENCE ISLAND FRI MORNING THROUGH
SAT.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY FOR AKZ223.

WINTER WEATHER ADVISORY FOR AKZ219-AKZ220-AKZ221-AKZ222.

WINTER STORM WATCH FOR AKZ212-AKZ214-AKZ215-AKZ216-AKZ225-AKZ226.

HEAVY FREEZING SPRAY WARNING FOR PKZ200-PKZ210-PKZ220-PKZ225.
&&

SDB NOV 13