Area Forecast Discussion
Issued by NWS Fairbanks, AK

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FXAK69 PAFG 042231
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
131 PM AKST WED MAR 4 2015

.DISCUSSION...

MODELS...SHORT TERM AGREEMENT IS GOOD AND THEY INITIALIZED WELL
AGAINST THE 18Z SURFACE ANALYSIS. MODELS HAVE REVERTED BACK TO
NORMAL IN THE EXTENDED PERIODS WITH SIGNIFICANT DIVERGENCE BEYOND
90 HOURS OR SO. WILL CONTINUE TO USE A BLEND OF THE MODELS TO
NUDGE THE CURRENT DATABASE...BUT LEAN ON THE SREF TO INCREASE THE
SHORT TERM PRECIPITATION PROBABILITIES.

ALOFT...AT 500 HPA...RIDGING WITH 520 TO 540 HPA HAS MOVED OVER
THE INTERIOR TODAY AND WILL SLIDE EAST INTO CANADA TONIGHT AS THE
PROGRESSIVE PATTERN CONTINUES WITH FAIRLY ZONAL FLOW ACROSS THE
STATE. A 514 DAM LOW WILL MOVE TO THE WEST COAST TONIGHT WITH THE
LOW OVER THE BERING STRAIT AND SHORTWAVE EXTENDING SOUTH OVER
COLD BAY. THE LOW WILL MOVE OVER THE SEWARD PENINSULA BY THURSDAY
AFTERNOON WITH THE SHORTWAVE EXTENDING OVER CHIGNIK...THEN
CONTINUES EAST AS IT WEAKENS WITH THE LOW OVER THE ARCTIC PLAIN
AND THE SHORTWAVE WILL LIE FROM ANAKTUVUK PASS TO MANLEY HOT
SPRINGS TO HOMER BY FRIDAY MORNING. THE SHORTWAVE WILL EXIT THE
STATE BY FRIDAY AFTERNOON. A 534 DAM LOW IN THE GULF OF ALASKA
WILL MOVE TO YAKUTAT THIS EVENING AND PERSIST OVER THE AREA
THROUGH THURSDAY EVENING SPINNING SOME MOISTURE UP IN TO THE
EASTERN INTERIOR. WEAK RIDGING WILL BUILD IN BEHIND THE SHORTWAVE
WITH HEIGHTS RISING LESS THAN 10 DAM OVER MOST AREAS. THE LAST OF
THE MAJOR SHORTWAVES WILL MOVE TO THE WEST COAST LATE FRIDAY NIGHT
AND 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 QUICKLY
THROUGH THE FLOW. AT 850 HPA...WEAK COLD AIR ADVECTION WILL
CONTINUE THROUGH FRIDAY AS THE TEMPERATURES FALL 4 TO 8 DEGREES
CELSIUS. IN ADVANCE OF THE LAST MAJOR SHORTWAVE SOME WEAK WAR AIR
ADVECTION OF 2 TO 4 DEGREES WILL OCCUR. STRONG COLD AIR ADVECTION
WILL OCCUR STARTING SATURDAY WITH TEMPERATURES FALLING 10 TO 15
DEGREES CELSIUS. IN ADVANCE OF THE THIRD SHORTWAVE STRONG
SOUTHWEST FLOW OF 30 TO 55 KTS DEVELOPS WHICH WILL PULL IN
MOISTURE FROM THE BERING SEA.

SURFACE...A BROAD AREA OF LOW PRESSURE REMAINS OVER THE STATE
WITH A WEAK FRONTAL SYSTEM OVER THE UPPER YUKON FLATS. HIGH
PRESSURE WILL CONTINUE TO BUILD OVER THE ARCTIC COAST TONIGHT. AS
THE NEXT LOW PRESSURE SYSTEM MOVES TO THE WEST COAST IT WILL MERGE
WITH THE TROUGH OF OVER THE FLATS WITH A 1006 MB LOW DEVELOPING
OVER THE LIVENGOOD AREA BY THURSDAY MORNING. THE LOW WILL THEN
MOVE NORTHEAST TO BE OVER THE UPPER YUKON FLATS BY THURSDAY
EVENING THEN OVER THE NORTHERN YUKON TERRITORY BY FRIDAY MORNING.
A TROUGH WILL PERSIST OVER THE MIDDLE YUKON VALLEY AND YUKON FLATS
BEHIND THE LOW. THE NEXT LOW MOVES TO THE CENTRAL BERING SEA BY
FRIDAY MORNING WITH THE FRONT REACHING THE COAST SOON AFTER. THE
FRONT WILL LIE FROM THE BERING STRAIT TO GOLOVIN TO ST MARYS TO
KIPNUK BY FRIDAY AFTERNOON...THEN FRONT POINT HOPE TO AMBLER TO
KALTAG TO BETHEL BY SATURDAY MORNING. THE FRONT THEN GETS LOST IN
THE BROAD LOW PRESSURE PATTERN THAT DEVELOPS OVER THE STATE
SATURDAY. COLD AIR WILL ADVECT INTO THE WEST COAST SUNDAY MORNING
BEHIND THE LOW AND EVENTUALLY COVER THE FORECAST AREA BY MONDAY
MORNING.

ARCTIC COAST AND BROOKS RANGE...A RELATIVELY QUIET PERIOD
DEVELOPING OVER THE ARCTIC COAST WITH THE SYSTEMS MOVING ACROSS
THE CENTRAL PART OF THE STATE AND RIDGING BUILDING SOUTHEAST TO
THE BROOKS RANGE. STILL EXPECT MOSTLY CLOUDY CONDITIONS AND
STEADY TO COOLING TEMPERATURES NEXT 48 HOURS. SLIGHT WARMING ON
SATURDAY AS FRONTAL SYSTEM MOVES OVER THE BROOKS RANGE...BUT
TEMPERATURES WILL COOL SIGNIFICANTLY ON SUNDAY AS COLD ARCTIC AIR
PUSHES SOUTH OVER THE AREA. EXPECT SOME WINDS IN THE BROOKS RANGE
FRIDAY NIGHT INTO SATURDAY MORNING THAT WILL CREATE SOME
VISIBILITY ISSUES IN BLOWING SNOW AND MAY ENHANCE AVALANCHE
POTENTIAL AS THE SNOW IN THE PASSES GETS BLOWN AROUND.

WEST COAST AND WESTERN INTERIOR...WEAK SURFACE TROUGH REMAINS IN
THE MIDDLE YUKON VALLEY AND NEXT WEATHER FRONT IS MOVING TO THE
COAST TONIGHT. PERIODS OF SNOW DEVELOPING ACROSS THE AREA AS THE
EVENING PROGRESSES. SNOWFALL AMOUNTS WILL RANGE FROM 1 TO 4 INCHES
WITH THE HEAVIEST SNOW IN THE NULATO HILLS AND KUSKOKWIM
MOUNTAINS. THE NEXT FRONT ON SATURDAY WILL SPREAD ANOTHER 1 TO 5
INCHES ACROSS THE AREA. WINDS GENERALLY LIGHT. TEMPERATURES FLAT
NEXT COUPLE DAYS WITH THE EXCEPTION OF SOME SLIGHT WARMING IN
ADVANCE OF THE FRONT THAT MOVES INTO THE AREA FRIDAY. COOLING
BEGINS SATURDAY OVER THE AREA FROM THE NORTHWEST AND TEMPERATURES
WILL FALL 15 TO 25 DEGREES BY SUNDAY OVER MOST OF THE AREA.

CENTRAL AND EASTERN INTERIOR...WEAK TROUGH OF LOW PRESSURE OVER
THE YUKON FLATS WILL PERSIST AND LOW MOVING OVER THE WEST COAST
WILL MERGE WITH IT OVER LIVENGOOD. CLOUDS INCREASING THROUGH THE
EVENING WITH SNOW SPREADING BACK OVER THE AREA TONIGHT. SNOWFALL
AMOUNTS WILL RANGE FROM 1 TO 3 INCHES WITH THE HEAVIEST AMOUNTS
OVER THE WHITE AND RAY MOUNTAINS. ANOTHER ROUND OF SNOW WILL BEGIN
SATURDAY MORNING AND CONTINUE ON AND OFF THROUGH MONDAY AFTERNOON.
TEMPERATURES WILL REMAIN MILD WITH SLIGHT WARMING SATURDAY THEN
COOLING INTO THE MIDDLE OF NEXT WEEK.

EXTENDED FORECAST...MUCH COOLER WITH CLEARING SKIES OVER MOST OF
THE FORECAST AREA BY THE MIDDLE OF NEXT WEEK.

SATELLITE...THE GOES MVFR/IFR/LIFR PRODUCTS SHOWING A LARGE AREA
OF MVFR OVER THE WEST COAST WESTERN INTERIOR...AND WITH THE WEAK
TROUGH OVER THE YUKON FLATS. COMBO PRODUCT OF SPORT 04/1900Z AND
NPP VIIRS 04/1840Z SHOWING A BAND OF STRATUS OFF THE ARCTIC COAST
ASSOCIATED WITH THE ARCTIC FRONT THAT APPEARS TO BE MOVING TO
TOWARD THE COAST AT THIS TIME. WILL KEEP AN EYE ON THIS AS MAY
HAVE TO UPDATE SOME OF THE AVIATION FORECAST FOR THE AREA.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...

NONE.

&&

$$

SDB MAR 15


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