Area Forecast Discussion
Issued by NWS Fairbanks, AK

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FXAK69 PAFG 030932
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
132 AM AKDT SUN MAY 3 2015

.DISCUSSION...

MODELS...IN GOOD AGREEMENT OUT TO AROUND 60 OURS. INITIALIZED
WELL AT 06Z. WILL JUST USE A BLEND OF THE MODELS TO NUDGE THE
CURRENT DATABASE.

ALOFT...552 DAM HIGH OVER SOUTHCENTRAL ALASKA WILL MOVE EAST TO
THE COPPER RIVER BASIN AND WEAKEN TO 552 DAM...THEN BE ABSORBED
BY A RIDGE OVER THE GULF OF ALASKA. A 542 DAM CLOSED LOW OVER THE
KUSKOKWIM DELTA WILL REMAIN QUASI STATIONARY OVER THE AREA
THROUGH MONDAY EVENING...THEN BE ABSORBED INTO A SHORTWAVE MOVING
EAST OVER THE BROOKS RANGE. A RIDGE OVER THE EASTERN BERING SEA
WILL SPIT WITH A 553 CENTER MOVING OVER ST LAWRENCE ISLAND BY
MONDAY MORNING...THEN SLIDES WEST. A 531 DAM LOW SOUTH OF THE GULF
OF ALASKA WILL CONTINUE EAST INTO CANADA. A 520 DAM LOW OVER THE
WESTERN ALEUTIANS WILL MOVE SLOWLY EAST TO BE 400 NM SOUTH OF
DUTCH HARBOR BY WEDNESDAY MORNING. AT 850 HPA...WARMER
TEMPERATURES OVER THE INTERIOR AS THE THERMAL TROUGH STRENGTHENS
TUESDAY. NOT MUCH CHANGE IN TEMPERATURES OVER THE COASTAL AREAS.

SURFACE...A 1028 MB HIGH OVER THE CHUKCHI SEA WILL DRIFT NORTH. A
1002 MB LOW IN THE NORTHWEST PACIFIC WILL MOVE EAST INTO CANADA.
A BENIGN WEATHER PATTERN WILL PERSIST OVER MAINLAND ALASKA DRIVEN
BY WHERE THE THERMAL TROUGH SETS UP. THE THERMAL TROUGH WILL
BECOME BETTER DEFINED AS IT STRENGTHENS OVER THE INTERIOR
TUESDAY. A 983 MB LOW NEAR ADAK WILL BE QUASI STATIONARY THROUGH
TUESDAY MORNING.

ARCTIC COAST AND BROOKS RANGE...CHASING STRATUS WILL BE THE
THEME...BUT WILL ONLY HAVE TO CHASE THE CHANGING HEIGHT...BECAUSE
IT IS NOT GOING ANYWHERE. SOME PATCHY DENSE FOG IN THE MORNINGS
EAST OF BARROW WILL ALSO HAVE TO BE DEALT WITH. A WEAK SHORTWAVE
MOVES TO THE EAST OF BARROW BY MONDAY MORNING AND MAY KICK OFF A
FEW SHOWERS OR FLURRIES OVER THE EASTERN ARCTIC COAST AND EASTERN
BROOKS RANGE MONDAY AND TUESDAY. WINDS GENERALLY LESS THAN 10
MPH. WIND DIRECTION WILL BE WEST TO NORTHWEST TO THE WEST OF
PRUDHOE BAY AND SOUTHEAST TO EAST TO THE EAST OF PRUDHOE BAY.
MODIS 24HR MICROPHYSICS FROM SPORT SHOWS A BAND OF STRATUS AND
FOG THAT HAS MOVED INLAND OVER THE COASTAL AREAS...AS WELL AS
SOME STRATUS OVER THE EASTERN BROOKS RANGE.

WEST COAST AND WESTERN INTERIOR...SHOWERS OVER THE LOWER YUKON
DELTA WILL PERSIST UNTIL THE UPPER LEVEL LOW WEAKENS AND IS
ABSORBED BY SHORTWAVE OVER BROOKS RANGE MONDAY. OFFSHORE FLOW
WILL PERSIST OVER MOST OF THE AREA THROUGH TUESDAY WITH WINDS
GENERALLY LESS THAN 15 MPH. THERMAL TROUGH DEVELOPING BY TUESDAY
OVER THE LOWER YUKON AND KUSKOKWIM DELTAS WILL BRING SHOWERS TO
THE AREA DURING THE AFTERNOON TUESDAY. A RAPIDLY MOVING LOW IN
THE NORTH PACIFIC WILL MOVE NORTH ACROSS THE LOWER YUKON DELTA
INTO THE BERING STRAIT ON THURSDAY. NOT MUCH CHANGE IN
TEMPERATURE EXPECTED.

CENTRAL AND EASTERN INTERIOR...DEVELOPMENT OF THE THERMAL TROUGH
AS WE GET INTO THE WEEK WILL BE THE DRIVER FOR WEATHER IN THE
INTERIOR. DEWPOINTS WILL BE ON THE RISE AFTER ONE LAST DRY DAY
AND THIS WILL HELP INJECT MOISTURE INTO THE INTERIOR CREATING A
BETTER CHANCE OF AFTERNOON SHOWER DEVELOPMENT TUESDAY AND
WEDNESDAY. GENERALLY LIGHT EAST WINDS IN THE INTERIOR...HOWEVER
EXPECT SOME GUSTY WINDS IN THE AFTERNOON WHEN THE THERMAL TROUGH
SETS UP.

EXTENDED FORECAST FOR DAYS 5 TO 8...RIDGING FROM CANADA WILL BE
PUSHED BACK TO THE EAST AND LINGER OVER THE ALCAN BORDER AREA. A
LONG WAVE TROUGH WILL REMAIN OVER THE EASTERN BERING SEA AND
NORTHWEST ARCTIC. THERMAL TROUGH OVER THE INTERIOR WILL PERSIST
IN SOME FORM.

&&

.FIRE WEATHER...THERMAL TROUGH STRENGTHENS A LITTLE TODAY AND
WITH DEWPOINTS ON THE RISE AS WELL AS RELATIVE HUMIDITY CHANCE OF
SHOWERS INCREASES FOR TUESDAY AND WEDNESDAY. STILL NOT UNSTABLE
ENOUGH FOR ANY TYPE OF CONVECTIVE OUTBREAK...BUT WOULD NOT BE
SURPRISED BY AN ISOLATED THUNDERSTORM. NO SIGNIFICANT WINDS
EXPECTED. FAIR OVERNIGHT RECOVERY TONIGHT THEN GOOD RECOVERY THE
REMAINDER OF THE WEEK.

&&

.HYDROLOGY...SLOW BREAKUP CONTINUES...BUT THAT CAN CHANGE RAPIDLY.
OBSERVERS AND SPOTTERS CONTINUE TO WATCH THE YUKON RIVER AND WILL
BE FLYING RIVER WATCH MISSIONS OVER THE UPPER YUKON AROUND EAGLE
AGAIN TODAY.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...

NONE.

&&

$$

SDB MAY 15



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