Area Forecast Discussion
Issued by NWS Fairbanks, AK

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000
FXAK69 PAFG 011308
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
508 AM AKDT TUE SEP 1 2015

.DISCUSSION...

UPPER AIR... TROUGH ALOFT EXTENDING FROM THE WESTERN BEAUFORT SEA
SOUTHEASTWARD TO MAYO WILL SHIFT EASTWARD...EXTENDING FROM 200
MILES NORTH OF BARROW TO INUVIK AND SOUTHEASTWARD BY LATE TONIGHT.
THE TROUGH WILL THEN MERGE WITH A SHORT WAVE TROUGH INCOMING FROM
THE WEST. THIS NEXT SHORT WAVE TROUGH EXTENDS FROM 200 MILES NORTH
OF WRANGEL ISLAND SOUTHWESTWARD TO THE RUSSIAN ARCTIC COAST...AND
WILL MOVE EASTWARD TO EXTEND FROM 80N/130W TO DEMARCATION POINT BY
LATE WEDNESDAY NIGHT. CURRENT GFS/NAM/ECMWF RUNS AND THE GEFS
ENSEMBLE MEAN ARE IN GOOD AGREEMENT ON THE MOVEMENT OF THIS NEXT
SHORT WAVE.

AN UPPER LEVEL RIDGE CURRENTLY EXTENDS FROM THE CHUKOTSK PENINSULA
TO THE EASTERN ALEUTIANS AND SOUTHWARD. THE SOUTHERN PART OF THE
RIDGE WILL MOVE EASTWARD BY LATE TONIGHT...WITH THE RIDGE AXIS
EXTENDING FROM THE CHUKOTSK PENINSULA TO UNALAKLEET THEN SOUTHWARD
INTO THE WESTERN GULF OF ALASKA. BY WEDNESDAY EVENING THE RIDGE
WILL SHIFT A BIT NORTHWARD AND EASTWARD...RIDGE AXIS EXTENDING
FROM CAPE SCHMIDT ON THE SIBERIAN COAST TO POINT LAY TO TANANA
THEN SOUTHWARD TO PRINCE WILLIAM SOUND. THE PORTION OF THE RIDGE
OVER NORTHERN ALASKA WILL REMAIN STATIONARY THROUGH THURSDAY
AFTERNOON. CURRENT MODEL RUNS AND THE GEFS ENSEMBLE MEAN SHOW
SIMILAR SOLUTIONS.

BY THURSDAY AFTERNOON...THE GFS/ECMWF/GEFS ENSEMBLE MEAN
SOLUTIONS SPLIT OFF AN UPPER LOW FROM THE EASTWARD MOVING SHORT
WAVE...WITH THE UPPER LOW CENTER PLACED NEAR OR JUST WEST OF THE
MACKENZIE RIVER DELTA. THE NAM SOLUTION RETAINS THE TROUGH WITH NO
LOW CENTER SPLITTING OFF.

OFF TO THE WEST...A LOW AMPLITUDE SHORT WAVE TROUGH MOVING UP THE
WEST SIDE OF THE RIDGE IS NOW OVER THE WESTERN ALEUTIANS AND WILL
MOVE NORTHEASTWARD TO ST LAWRENCE ISLAND AND NORTON SOUND BY
WEDNESDAY AFTERNOON...THEN DAMPENING OUT SOME AS IT MOVES TO THE
CHUKOTSK PENINSULA AND THE CHUKCHI SEA BY THURSDAY MORNING. THE
GFS/ECMWF SOLUTIONS ARE SIMILAR...THE NAM IS A LITTLE SLOWER ON
THE MOVEMENT OF THE SHORT WAVE...THIS FEATURE BECOMES SMOOTHED OUT
IN THE GEFS ENSEMBLE MEAN. THE SLIGHTLY FASTER GFS/ECMWF CONSENSUS
IS PREFERRED. A SURFACE LOW PRESSURE CENTER IS ASSOCIATED WITH
THIS SHORT WAVE.

SURFACE... A 1020 MB HIGH IS NOW CENTERED JUST EAST OF UMIAT WITH
A NARROW RIDGE EXTENDING EASTWARD ACROSS THE INTERIOR ARCTIC
SLOPE. THE HIGH WILL MOVE TO NEAR DEADHORSE BY THIS
AFTERNOON...WEAKENING THE SEA LEVEL PRESSURE GRADIENT OVER THE
EASTERN ARCTIC COAST. THIS WILL RESULT IN DECREASING WINDS ON THE
EASTERN ARCTIC COAST THIS AFTERNOON.

A NARROW HIGH PRESSURE RIDGE ACROSS THE ALASKA WEST COAST AND
THE ALASKA PENINSULA WILL MORPH INTO A BROAD 1020-1022 MB OVER
THE CENTRAL AND EASTERN INTERIOR BY THIS EVENING. THE HIGH WILL
BUILD TO A 1024 MB CENTER OVER THE LOWER MACKENZIE RIVER REGION
BY WEDNESDAY MORNING.

OUT WEST...A 1004 MB LOW CENTERED NEAR AMCHITKA WILL DEEPEN TO A
1001 MB LOW ABOUT 100 MILES WEST OF THE PRIBILOFS BY LATE THIS
AFTERNOON...THEN FILL BY 1-2 MB AS IT MOVES TO NEAR OR JUST
WEST OF ST LAWRENCE ISLAND BY WEDNESDAY AFTERNOON. THE OPERATIONAL
GFS AGREES WELL WITH THE GEFS ENSEMBLE MEAN...PUTTING THE CENTER
ABOUT 100 MILES WEST OF ST LAWRENCE ISLAND BY WEDNESDAY EVENING.
NAM AND ECMWF POSITIONS SLIGHTLY FARTHER TO THE EAST. A GFS/NAM/
ECMWF CONSENSUS WOULD PUT THE CENTER ABOUT 50 MILES WEST OF
GAMBELL WEDNESDAY EVENING. GFS/ECMWF MODEL RUNS FILL THE LOW OVER
THE GULF OF ANADYR BY LATE THURSDAY NIGHT AND LOOK LIKE A
REASONABLE SOLUTION.

ARCTIC COAST...
OVER THE EASTERN ARCTIC COAST...WEST WINDS 25-35 MPH GRADUALLY
DECREASING THIS AFTERNOON AND TONIGHT. ELSEWHERE ALONG THE ARCTIC
COAST... WINDS EXPECTED TO BE 15 MPH OR LESS THROUGH WEDNESDAY.
EAST WINDS 15-20 MPH DEVELOPING OVER ALL OF THE COAST THURSDAY.
EAST WINDS 25-30 MPH EXPECTED ALONG THE CENTRAL AND EASTERN ARCTIC
COAST THURSDAY NIGHT. SNOW AND BLOWING SNOW CONTINUING ALONG THE
EASTERN ARCTIC COAST THIS MORNING...ADDITIONAL SNOWFALL ABOUT 1
INCH EXPECTED. CHANCE OF RAIN AND SNOW THIS AFTERNOON OVER
THE EASTERN ARCTIC COAST.

BROOKS RANGE...
A CHANCE OF SNOW IN THE EASTERN BROOKS RANGE THIS MORNING...
OTHERWISE NO PRECIPITATION EXPECTED THROUGH THURSDAY.

CENTRAL AND EASTERN INTERIOR...
SPOTTY SHOWERS POSSIBLE IN THE ALASKA RANGE AND SOUTHEAST
INTERIOR TODAY...PRECIPITATION WILL BE SNOW IN THE ALASKA
RANGE. OTHERWISE...NO PRECIPITATION IS EXPECTED THROUGH
THURSDAY. DECREASING CLOUDS MOST AREAS TONIGHT WITH THE INCOMING
HIGH PRESSURE RIDGE. CLEAR OR PARTLY SKIES WEDNESDAY AND WEDNESDAY
NIGHT...WIDESPREAD FROST TONIGHT WITH LOW TEMPERATURES TONIGHT IN
THE MID 20S TO LOWER 30S.

WESTERN INTERIOR...
NO PRECIPITATION EXPECTED THROUGH WEDNESDAY. RAIN
LIKELY IN THE LOWER YUKON VALLEY WEDNESDAY NIGHT AND
THURSDAY. CHANCE OF RAIN WEDNESDAY NIGHT AND THURSDAY OVER
PARTS OF THE LOWER KOYUKUK AND MIDDLE YUKON VALLEYS. LOW
TEMPERATURES TONIGHT IN THE UPPER 20S TO MID 30S UNDER MOSTLY
CLEAR SKIES.

WEST COAST...
NO PRECIPITATION EXPECTED THROUGH THIS EVENING. RAIN DEVELOPING
IN THE YUKON DELTA WEDNESDAY MORNING OUT AHEAD OF A NORTHEASTWARD
MOVING SURFACE FRONT...SPREADING TO EASTERN NORTON SOUND AND THE
NULATO HILLS BY WEDNESDAY EVENING. RAIN LIKELY ON THE SOUTHERN
SEWARD PENINSULA COAST WEDNESDAY NIGHT AND THURSDAY.

ST LAWRENCE ISLAND...
RAIN  WEDNESDAY AND WEDNESDAY NIGHT AS THE SURFACE LOW AND FRONT
MOVE NORTHEAST. EAST WINDS 25-35 MPH OUT AHEAD OF THE FRONT
WEDNESDAY...BECOMING SOUTH AND DECREASING EARLY
WEDNESDAY EVENING AFTER THE FRONTAL PASSAGE.


COASTAL HAZARD POTENTIAL DAYS 3 AND 4...MODERATE TO HIGH SURF
POSSIBLE THURSDAY AND THURSDAY NIGHT ALONG THE CENTRAL/EASTERN
ARCTIC COAST WITH E WINDS AROUND 30 MPH.

&&

.FIRE WEATHER...
WARMER AND DRYER CONDITIONS EXPECTED THE NEXT FEW DAYS UNDER THE
RIDGE ALOFT.


&&

.HYDROLOGY...
RIVER LEVELS ON THE CHENA RIVER REMAIN ELEVATED BUT ARE GRADUALLY
FALLING. THE STAGE OF THE CHENA RIVER NEAR CHENA LAKES IS DOWN TO
23.3 FEET AND GRADUALLY FALLING AS WATER DRAINS FROM THE FLOOD
CONTROL PROJECT POOL. THE STAGE OF THE CHENA RIVER AT FAIRBANKS IS
CURRENTLY ABOUT 7.9 FEET AND FALLING SLOWLY. ELSEWHERE...NO
HYDROLOGIC ISSUES.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY FOR AKZ204.

SMALL CRAFT ADVISORY FOR PKZ210.

GALE WARNING FOR PKZ245.
&&

$$

RF SEP15



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