990
FXAK69 PAFG 081055
AFDAFG
NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
255 AM AKDT MON SEP 8 2025
SYNOPSIS
SCATTERED SHOWERS CONTINUE OVER THE CENTRAL AND EASTERN PORTION
OF THE STATE AS A BROAD, DEEP TROUGH FORMS ALONG THE WEST COAST,
DOWN TO THE KODIAK ISLANDS. A DEFORMATION BAND IS EXPECTED TO FORM
OVER THE CENTRAL/EASTERN PORTION OF THE STATE, WHICH WILL
CONTINUE TO PROVIDE SHOWERS THROUGH THE END OF THE WEEK. COLDER
AIR WILL BE BROUGHT DOWN FROM THE NW, TRANSITIONING THE RAIN IN
THE DEFORMATION BAND INTO SNOW OVER THE CENTRAL NORTH SLOPE
BEGINNING LATE TUESDAY NIGHT THROUGH THURSDAY WITH A RAIN/SNOW MIX
LIKELY FARTHER EAST.
KEY WEATHER MESSAGES
CENTRAL AND EASTERN INTERIOR...
- SCATTERED SHOWERS CONTINUE ACROSS THE NORTHWEST INTERIOR NEAR
BETTLES WITH AROUND 0.25" TO 0.5" OF RAINFALL THROUGH TUESDAY.
- MORE ISOLATED RAIN SHOWERS ARE EXPECTED ACROSS THE EASTERN
INTERIOR TODAY WITH RAIN ACCUMULATIONS UP TO 0.1".
- STEADY RAIN CHANCES CONTINUE FOR THE NORTHERN INTERIOR
THROUGHOUT WEDNESDAY WITH ISOLATED TO SCATTERED RAIN SHOWERS
ACROSS THE REMAINDER OF THE INTERIOR THROUGH THE END OF THE
WEEK.
WEST COAST AND WESTERN INTERIOR...
- LIGHT RAIN DIMINISHES ALONG THE WEST COAST WITH LIGHT RAIN
CONTINUING ACROSS THE WESTERN INTERIOR BY THIS EVENING.
- COOLER AND DRIER FOR THE WEST COAST TODAY AND SPREADING INTO THE
WESTERN INTERIOR ON TUESDAY.
- NORTHERLY WINDS INCREASING ALONG THE WEST COAST BEGINNING
TUESDAY.
NORTH SLOPE AND BROOKS RANGE..
- LIGHT RAIN CONTINUES ACROSS ALL BUT THE FAR WESTERN NORTH SLOPE
WITH RAIN TOTALS BETWEEN 0.33" AND 0.66", GREATEST BETWEEN
DEADHORSE AND ANAKTUVUK PASS.
- HIGHER ELEVATIONS OF THE BROOKS RANGE WILL SEE UP TO 1.0" OF
ADDITIONAL PRECIPITATION THROUGH TUESDAY WITH LIGHT SNOW
ACCUMULATIONS POSSIBLE.
- ACCUMULATING WET SNOW COMBINED WITH BLUSTERY NORTHEAST WINDS ARE
INCREASINGLY LIKELY ACROSS MOST OF THE NORTH SLOPE WEDNESDAY
NIGHT INTO THURSDAY. SNOW CHANCES DIMINISH THURSDAY NIGHT INTO
FRIDAY.
FORECAST ANALYSIS AND DISCUSSION
THE WEEK STARTS OFF WITH THE FAMILIAR BROAD TROUGHING ACROSS THE
WEST COAST, RESULTING IN SOUTHWESTERLY FLOW, ALOFT, FOR THE
MAJORITY OF THE STATE. REMNANTS OF THE FRONT WILL PROGRESS NE
WITH THE WEAKENING TROUGH, WHICH WILL RESULT IN MORE SHOWERS FROM
THE WESTERN INTERIOR TO THE EASTERN BROOKS RANGE. BEHIND THE
TROUGH, AN OCCLUDED SYSTEM WILL BE PROGRESSING E/NE ALONG THE
ALEUTIANS, REACHING KODIAK ISLAND BY TUESDAY NIGHT AND BEGIN TO
SLOW ITS PROGRESSION. AT THE SAME TIME, ANOTHER SHORTWAVE WILL BE
MOVING DOWN FROM THE CHUKCHI OVER THE WESTERN BROOKS RANGE. THIS
WILL GET ENTANGLED WITH THE LOW MOVING ACROSS THE ALEUTIANS,
STRENGTHENING TO A CLOSED LOW BY WEDNESDAY NIGHT. THESE FEATURES
WILL CREATE A DEFORMATION BAND ACROSS THE CENTRAL PORTION OF THE
STATE AND MORE SCATTERED SHOWERS THROUGH THE END OF THE WEEK. COLD
AIR WILL BE BROUGHT DOWN OVER THE BROOKS RANGE AS THE DEFORMATION
BAND FORMS, RESULTING IN SNOW OVER THE CENTRAL NORTH SLOPE AND A
RAIN/SNOW MIX FARTHER EAST.
FIRE WEATHER...NO UPDATE
SEE PREVIOUS VERSION
CONDITIONS STAY GENERALLY STATUS QUO FOR THE UPPER TANANA VALLEY
WITH GENERALLY SOUTHERLY CHINOOK FLOW PREVAILING THOUGH INCREASING
CLOUDS AND RAIN CHANCES SHOULD ALLOW FOR A GRADUAL COOLING TREND
LATE THIS WEEK. SPOTTY RAIN SHOWERS RETURN TO THE EAST-CENTRAL
INTERIOR THIS EVENING THEN SPREAD ACROSS THE EASTERN INTERIOR ON
TODAY INTO TUESDAY. WETTING RAINS ARE NOT EXPECTED WITH THESE
SHOWERS. DELTA JUNCTION WILL SEE GUSTS TO AROUND 35 MPH THIS
AFTERNOON AND EVENING BEFORE WINDS WEAKEN AND BECOME MORE
LOCALIZED WITHIN THE PASSES. THUNDER CHANCES MAY RETURN TO THE
EASTERN INTERIOR NEAR THE CANADIAN BORDER THURSDAY AND FRIDAY
AFTERNOONS.
HYDROLOGY...NO UPDATE
SEE PREVIOUS VERSION
WET WEATHER CONTINUES SPREADING NORTHEAST ACROSS MOST OF
NORTHWESTERN ALASKA TODAY AND TONIGHT. ADDITIONAL ACCUMULATION OF
0.25 TO 0.75 INCHES ARE FORECAST WITH LOCALLY OVER 1" AT HIGHER
ELEVATIONS, PARTICULARLY ACROSS THE WEST-CENTRAL BROOKS RANGE.
WATER LEVELS IN MAINSTEM RIVERS REMAIN ELEVATED AFTER LAST WEEK'S
HIGH WATER EVENT, BUT FORECAST RAINFALL IS EXPECTED TO LIMIT HOW
QUICKLY WATER LEVELS DROP. A FLOOD WATCH REMAINS IN EFFECT FOR THE
KOBUK RIVER WITH A FLOOD ADVISORY REMAINING IN EFFECT FOR KOBUK.
FOR THE MOST UP TO DATE FORECASTS AND FLOOD PRODUCTS, VISIT:
WEATHER.GOV/AFG AND WEATHER.GOV/APRFC
EXTENDED FORECAST DAYS 4-7
AT THE UPPER LEVELS BROAD TROUGHING PERSISTS OVER THE WESTERN HALF
OF THE STATE. WEDNESDAY, A SHORTWAVE FEATURE ROTATING AROUND A
PERSISTENT LOW PRESSURE REGION NEAR THE NORTH POLE ROTATES INTO THE
CHUKCHI SEA AND RAPIDLY STRENGTHENS AS IT ALIGNS WITH THE AXIS OF
THE BROAD TROUGH. THIS FEATURE STRENGTHENS ENOUGH TO FORM A CLOSED
OFF LOW OVER THE CHUKCHI SEA COAST BY THURSDAY MORNING. THIS LOW
WILL BE COOL ENOUGH AND WET ENOUGH TO PRODUCE A BAND OF SNOW THAT
WILL MOVE FROM THE SOUTHEAST TO THE NORTHWEST ACROSS THE NORTH SLOPE
WEDNESDAY NIGHT THROUGH FRIDAY. THIS SAME FEATURE WILL ALLOW FOR A
PERIOD OF SHOWERY CONDITIONS ACROSS THE CENTRAL INTERIOR AS THE BAND
FORMS AND MOVES NORTH. THIS SNOW IS EXPECTED TO BE QUITE WET AND
HEAVY DUE TO WARMER INITIAL SURFACE CONDITIONS.
ENSEMBLE SPREAD IS QUITE HIGH HOWEVER WITH A 25TH PERCENTILE AROUND
2 INCHES AND A 75TH PERCENTILE AROUND 5 TO 6 INCHES ACROSS THE NORTH
SLOPE FOR THE MULTI-DAY EVENT. WHICH SIDE OF THIS SPREAD ENDS UP
VERIFYING WILL LARGELY BE DECIDED BY THE CHARACTER OF THE SNOW. WE
ARE FAVORING A MORE MODEST FORECAST OF 2 TO 4 INCHES OF WETTER,
HEAVIER SNOW DUE TO THE EXPECTED PRESENCE OF WARMER SURFACE
TEMPERATURES WITH HIGHS IN THE MID 30S, BUT SHOULD TEMPERATURES
COOL SUFFICIENTLY GREATER ACCUMULATIONS OF FLUFFIER SNOW ARE
POSSIBLE.
-STOKES
COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE
AFG WATCHES/WARNINGS/ADVISORIES
AK...FLOOD WATCH FOR AKZ813-819.
PK...NONE.
TWOMBLY
EXTENDED - STOKES
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