721
FXAK69 PAFG 181327
AFDAFG
NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
527 AM AKDT TUE AUG 18 2026
KEY MESSAGES
CENTRAL AND EASTERN INTERIOR...
-FIRE WEATHER CONCERNS REMAIN ELEVATED IN THE UPPER TANANA VALLEY
DUE TO LOW CHANCES OF WETTING RAINS, NEAR-CRITICAL TEMPERATURES/RHS,
AND A NON-ZERO CHANCE FOR AN ISOLATED THUNDERSTORM.
-RAIN SHOWERS CONTINUE TUESDAY (EXCEPT FOR IN THE UPPER TANANA),
WITH UP TO 0.5 INCHES POSSIBLE IN THE VALLEYS AND 0.5 TO 1.25 INCHES
OF PRECIPITATION POSSIBLE OVER TERRAIN, WITH THE HIGHEST AMOUNTS
WEST OF FAIRBANKS.
-TEMPERATURES WILL BE BELOW NORMAL TUESDAY, WITH HIGHS IN THE
LOW/MID 60S THROUGHOUT MOST OF THE REGION. TEMPERATURES BRIEFLY WARM
ON WEDNESDAY AS RIDGING BUILDS INTO THE CENTRAL AND EASTERN
INTERIOR. HIGH TEMPERATURES ARE EXPECTED TO BE IN THE MID/UPPER 60S.
WEST COAST AND WESTERN INTERIOR...
-A HYDROLOGIC OUTLOOK IS IN EFFECT UNTIL 4 PM TUESDAY FOR HEADWATER
STREAMS OF THE KOYUKUK AND MIDDLE YUKON RIVER BASINS AS 0.5-1.25
INCHES OF RAINFALL HAS FALLEN SO FAR, WITH ANOTHER 0.5-1.25 INCHES
POSSIBLE THROUGH TUESDAY, WHICH MAY CAUSE SIGNIFICANT RISES IN
SMALLER HEADWATER STREAMS. SHOWERY CONDITIONS CONTINUE THROUGH THE
WEEKEND, THOUGH PRECIPITATION TOTALS WILL BE LIGHTER (<0.5 INCHES A
DAY).
-NORTHERLY WINDS CONTINUE IN THE BERING STRAIT THROUGH WEDNESDAY
EVENING, WITH GUSTS UP TO 45 MPH EXPECTED.
-ANOTHER LOW IS SET TO ENTER THE BERING SEA ON FRIDAY. MODEL
GUIDANCE IS STILL NOT IN AGREEMENT ON LOCATION AND SPECIFIC
INTENSITY, THOUGH THERE IS AGREEMENT THAT IT WILL BE WEAK.
NORTH SLOPE AND BROOKS RANGE...
-A HYDROLOGIC OUTLOOK IS IN EFFECT UNTIL 4 PM TUESDAY FOR HEADWATER
STREAMS OF THE KOYUKUK HEADWATERS AS 1 INCH OF RAINFALL HAS FALLEN
SO FAR WITH ANOTHER 0.5-1.25 INCHES POSSIBLE THROUGH TUESDAY, WHICH
MAY CAUSE SIGNIFICANT RISES IN SMALLER HEADWATER STREAMS. RAIN
CONTINUES IN THE BROOKS RANGE AND ALONG THE NORTH SLOPE, WITH DAILY
TOTALS RANGING FROM 0-0.5 INCHES AND 0-0.25 INCHES RESPECTIVELY.
-TEMPERATURES COOL OFF ON THE NORTH SLOPE TUESDAY AND WEDNESDAY,
WITH HIGH TEMPERATURES IN THE MID/UPPER 50S FROM POINT LAY SOUTH AND
UPPER 30S/40S NORTH OF POINT LAY TUESDAY AND IN THE UPPER 30S/LOW 40S
EVERYWHERE EXCEPT FOR AROUND POINT LAY AND UMIAT (WHICH WILL BE IN
THE LOW 50S) ON WEDNESDAY. TEMPERATURES THEN WARM INTO THE MID
40S/MID 50S ON THE COAST AND INTO THE 60S INLAND TO FINISH OUT THE
WEEK.
SYNOPSIS
WEAK TROUGHING PERSISTS IN PORTIONS OF NORTHERN ALASKA BEFORE
ANOTHER SYSTEM MOVES INTO THE BERING ON FRIDAY. THE ONLY REGION OF
THE CWA EXPECTED TO AVOID WETTING RAIN IS THE UPPER TANANA VALLEY,
THOUGH CHANCES FOR AN ISOLATED THUNDERSTORM OR TWO ARE POSSIBLE
TUESDAY THROUGH THURSDAY. ON THE OTHER END OF THE SPECTRUM, THE
NORTHWEST INTERIOR/SOUTHWESTERN BROOKS RANGE WILL STAY CONSISTENTLY
SHOWERY. OTHER REGIONS IN NORTHERN ALASKA WILL BE SOMEWHERE IN
BETWEEN. TEMPERATURES SLIGHTLY WARM UP IN THE CENTRAL/EASTERN
INTERIOR ON WEDNESDAY AS HIGH PRESSURE BRIEFLY BUILDS. ANOTHER LOW
SYSTEM IS SET TO ARRIVE IN THE BERING AT THE END OF THE WEEK,
BRINGING THE POTENTIAL FOR WINDY CONDITIONS AND HEAVIER
PRECIPITATION ON THE WEST COAST. HOWEVER, THERE IS TOO MUCH MODEL
UNCERTAINTY TO SAY ANY SPECIFIC OTHER THAN THAT THE SYSTEM LOOKS TO
BE WEAK. TROUGHING IS EXPECTED TO CONTINUE THROUGH AT LEAST THE
WEEKEND.
.
SHORT TERM /THROUGH FRIDAY NIGHT/
THE UPPER LEVEL LOW THAT HAS BEEN MOVING ACROSS THE STATE OVER THE
LAST FEW DAYS HAS MOVED INTO CANADA, LEAVING WEAK TROUGHING FOR MOST
OF NORTHERN ALASKA IN ITS WAKE. POST-FRONTAL SHOWERS LINGER IN THE
CENTRAL AND NORTHERN INTERIOR ON TUESDAY, WITH CHANCES FOR A RUMBLE
OF THUNDER OR TWO IN THE WHITE MOUNTAINS/FORTYMILE COUNTRY WHERE
TEMPERATURES HAVE BEEN WARMER. MOST LOWLAND AREAS WILL SEE 0.5
INCHES OF RAIN OR LESS. BETWEEN 0.5 INCHES AND 1.25 INCHES COULD
FALL OVER HIGHER TERRAIN IN THE CENTRAL AND NORTHERN INTERIOR
TUESDAY, ESPECIALLY OVER SOUTHWEST ASPECTS. NORTHERLY WINDS INCREASE
IN THE BERING STRAIT WITH CONTINUED COLD AIR ADVECTION IN THE
REGION, WITH THE POTENTIAL FOR GUSTS UP TO 45 MPH.
ON WEDNESDAY, RIDGING BUILDS INTO THE CENTRAL AND EASTERN INTERIOR
FROM FAIRBANKS EAST, WHILE TWO WEAK LOWS ARRIVE ON THE WEST COAST-
ONE OVER THE BROOKS RANGE AND ONE OVER BRISTOL BAY. THE LOW OVER
BRISTOL BAY STAYS OUR OF OUR AOR FOR NOW, WHILE THE LOW OVER THE
BROOKS WILL BRING ANOTHER ROUND OF SHOWERS ALONG THE NORTH SLOPE AND
IN THE NORTHWEST INTERIOR. TOTALS WILL BE LIGHTER THAN EARLIER THIS
WEEK, WITH 24 HOUR TOTALS BETWEEN 0.05 AND 0.25 INCHES EXPECTED OVER
LOWER TERRAIN, WITH 0.25 TO 0.5 INCHES OVER HIGHER TERRAIN. RIDGING
IN THE CENTRAL/EASTERN INTERIOR WILL BRIEFLY WARM TEMPERATURES INTO
THE MID/UPPER 60S. IF SHORTWAVES BEING ADVECTED FROM THE LOW OVER
BRISTOL BAY ARRIVE IN THE UPPER TANANA VALLEY AND/OR FORTYMILE
COUNTRY AROUND/AFTER PEAK HEATING, ISOLATED THUNDERSTORMS COULD
DEVELOP.
ALL 3 FEATURES SHIFT EAST ON THURSDAY. ISOLATED RAIN SHOWERS REMAIN
PRIMARILY IN THE NORTHERN/WESTERN INTERIOR AND ON THE WEST COAST,
BUT FEW, IF ANY, WILL BE WETTING. ANOTHER ROUND OF ISOLATED
THUNDERSTORMS IS POSSIBLE IN THE UPPER TANANA/FORTYMILE COUNTRY ON
THURSDAY IF THE SAME CONDITIONS REQUIRED ON WEDNESDAY ARE MET.
ANOTHER TROUGH ASSOCIATED WITH A WEAK SURFACE LOW INTO THE BERING
MOVES OVER WESTERN ALASKA ON THURSDAY/FRIDAY. THERE IS DISAGREEMENT
BOTH AMONG ENSEMBLE MEMBERS AND BETWEEN ENSEMBLE MEANS IN INTENSITY
AND LOCATION, THOUGH THE MOST AGGRESSIVE MEMBERS HAVE THE LOW
BOTTOMING OUT AT ONLY 980 HPA. COASTAL FLOODING CONCERNS ARE MINIMAL
TO NONE AT THIS TIME, SINCE THE SYSTEM IS QUICK-MOVING AND WIND
GUSTS WILL BE RELATIVELY CALM (50+ MPH GUSTS DON'T SHOW UP IN THE
NBM UNTIL THE 90TH PERCENTILE). THIS LOW WILL ALSO BRING MORE
WIDESPREAD PRECIPITATION FOR THE WEST COAST AND WESTERN INTERIOR.
GIVEN THE UNCERTAINTY OF THE LOW PLACEMENT/STRENGTH THERE IS
CONSIDERABLE UNCERTAINTY IN PRECIPITATION TOTALS. THIS IS ESPECIALLY
TRUE FOR THE SOUTHERN SEWARD PENINSULA, BECAUSE IF FLOW IS MORE
SOUTHERLY, OROGRAPHIC LIFT OVER THE HIGHER TERRAIN IN THE MIDDLE OF
THE PENINSULA WILL BE MUCH MORE EFFECTIVE THAN IF FLOW IS
SOUTHWESTERLY/SOUTHEASTERLY. THERE IS OVER 1 INCH OF SPREAD BETWEEN
THE NBM 25TH AND 75TH PERCENTILES AROUND NOME FOR 24 HOUR PRECIP
TOTALS ON FRIDAY.
LONG TERM /SATURDAY THROUGH MONDAY/
AT THE START OF THE LONG TERM PERIOD THE LOW PRESSURE THAT WILL
BRING MODERATE TO HEAVY RAINFALL AND GUSTY WINDS TO PARTS OF THE
WEST COAST, WILL BE MOVING SOUTHEAST TOWARDS THE GULF OF ALASKA.
THIS LOW IS PAIRED WITH AN ARCTIC TROUGH STEMMING FROM AN AREA
OF LOW PRESSURE IN THE HIGH ARCTIC. AS THESE FEATURES MOVE
EASTWARD IT WILL BRING ISOLATED TO SCATTERED RAIN SHOWERS WITH
IT ACROSS THE EASTERN HALF OF NORTHERN ALASKA. BEHIND THIS
SYSTEM A RIDGE OF HIGH PRESSURE STEMMING FROM THE NORTH PACIFIC
RIDGE IS EXPECTED TO BUILD INTO THE BERING SEA. THIS RIDGE WILL
HELP TO INFLUENCE THE MOVEMENT OF LOWS IN THE NORTH PACIFIC AND
ARCTIC AS WE MOVE INTO EARLY NEXT WEEK.
MODEL ENSEMBLES ARE IN GOOD AGREEMENT ON THE RIDGE AXIS
DEVELOPING IN THE BERING SEA, AND A STRONG ARCTIC LOW MOVING
TOWARDS WRANGEL ISLAND IN THE CHUCKCHI SEA. WHERE MODELS BEGIN
TO DIVERGE IS HOW THE LOW INTERACTS WITH THE RIDGE AXIS. THIS
ARCTIC LOW COULD POTENTIALLY FLATTEN AND SHIFT THE RIDGE AXIS
EASTWARD. IF THIS OCCURS WE COULD SEE AN ATMOSPHERIC RIVER
DEVELOP AND MOVE ONTO THE WEST COAST. THE FLATTENED RIDGE WOULD
ALLOW FOR SOUTHWEST FLOW TO TAP INTO TROPICAL MOISTURE AND
ADVECTING IT ONTO THE WEST COAST. THE GFS ENSEMBLE IS MUCH MORE
AGGRESSIVE IN ADVECTING THIS TROPICAL MOISTURE, BUT THE ECMWF
ENSEMBLE STILL HAS THIS SOUTHWEST FLOW. REGARDLESS OF HOW STRONG
THE MOISTURE ADVECTION WILL BE, IT COULD BE A WET START FOR THE
WORK WEEK ACROSS THE WEST COAST AND WESTERN INTERIOR.
COASTAL HAZARD POTENTIAL...
NO COASTAL HAZARDS ARE EXPECTED IN THE FORECAST PERIOD.
FIRE WEATHER
FIRE WEATHER CONCERNS WILL BE QUICKLY DROPPING OVER THE NEXT
FEW DAYS ACROSS MUCH OF NORTHERN ALASKA. TEMPERATURES WILL BE
COOLING ACROSS THE INTERIOR AND ARCTIC PLAINS TO THE 50S/60S.
THESE COOLER TEMPERATURES WILL BE ACCOMPANIED WITH CLOUD COVER
AND ISOLATED TO SCATTERED RAIN SHOWERS. WE WILL CONTINUE TO SEE
MODERATE RAINFALL UP TO AN INCH ACROSS THE KOYUKUK VALLEY AND
CENTRAL BROOKS RANGE. ACROSS THE REST OF THE WESTERN/CENTRAL
INTERIOR WE CAN EXPECT 0.10" TO 0.40" OF RAINFALL. THIS RAINFALL
WILL STEADILY BECOME MORE ISOLATED AS WE MOVE INTO WEDNESDAY.
THERE IS A NON ZERO CHANCE THAT WE COULD SEE A THUNDERSTORM OR
TWO TUESDAY AFTERNOON ACROSS THE CENTRAL/EASTERN BROOKS RANGE
AND IN THE HIGHER TERRAIN FROM EAGLE SUMMIT TO EAGLE.
THE EXCEPTION TO FIRE WEATHER CONCERNS DROPPING WILL BE THE
UPPER TANANA VALLEY AS DOWNSLOPING WILL BE ABLE TO PERSIST
TUESDAY AND WEDNESDAY. CONDITIONS WILL NOT BE AT THE CRITICAL
THRESHOLD LIKE THEY WERE MONDAY AFTERNOON, BUT OVER THE NEXT FEW
DAYS THEY WILL BE NEAR CRITICAL. TEMPERATURES WILL SLIGHTLY
COOL TO AROUND 70, AND WITH DOWNSLOPING THE MINIMUM RHS WILL BE
IN THE UPPER 20S. WINDS IN THE VALLEYS WILL GENERALLY BE FROM
THE SOUTHWEST AND LIGHT, BUT DURING PEAK HEATING WE COULD SEE
SOME MIXING OCCURING ALLOWING FOR GUSTS OF 20 MPH TO MIX DOWN
INTO THE VALLEY. OVERNIGHT IF THE SOUTHWESTERLY WINDS PERSIST
SIMILAR TO TUESDAY MORNING THERE WILL NOT BE THAT MUCH RECOVERY.
AS OF NOW WE DONT EXPECT THESE SOUTHWESTERLY WINDS TO MIX DOWN
INTO THE VALLEY FOR THE NEXT COUPLE OF NIGHTS, SO THE OVERNIGHT
RH RECOVERY SHOULD BE IN THE 70S. RAIN CHANCES DON'T RETURN TO
THE REGION TILL AROUND THURSDAY AFTERNOON, BUT THEY WOULD COME
IN THE FORM OF THUNDERSTORMS IF THEY DO DEVELOP. THESE CHANCES
ARE GOING TO HEAVILY RELY ON A WAVE OF UPPER-LEVEL ENERGY AND IF
IT MOVES THROUGH THE REGION DURING THE DAYTIME. THERE IS NOT A
LOT OF MODEL AGREEMENT ON THE TIMING, AND WE ARE CONTINUING TO
MONITOR THE FEATURE.
HYDROLOGY
0.5 TO 1.25 INCHES OF RAINFALL HAS FALLEN ACROSS THE CENTRAL
INTERIOR AND BROOKS RANGE IN THE PAST 24 HOURS. A STALLED FRONT
WILL ALLOW FOR AN ADDITIONAL 0.5 TO 1.5 INCHES OF RAINFALL OVER
THE NEXT 24 HOURS ACROSS THE REGION. THIS COULD LEAD TO RIVER
RISES ACROSS THE KOYUKUK AND THE MIDDLE YUKON RIVERS HEADWATERS.
WHILE NO FLOODING IS ANTICIPATED, SOME SMALLER CREEKS AND
STREAMS COULD BECOME BANKFULL.
AFG WATCHES/WARNINGS/ADVISORIES
AK...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM AKDT THIS AFTERNOON FOR PKZ806-
807.
SMALL CRAFT ADVISORY UNTIL 1 PM AKDT THIS AFTERNOON FOR PKZ808-
855-856.
SMALL CRAFT ADVISORY UNTIL 10 AM AKDT THIS MORNING FOR PKZ809.
SMALL CRAFT ADVISORY UNTIL 10 AM AKDT THIS MORNING FOR PKZ854.
KEY MESSAGES...SCHLEZINGER
SYNOPSIS...SCHLEZINGER
SHORT TERM...SCHLEZINGER
LONG TERM...DENNIS
FIRE WEATHER...DENNIS
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