225  
FXAK69 PAFG 222118  
AFDAFG  
 
NORTHERN ALASKA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE FAIRBANKS AK  
118 PM AKDT MON OCT 22 2018  
   
DISCUSSION
 
 
THE NEXT ROUND OF WINTER WEATHER OVER INTERIOR ALASKA AND NORTH  
SLOPE WILL BE THE MAIN FORECAST CONCERN FOR THE NEXT COUPLE OF  
DAYS. A FAIRLY ACTIVE PATTERN WILL CONTINUE ACROSS NORTHERN ALASKA  
THIS WEEK INTO THE WEEKEND AS MULTIPLE LOWS MOVE INTO THE GULF OF  
ALASKA AND THEN INTO INTERIOR ALASKA. LATEST MODEL SOLUTIONS ARE  
IN FAIR AGREEMENT THROUGH THE FORECAST PERIOD REGARDING THE  
OVERALL SYNOPTIC PATTERN; HOWEVER THERE ARE SOME DISCREPANCIES  
WITH THE STRENGTH OF INDIVIDUAL LOWS OVER THE GULF OF ALASKA.  
 
ALOFT, AT 500 MB, A LONGWAVE TROUGH CURRENTLY OVER THE BERING SEA  
AND MAINLAND ALASKA WILL GENERALLY REMAIN IN PLACE THIS WEEK AS  
SEVERAL FEATURE MOVE WITHIN THE TROUGH. A STRONG SHORTWAVE  
CURRENTLY IN THE WESTERN GULF OF ALASKA WILL RAPIDLY DEEPEN THIS  
EVENING AND TONIGHT INTO A 523 DAM LOW OVER PRINCE WILLIAM SOUND  
BY TOMORROW MORNING. THIS LOW WILL MOVE NORTH INTO THE  
SOUTHWESTERN INTERIOR BY TUESDAY EVENING. A 525 DAM LOW CURRENTLY  
OVER THE PRIBILOFS WILL DEEPEN TO A 519 DAM LOW OVER SAND POINT BY  
TUESDAY AFTERNOON WITH ANOTHER 520 DAM LOW OVER UNALASKA. THESE  
TWO WILL MERGE TOGETHER TUESDAY EVENING AND MOVE INTO THE WESTERN  
GULF OF ALASKA BY WEDNESDAY EVENING. A 525 DAM LOW WILL EMERGE  
FROM THE NORTHERN PACIFIC OCEAN WEDNESDAY MORNING AND THEN MOVE  
NORTH INTO THE GULF OF ALASKA TO BE 200 MILES SOUTH OF PRINCE  
WILLIAM SOUND THURSDAY AFTERNOON.  
 
AT THE SURFACE, A CONGLOMERATION OF MULTIPLE LOW CENTERS  
CURRENTLY OVER THE GULF OF ALASKA WILL MERGE WITH A 985 MB LOW  
THAT WILL EMERGE FROM THE NORTHEAST PACIFIC THIS EVENING. THIS 985  
MB LOW WILL RAPIDLY DEEPEN AS IT TRAVELS NORTH INTO THE GULF OF  
ALASKA TONIGHT AND WILL BECOME A 969 MB LOW 100 TO 150 MILES SOUTH  
OF PRINCE WILLIAM SOUND BY TOMORROW MORNING. MODEL DISAGREEMENT  
REGARDING THIS LOW REMAIN, ESPECIALLY WITH THE STRENGTH OF THE  
LOW. THE ECMWF IS ABOUT 10 MB STRONGER THAN BOTH THE NAM AND GFS  
TOMORROW MORNING BEFORE THE LOW MOVES INLAND OVER SOUTHCENTRAL  
ALASKA. ITS ATTENDANT FRONT WILL MOVE NORTH OVER THE EASTERN  
ALASKA RANGE TOMORROW MORNING, THEN OVER THE EASTERN INTERIOR  
TOMORROW REACHING THE BROOKS RANGE BY LATE TUESDAY NIGHT. A 990 MB  
LOW CENTERED SOUTH OF NUNIVAK ISLAND WILL MOVE SOUTH OVER THE  
CENTRAL ALEUTIANS AND WEAKEN THROUGH WEDNESDAY. BY TOMORROW  
EVENING, ANOTHER STRONG LOW WILL MOVE NORTH INTO THE SOUTHERN GULF  
OF ALASKA BY THURSDAY MORNING AND THEN CONTINUE NORTH TO BE 150  
MILES SOUTH OF PRINCE WILLIAM SOUND FRIDAY MORNING.  
 
EASTERN AND CENTRAL INTERIOR...THE NEXT ROUND OF MESSY WINTER WEATHER  
WILL BE THE MAIN FOCUS OVER THE NEXT COUPLE OF DAYS, ESPECIALLY  
WITH TIMING AND PRECIPITATION TYPE. WITH THE LATEST ROUND OF  
GUIDANCE, IT LOOKS LIKE SNOW WILL DEVELOP OVER THE UPPER TANANA  
VALLEY EARLY TOMORROW MORNING AND SHIFT NORTH TO BE OVER FAIRBANKS  
TO CENTRAL AROUND NOON, THEN CONTINUE NORTH REACHING THE  
SOUTHEASTERN BROOKS RANGE BY MIDNIGHT TUESDAY. OVER THE SOUTHERN  
INTERIOR, PRECIPITATION WILL BE SHORT LIVED AND WILL BE INITIALLY  
SNOW AND WILL CHANGE OVER THE A RAIN/SNOW (POSSIBLY FREEZING  
RAIN) MIX LATE IN THE AFTERNOON BEFORE TAPERING OFF DURING THE  
EVENING. OVER THE NORTHERN INTERIOR, SNOW WILL PILE UP AGAINST THE  
SOUTHERN SLOPES AND FOOTHILLS OF THE BROOKS RANGE TUESDAY NIGHT  
INTO WEDNESDAY MORNING BEFORE TAPERING OFF TO SHOWERS LATER  
WEDNESDAY. THE HIGHEST SNOWFALL AMOUNTS ARE EXPECTED FROM  
LIVENGOOD TO CENTRAL NORTH, WHERE 2 TO 4 INCHES ARE EXPECTED AND  
TO THE SOUTH UP TO 2 INCHES ARE EXPECTED THROUGH WEDNESDAY  
AFTERNOON. IN VALLEY LOCATIONS SUCH AS FAIRBANKS AND NORTH POLE,  
SNOW AMOUNTS WILL BE NEGLIGIBLE DUE TO RAIN MIXING IN WITH SNOW.  
SOUTHERLY FLOW OVER THE EASTERN ALASKA RANGE WILL DEVELOP TUESDAY  
NIGHT AND CONTINUE INTO WEDNESDAY WHERE SOUTH GAP WINDS MAY FLIRT  
WITH ADVISORY CRITERIA. MAY ALSO SEE GUSTY EAST TO NORTHEAST WINDS  
OVER HILLS AND HIGHWAY SUMMITS TUESDAY AND TUESDAY NIGHT WITH  
SUSTAINED VALUES AROUND 15 TO 25 MPH WITH GUSTS TO AROUND 35 MPH  
POSSIBLE. NEXT ROUND OF PRECIPITATION WILL COME FRIDAY WHEN  
ANOTHER FRONT MOVES NORTH FROM THE GULF OF ALASKA.  
 
WEST COAST AND WESTERN INTERIOR...ISOLATED TO SCATTERED SHOWERS  
OVER NORTON SOUND AND YUKON DELTA WILL TAPER OFF THIS EVENING.  
NORTHEAST WINDS OVER THE BERING SEA, BERING STRAIT, AND CHUKCHI  
SEA WILL CONTINUE THROUGH LATE TOMORROW AND THEN INCREASE TUESDAY  
NIGHT TO GALE FORCE SUSTAINED WINDS WHICH WILL CONTINUE INTO  
WEDNESDAY AND THURSDAY. SNOW WILL DEVELOP OVER THE WESTERN  
INTERIOR TOMORROW AFTERNOON AND WILL CONTINUE INTO LATE WEDNESDAY  
AS SHOWERS WITH 1 TO 2 INCHES OF SNOW ACCUMULATION EXPECTED. THERE  
IS THE POTENTIAL TO SEE FREEZING RAIN OR RAIN MIX IN OVER VALLEY  
LOCATIONS INITIALLY AS THE PRECIP DEVELOPS AND AGAIN LATE  
MORNING/EARLY AFTERNOON WEDNESDAY. ELSEWHERE, SNOW SHOWERS ARE  
EXPECTED OVER THE NORTHWEST AND CHUKCHI SEA COASTAL LOCATIONS WITH  
NEGLIGIBLE SNOW ACCUMULATIONS EXPECTED AND RAIN SHOWERS OVER THE  
BERING SEA AND NORTON SOUND.  
 
NORTH SLOPE AND BROOKS RANGE...SNOW ASSOCIATED WITH A NORTHWARD  
MOVING FRONT WILL DEVELOP OVER THE SOUTHEASTERN BROOKS RANGE  
TOMORROW AFTERNOON AND THEN SPREAD NORTH OVER THE NORTH SLOPE  
TOMORROW NIGHT. COINCIDENT WITH THE DEVELOPING SNOW, EAST TO  
NORTHEAST WINDS WILL RAMP UP ALONG THE COAST WITH BLOWING SNOW  
BEING A POSSIBILITY ESPECIALLY OVER THE BEAUFORT SEA COAST AFTER  
MIDNIGHT TUESDAY, BUT NOT EXPECTING ANY SIGNIFICANT REDUCTION IN  
VISIBILITY. LATEST FORECAST SNOWFALL AMOUNTS OVER THE EASTERN  
BROOKS RANGE WILL BE 2 TO 4 INCHES, THE HEAVIEST BEING OVER THE  
SOUTH FACING SLOPES IN THE UPSLOPE FLOW. EAST OF UTQIAGVIK OVER  
THE NORTH SLOPE WILL SEE UP TO 2 INCHES, POSSIBLE MORE NEAR BARTER  
ISLAND. LESSER AMOUNTS AROUND AN INCH ARE EXPECTED FROM UTQIAGVIK  
WEST THROUGH WEDNESDAY AFTERNOON.  
 
COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE.  
 

 
   
AFG WATCHES/WARNINGS/ADVISORIES
 
 
SMALL CRAFT ADVISORY FOR PKZ210-PKZ220-PKZ225.  

 
 

 
 
LTH OCT 18  
 
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