904  
FXAK69 PAFG 252143 CCA  
AFDAFG  
 
NORTHERN ALASKA FORECAST DISCUSSION...CORRECTED  
NATIONAL WEATHER SERVICE FAIRBANKS AK  
143 PM AKDT WED APR 25 2018  
   
DISCUSSION
 
 
A ACTIVE PATTERN ACROSS THE STATE TODAY THAT WILL MOST LIKELY  
CONTINUE THROUGH THE WEEKEND. STRONG LOW PRESSURE IN THE BERING  
SEA CONTINUE TO PRODUCE GUSTY WINDS TO THE WEST AND IN THE ALASKA  
RANGE. IT IS ALSO PRODUCING A MIX OF RAIN AND SNOW SHOWERS FROM  
TANANA WEST, AND IT LOOKS LIKE THAT WILL CONTINUE THROUGH THE  
WEEKEND. THERE IS SOME CLEARING IN THE INTERIOR BUT EXPECT SOME  
SHOWERS TO POP UP AROUND THE AREA STARTING THURSDAY. SOME FOG  
POSSIBLE IN THE VALLEYS AS BREAKUP CONTINUES AND WARMER AIR  
PERSISTS OVER THE SNOW.  
 
MODELS...HAVE BEEN DOING A PRETTY GOOD JOB WITH THE SHORT TERM.  
INITIALIZED AGAINST THE SURFACE ANALYSIS ABOUT 3 MB HIGH, SO WINDS  
MAY BE A COUPLE KNOTS HIGHER THAT CURRENT SOLUTIONS SUGGEST. THEY  
CONTINUE THE TIMING STRUGGLE WITH THE SHORTWAVES THAT WILL BE  
MOVING THROUGH THE AREA WITH NO CONCENSUS. THERE IS BETTER  
AGREEMENT ON THE FRONT MOVING ACROSS THE STATE ON SATURDAY.  
 
ALOFT...AT 500 HPA...RIDGING REMAINS ALONG 77N THEN SOUTHEAST  
ACROSS THE BEAUFORT SEA, AND SOUTHEAST OVER CENTRAL YUKON  
TERRITORY. A BROAD AREA OF LOWER HEIGHTS AROUND A STACKED 509 DAM  
LOW OVER GAMBELL COVERS THE WESTERN 1/2 OF MAINLAND ALASKA, THE  
CHUKCHI SEA, THE BERING SEA, AND SOUTH OF THE ALEUTIANS OVER THE  
NORTH PACIFIC. SEVERAL SHORTWAVES WILL MOVE NORTH OVER THE WEST  
COAST THE NEXT 24 HOURS, WHILE A STRONGER SHORTWAVE WILL MOVE TO  
THE SOUTHWEST COAST AND BRISTOL BAY THURSDAY MORNING, AND WILL LIE  
FROM SHISHMAREF TO MCGRATH TO THE SOUTHERN TIP OF KODIAK ISLAND BY  
THURSDAY AFTERNOON, THEN SPITS WITH THE NORTHERN PORTION SWINGING  
NORTH TO THE ARCTIC COAST BY FRIDAY MORNING, AND THE SOUTHERN HALF  
MOVING SOUTH OF THE ALASKA RANGE. A 516 DAM LOW NORTH OF KAMCHATKA  
WILL SWING AROUND THE PRIMARY LOW TO ST MATTHEW ISLAND THURSDAY  
AFTERNOON, THEN OVER THE LOWER YUKON DELTA BY FRIDAY MORNING AT  
519 DAM. AS IT GETS CAUGHT UP IN THE FLOW AROUND THE PRIMARY LOW  
WHICH REMAINS QUASI STATIONARY IN THE WESTERN CHUKCHI SEA IT WILL  
MOVE INTO THE CENTRAL INTERIOR FRIDAY NIGHT AND TROUGHING WILL LIE  
FROM KIVALINA TO TANANA TO SKAGWAY. THE CLOSED LOW MERGE WITH THE  
PRIMARY LOW BY SATURDAY MORNING AND THE TROUGH MOVES TO LIE FROM  
POINT HOPE TO BETTLES TO EAGLE. ANOTHER WAVE WILL APPROACH THE  
WEST COAST FRIDAY NIGHT. AT 850 HPA...TEMPERATURES WILL REMAIN IN  
THE 0C TO -10C RANGE THROUGH SATURDAY. AT 925 HPA...STILL SEEING  
SOME 15 TO 25 KT WINDS SO GUSTS TO 40 MPH ARE STILL POSSIBLE OVER  
SOME OF THE INTERIOR SUMMITS INTO THURSDAY MORNING.  
 
SURFACE...A 976 MB LOW OVER GAMBELL WILL DRIFT NORTH TO THE  
WESTERN CHUKCHI SEA BY THURSDAY AFTERNOON, AND A 995 MB LOW WILL  
SPIN OUT OF SIBERIA TO BE OVER ST MATTHEW ISLAND. TROUGHING OVER  
THE ARCTIC COAST WILL PERSIST, BUT WEAKEN ON FRIDAY AS HIGH  
PRESSURE BUILD SOUTH OVER THE EASTERN ARCTIC COAST. A BUBBLE HIGH  
OVER THE INTERIOR WILL PERSIST AND MERGE WITH HIGH PRESSURE  
BUILDING IN FROM THE SOUTH THURSDAY NIGHT WITH A RIDGING EXTENDING  
FROM THE HIGH ARCTIC TO THE GULF OF ALASKA OVER THE ALCAN BORDER.  
THE LOWS IN THE CHUKCHI SEA AND AND EASTERN BERING SEA WILL MERGE  
FRIDAY AND A 982 MB LOW WILL MOVE TO THE CENTRAL BERING SEA AT  
984 MB, AND TO NUNIVAK ISLAND BY SATURDAY MORNING AT 990 MB. THE  
LOW THEN MOVES NORTH UP THE COAST TO THE SEWARD PENINSULA BY  
SATURDAY AFTERNOON. IN THE ARCTIC A 1020 MB HIGH WILL MOVE SOUTH  
OVER THE BEAUFORT SEA FRIDAY NIGHT AND SATURDAY. EXPECT THE  
PRESSURE GRADIENT TO TIGHTEN AND RELAX SEVERAL TIMES THROUGH  
SATURDAY WITH GUSTY WINDS DEVELOPING AS IT TIGHTENS.  
 
NORTH SLOPE AND BROOKS RANGE...FRONT IS WORKING ITS WAY OFFSHORE  
SO EXPECT CLEARING FROM WEST TO EAST THIS EVENING IF IT HAS NOT  
ALREADY. SOME PATCHY FOG DEVELOPING OVERNIGHT, MAINLY AROUND  
DEADHORSE WILL REDUCE VISIBILITY IN THE MORNING. WINDS SWINGING  
AROUND TO EAST AND SOUTHEAST AT 5 TO 15 MPH. WILL REMAIN NICE FOR  
THROUGH FRIDAY OVER MOST OF THE AREA, EVEN THE BROOKS RANGE WHICH  
MAY SEE SOME CLOUDS, AND SOME GUSTY WINDS AT TIMES.  
 
WEST COAST AND WESTERN INTERIOR...NOT MUCH CHANGE FROM YESTERDAY!  
EXPECT NOT QUITE AS WINDY, BUT IT WILL BE CLOUDY, RAINY, SNOWY,  
AND GENERALLY JUST KINDA YUCKY TO CONTINUE TO THE WEEKEND. THERE  
WILL BE SOME PERIODS OF CLEARING, BUT FOR THE MOST PART THEY WILL  
BE SHORT LIVED. EXPECT A MIX OF RAIN AND SNOW DEPENDING ON THE  
TIME OF DAY WITH MAINLY SNOW IN THE OVERNIGHT HOURS, EXCEPT SOUTH  
OR NORTON SOUND IT WILL BE MAINLY RAIN, WITH RAIN MIXING WITH SNOW  
OVERNIGHT. SNOWFALL AMOUNTS WILL VARY WIDELY, AND LOCALLY. THE  
HIGHER ELEVATIONS IN THE NULATO HILLS, BENDELEBEN MOUNTAINS, AND  
BAIRD MOUNTAINS WILL GET 2 TO 4 INCHES OF NEW SNOW, WITH LESSER  
AMOUNTS AT THE LOWER ELEVATIONS. TEMPERATURES WILL BE COOLING  
SLOWLY AS COLD AREA WRAPS AROUND THE LOW.  
 
EASTERN AND CENTRAL INTERIOR...MOSTLY SUNNY TO MOSTLY CLOUDY. SOME  
ISOLATED SHOWERS MAY POP UP DURING THE AFTERNOONS, MAINLY TO THE  
WEST OF FAIRBANKS. EXPECT SOME PATCHY FOG TO POP UP AS WATER  
STARTS TO SLOWLY OPEN UP IN THE INTERIOR. WINDS IN THE ALASKA  
RANGE CONTINUE TO BE GUSTY TO 45 MPH TODAY, AND WILL SETTLE DOWN A  
BIT TONIGHT, BUT EXPECT THEM TO BECOME GUSTY TO 45 MPH AGAIN  
TOMORROW AS THE PRESSURE GRADIENT ACROSS THE RANGE TIGHTENS UP  
AGAIN WITH LEESIDE TROUGHING REDEVELOPING. NO SIGNIFICANT  
PRECIPITATION IS EXPECTED THROUGH FRIDAY. AWAY FROM THE RANGE  
WINDS WILL BE VARIABLE TO 10 MPH IN MOST AREAS. TEMPERATURES WILL  
REMAIN SPRINGISH WITH HIGH AROUND FAIRBANKS IN THE LOWER 50S, AND  
LOWS AROUND 32 FOR MOST LOCATIONS.  
 

 
 
COASTAL HAZARD POTENTIAL DAYS 3 AND 4...POTENTIAL FOR SOME HIGH  
SURF AROUND SCAMMON BAY AND CAPE ROMANZOF FRIDAY AFTERNOON AND  
EVENING.  
 

 
   
FIRE WEATHER
 
NEAR RED FLAG CONDITIONS CONTINUE NEAR THE ALASKA  
RANGE. WINDS CONTINUE TO GUST TO AROUND 50 MPH THIS AFTERNOON.  
GUSTY WINDS WILL CONTINUE THROUGH THURSDAY WITH GUSTS TO 45 MPH  
NEAR THE ALASKA RANGE. WINDS WILL BE STRONG AND GUSTY AT TIMES  
THROUGH THE WEEKEND. RELATIVE HUMIDITY VALUES WILL FALL THROUGH  
FRIDAY INTO THE 20S, THEN REBOUND SOME ON THE WEEKEND INTO THE  
30S. HIGH TEMPERATURES IN THE 40S AND 50S THROUGH THE WEEKEND.  
OUTSIDE THE TANANA VALLEY MINIMUM RELATIVE HUMIDITY VALUES  
GENERALLY ABOVE 30 PERCENT AND WINDS IN THE VALLEYS 5 TO 15 MPH.  
THERE IS SLIGHT CHANCE OF THUNDERSTORM ACTIVITY MAINLY WEST OF  
FAIRBANKS THURSDAY AND FRIDAY.  
 

 
 
EXTENDED FORECAST FOR DAYS 4 TO 7...A LOW PRESSURE SYSTEM MOVING  
ACROSS THE BERING SEA WILL SPREAD A MIX OF SNOW AND RAIN TO THE  
WEST COAST FRIDAY NIGHT AS IT MOVES TO THE LOWER YUKON DELTA AT  
990 MB SATURDAY MORNING, AND THE SEWARD PENINSULA SATURDAY  
AFTERNOON. THIS WILL BRING SHOWERS TO INTERIOR LOCATIONS SATURDAY  
AFTERNOON THROUGH SUNDAY MORNING. ANOTHER FAIRLY STRONG CHINOOK  
WIND EVENT ACROSS THE ALASKA RANGE BRINGS SOUTH WINDS GUSTING 40  
TO 60 MPH TO THE NORTH SLOPES AND ADJACENT AREAS. EXPECT  
TEMPERATURES NEAR SEASONAL NORMALS ACROSS THE FORECAST AREA. IN  
THE CENTRAL INTERIOR HIGHS WILL BE IN THE UPPER 40S TO MID 50S,  
WITH OVERNIGHT LOWS AROUND 32.  
 

 
   
HYDROLOGY
 
SOME OF THE INTERIOR RIVER GAGES ARE COMING ONLINE,  
BUT MOST RIVERS REMAIN FROZEN. FOR THE GAGES AVAILABLE THEY SHOULD  
BE USED WITH CAUTION AS THEY MAY BE ICE AFFECTED.  
 

 
   
AFG WATCHES/WARNINGS/ADVISORIES
 
 
SMALL CRAFT ADVISORY FOR PKZ200-PKZ210.  
 
HEAVY FREEZING SPRAY WARNING FOR PKZ210.  
 
BRISK WIND ADVISORY FOR PKZ215-PKZ220.  
 

 
 

 
 
SDB APR 18  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab AK Page Main Text Page