496  
FXAK69 PAFG 191559  
AFDAFG  
 
NORTHERN ALASKA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE FAIRBANKS AK  
659 AM AKST SUN NOV 19 2017  
 
FXAK69 PAFG 191559  
AFDAFG  
 
NORTHERN ALASKA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE FAIRBANKS AK  
659 AM AKST SUN NOV 19 2017  
   
SYNOPSIS
 
 
ALOFT...  
A LONG WAVE PATTERN CONSISTING OF A RIDGE OVER THE BERING SEA AND  
WEST COAST OF ALASKA WITH A TROUGH OVER NW CANADA AND EASTERN  
ALASKA WILL PERSIST THROUGH THE WEEK. A SERIES OF STRONG SHORT  
WAVE TROUGHS WILL MOVE THROUGH THE RIDGE AND INTO THE WEST COAST  
OF ALASKA EVERY 2 DAYS OR SO KEEPING THE VERY STORMY PATTERN  
THROUGH THE WEEK. THE WEST COAST AND WESTERN INTERIOR AND ARCTIC  
CAN EXPECT STRONG WINDS, HEAVY SNOW, POSSIBLE BLIZZARDS AND  
POSSIBLE COASTAL FLOODING WITH EACH OF THESE STORMS. THE EASTERN  
INTERIOR WILL REMAIN COLD THROUGH THE WEEK.  
 
A STRONG SHORT WAVE NOW OVER THE WEST COAST OF ALASKA WILL MOVE  
SOUTH OVER THE GULF OF ALASKA TONIGHT. THIS IS CAUSING HIGH WINDS  
AND SEVERE WINTER WEATHER AND HIGH SURF OVER WESTERN ALASKA THAT  
WILL MOVE SOUTH LATER TODAY.  
 
A SECOND STRONG SHORT WAVE NOW OVER THE SEA OF OKHOTSK WILL MOVE  
TO THE EASTERN BERING SEA MON PM, AND OVER THE WEST COAST OF  
ALASKA TUE AM, AND INTO THE WESTERN INTERIOR TUE. THIS WILL BRING  
ANOTHER ROUND OF HIGH WINDS AND WINTER WEATHER AND POSSIBLE  
COASTAL FLOODING OVER WESTERN ALASKA.  
 
A THIRD STRONG SHORT WAVE WILL MOVE EAST OVER THE BERING SEA WED.  
 
SURFACE... A LOW PRESSURE TROUGH FROM INUVIK TO WAINWRIGHT WILL  
MOVE JUST NORTH OF THE COAST TONIGHT. STRATUS, FLURRIES AND FOG  
WILL PERSIST ALONG THIS TROUGH.  
 
A 990 MB LOW OVER THE CHUKOTSK PENINSULA WILL MOVE TO NEAR MCGRATH  
AS A 990 MB LOW BY 3PM SUN THEN MOVE SOUTHEAST INTO THE GULF OF  
ALASKA SUN NIGHT. AN OCCLUDED FRONT STRETCHING FROM THIS LOW TO  
ANVIK TO KING SALMON WILL MOVE SOUTHEAST TODAY. AN EXTENSION OF  
THE OCCLUDED FRONT ALOFT STRETCHES NORTHWEST OF THE LOW AND WILL  
MOVE TO MCGRATH TO THE BERING STRAIT BY 3PM SUN, AND THEN MOVE  
SOUTHEAST OF THE FORECAST AREA TONIGHT. THERE WILL BE ANOTHER 2-4  
INCHES OF SNOW ALONG THE TRACK OF THE LOW AND OCCLUDED FRONT, WITH  
LIGHT SNOW LINGERING ALONG THE FRONT ALOFT. EAST WINDS 30G40 MPH  
ON THE EAST SIDE OF THE LOW AND FRONT AREA CAUSING BLOWING SNOW  
AND BLIZZARD CONDITIONS. WINDS TURN WEST 30-40 MPH WEST OF THE  
FRONT. IN THE SOUTHEAST QUADRANT OF THE LOW WEST WINDS ARE  
GUSTING AS HIGH AS 70 MPH OVER ZONES 213 AND 214 TODAY. WINDS  
WILL DECREASE THIS AFTER NOON AND EVENING.  
 
A STRONG LOW IN THE SEA OF OKHOTSK WILL MOVE TO JUST WEST OF  
ANADYR AS A 978 MB LOW BY 3PM MON, AND TO THE SOUTHERN CHUKSHI SEA  
AS A 975 MB LOW BY 3PM TUE. EXPECT ANOTHER ROUND OF RAIN, SNOW AND  
FREEZING RAIN WITH THIS OVER ZONES 213 AND 214 LAT MON AND  
POSSIBLE BLIZZARD OVER THE REMAINDER OF THE WEST COAST ALSO EXPECT  
SOUTH WINDS 40 KT AHEAD OF THE LOW TURNING WEST 40-50 KT SOUTHEAST  
OF THE LOW. WILL ISSUE MORE WWA FOR THIS MON AFTER THE CURRENT  
ROUND OF STORMS END.  
 

 
   
DISCUSSION
 
 
DETERMINISTIC MODELS HAVE SOME INITIALIZATION ISSUES. AT H500 IN  
THE RIDGE OVER THE WEST COAST OF ALASKA, ROABS AT KOTZEBUE, NOME,  
BETHEL AND ST PAUL ALL SHOW 20M HIGHER HEIGHTS THAN INDICATED BY  
ANY OF THE MODEL INITIALIZATIONS. THE IR SAT PIC COMBINE WITH THE  
SHEMYA RAOB SHOW THAT THE TROUGH WEST OF THE RIDGE SHOULD BE A BIT  
SHARPER AND DEEPER THAN MODELS INDICATE AS WELL. RESULT IS THAT  
THE SURFACE FEATURES MAY BE A BIT STRONGER THAN MODELS INDICATE.  
 
THE 06Z SURFACE ANALYSIS SHOWS THAT ALL MODELS AT ABOUT 5 MB TO  
WEEK ON THE DEPTH OF THE SURFACE LOW JUST NORTH OF PROVIDENIYA.  
THIS WILL RESULT IN THE SURFACE LOW REMAINING ABOUT 5 MB DEEPER  
THAN MODELS INDICATE THROUGH 3PM THIS AFTERNOON, SO WE WILL ADD 5  
KT TO WHAT MODEL WINDS WOULD INDICATE CLOSE TO THE LOW CENTER  
THROUGH THIS AFTERNOON. THIS BEARS OUT WITH THE 10Z ANADYR  
OBSERVATION SHOWING 50G70KT, AND QUICK SCAT WINDS OF 55KT. WILL  
HAVE STORM FORCE WINDS MARINE ZONE 210 AND PUBLIC ZONES 213 AND  
214 TODAY.  
 
THE GFS AND ECMF MOVE THE STRONG LOW FROM THE BERING STRAIT SOUTH  
MORE SLOWLY TODAY THEN THE NAM. SINCE THE LOW IS DEEPER THAN  
MODELS INDICATE AND WILL THUS LIKELY MOVE MORE SLOWLY THAN MODELS  
INDICATE, AND THUS PREFER LINGERING PRECIP AND WINDS LONGER TODAY  
OVER THE SOUTHERN INTERIOR THAN MODELS INDICATE. AFTER THAT MODEL  
MOVEMENTS ARE PRETTY SIMILAR THROUGH 3PM MON. AFTER THAT START TO  
SEE SIGNIFICANT DIFFERENCES IN SHORT WAVE AND ASSOCIATED SURFACE  
LOW STRENGTH AND LOCATION BETWEEN MODELS. THE NAM AND GFS ARE A  
BIT SLOWER AND MORE SOUTHERLY WITH TRACKING THE NEXT STRONG LOW AS  
IT MOVES OVER NE RUSSIA ON TUE THAN THE ECMF. AT THIS POINT  
PREFER THE SLOWER NAM/GFS ON TUE, BUT THERE IS MUCH UNCERTAINTY.  
THIS UNCERTAINTY HAS MUCH IMPORTANCE ON AFFECTING POTENTIAL FOR  
COASTAL FLOODING SO NEEDS TO BE WATCHED CLOSELY.  
 
COASTAL HAZARD POTENTIAL DAYS 3 AND 4...  
HIGH SURF ZONE 214 THROUGH MIDNIGHT TONIGHT.WEST WINDS GUSTING TO  
60 MPH TODAY WILL PRODUCE A 3 TO 4 FOOT RISE IN SEA LEVEL ALONG  
THE COAST FROM STEBBINS TO SCAMMON BAY AND CAUSE HIGH SURF THROUGH  
TONIGHT. THE SURGE WILL CAUSE A RISE ON THE YUKON RIVER IN THE  
YUKON DELTA.  
 
POTENTIAL FOR COASTAL FLOODING ALONG THE WEST COAST  
TUE INTO WED BUT STILL MUCH UNCERTAINTY AS TO OCCURRENCE AND  
LOCATIONS DUE TO MODEL DIFFERENCES AT THAT TIME RANGE. THIS WILL  
NEED TO BE WATCHED CLOSELY AS COULD BE A SIGNIFICANT STORM.  
 

 
   
AFG WATCHES/WARNINGS/ADVISORIES
 
 
HIGH SURF ADVISORY FOR AKZ212-AKZ214.  
 
WINTER STORM WARNING FOR AKZ214-AKZ215-AKZ216.  
 
BLIZZARD WARNING FOR AKZ207-AKZ209-AKZ210-AKZ211-AKZ212-AKZ213.  
 
WINTER WEATHER ADVISORY FOR AKZ208-AKZ223-AKZ225-AKZ227.  
 
HEAVY FREEZING SPRAY WARNING FOR PKZ200-PKZ210-PKZ215-PKZ220-  
PKZ225-PKZ230-PKZ235.  
 
GALE WARNING FOR PKZ200-PKZ215-PKZ220-PKZ225-PKZ230.  
 
STORM WARNING FOR PKZ210.  
 
SMALL CRAFT ADVISORY FOR PKZ235.  

 
 

 
 
JB NOV 17  
 
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