FXAK02 KWNH 172118

PMDAK



Alaska Extended Forecast Discussion

National Weather Service College Park MD

518 PM EDT Mon Aug 17 2026



Valid 12Z Fri 21 Aug 2026 - 12Z Tue 25 Aug 2026



...Windy Bering Sea Storm to bring Heavy Rain/Coastal Flooding

Threats to West/Southwest Alaska Friday into Saturday...





...Pattern Overview and Guidance Evaluation and Preferences... 



Guidance offers similar larger scale flow evolution and threat

signals, bolstering forecast confidence, albeit with less than

stellar system timing differences to navigate. Favor a composite

blend of best clustered guidance of the 12 UTC GFS and GEFS/ECMWF

ensemble means. This solution best supports consistent threat

messaging and product continuity.



...Weather/Hazards Highlights...



System timing remains good in guidance with passage of a 

leading and moderately deep/organized system across the northern 

Gulf of Alaska into Friday. Expect lingering terrain enhanced 

rainfall over SouthCentral Alaska, with lesser amounts into the 

Southeast as the system loses influence. 



Meanwhile upstream, guidance develops energetic flow out from 

northeast Asia through the Bering Sea this week. Important local

phasing/timing details remain uncertain, but ample energy seems 

likely to support genesis of a potent maritime storm to impact the

Mainland heading into the weekend. The WPC Hazards Outlook linked

below has accordingly introduced a local WFO collaborated threat 

for heavy rain and high winds/coastal flooding issues for 

Western/Southwest Alaska Friday into Saturday. Widespread but 

diminishing activity then spreads over much of an unsettled 

Interior over the weekend into early next week. Meanwhile, system 

energy breaking underneath across the Alaska Peninsula into the 

Gulf of Alaska should also spawn moderate system genesis to 

spread organized enhanced rains and winds inland across southern

then Southeast Alaska Sunday/Monday. Another upstream Bering Sea 

system may work over the Bering Sea toward western Alaska early 

next week to monitor given still energetic flow early next week.



Schichtel





Additional 3-7 Day Hazard Information can be found on the WPC 

medium range hazards outlook chart at:

https://www.wpc.ncep.noaa.gov/threats/threats.php



WPC medium range Alaskan products including 500mb, surface

fronts/pressures progs and sensible weather grids can also be

found at:



https://www.wpc.ncep.noaa.gov/alaska/ak_5dayfcst500_wbg.gif

https://www.wpc.ncep.noaa.gov/alaska/akmedr.shtml

https://www.wpc.ncep.noaa.gov/alaska/ak_5km_gridsbody.html