Alaska Extended Forecast Discussion
National Weather Service College Park MD
727 PM EDT Wed Oct 1 2025

Valid 12Z Sun 05 Oct 2025 - 12Z Thu 09 Oct 2025

...Synoptic Overview...

The upper level pattern over Alaska will remain amplified through
the period (Sunday-Thursday) featuring a series of strong surface
lows and heavy precipitation potential. This weekend, deep 
troughing, anchored by an upper low over eastern Russia, will 
advance eastward through Alaska supporting a period of heavy 
rainfall this weekend into early next week. Behind this, amplified
ridging will briefly build over the Mainland by next Wednesday as
a deepening low pressure system crosses the Western Aleutians 
into the Bering Sea. The associated surface low will lift 
northeastward through the Bering sending a cold front into western
Alaska Wednesday or Thursday. Very gusty winds and moderate to 
heavy precipitation may accompany this system. 


...Guidance Evaluation and Preferences...

Models and ensembles remain in generally good agreement with the 
initial deep troughing shifting through Alaska this weekend. There
are some differences in the exact location of the surface low 
crossing from the Bering Sea into the Chukchi Sea, but a general 
compromise of the guidance resulted in a good starting point. The 
latest ECMWF came in slightly faster than its prior 00z run and 
the GFS is notably slower than the consensus with the cold front 
through the Gulf. After this system, the next system will move 
across the western Aleutians into the Bering Sea early next week. 
There is still a fair bit of spread on how deep the low actually 
gets, but deterministic guidance shows a low into the 960s mb 
while some ensemble members are even lower. The GFS is a bit on 
the east side of the forecast track while the ECMWF is in the 
middle and serves as a good basis for the late period forecast. 
This low should track northward through the Bering Sea, on a 
similar track to the initial weekend low. At least right now, much
of the guidance keeps the actual low track west of the West 
Coast, but associated hazards will extend inland. 

The WPC forecast for tonight was based on the ECMWF with the CMC 
and UKMET the first half of the period. By days 5-7, used 
increasing weighting of the ensemble means which helped smooth out
some of the smaller scale differences. 


...Weather/Hazards Highlights...

The first Bering Sea low in the northern Bering will continue to 
bring some gusty wind and coastal flooding threat across parts of 
the western mainland with with moderate precipitation that may 
reach inland areas of the western and central Interior north to 
the Brooks Range as well. As the upper- wave/surface frontal 
system progress eastward over the Gulf later this weekend and into
early next week, heavy rain will be possible at the lower 
elevations at times with upslope flow into the coastal ranges. 
This will especially be the case around Prince William Sound and 
east to Yakutat where several inches of rainfall can be expected. 
Higher elevation snow will also impact the mountains but freezing 
levels will remain high enough that the passes will not be 
affected. A heavy rain hazard remains for Sunday-Monday on the WPC
Hazards chart. The next system crossing the far western Aleutians
will bring increasing precipitation by next week for parts of the
Aleutians and gusty winds. Expect strong to Gale force winds over
the Bering Sea, with some concern particularly for St. Lawrence 
Island. Gusty winds and coastal flooding concerns will need to be 
monitored for parts of the Western coast with too much uncertainty
on the exact placement of the low for any highlighted hazard 
areas. 

Temperatures looks to remain near to above normal through the 
period for nearly all of the state. Daytime highs could be 10 to 
20 degrees above normal in some spots, especially earlier in the 
period. This equates to 30s for the North Slope and 50s and 60s 
farther south near the Southern Coast. Temperatures should trend 
cooler through much of the period but still above average for this
time of the year. 


Santorelli



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