Alaska Extended Forecast Discussion
National Weather Service College Park MD
636 PM EDT Mon Oct 20 2025

Valid 12Z Fri 24 Oct 2025 - 12Z Tue 28 Oct 2025


...Heavy rain and gusty winds likely for the Southeast this week...

...Overview...

An upper low will drift slowly south across the Bering while 
multiple waves rotate around it. The low is forecast to elongate 
early next week as it shifts from over the Bering to the Gulf of 
Alaska. Another upper low is expected to linger over the Gulf 
through the weekend. This upper level pattern will produce several
surface low pressure systems that will track across the Aleutians
and into the Gulf, resulting in generally unsettled weather for 
southern Alaska, especially the Aleutians and Southeast Alaska. 
Southeast Alaska may see heavy rain and gusty winds as a 
relatively stronger low pressure systems approaches mid-to-late 
this week. 


...Guidance Evaluation/Preferences...

Model guidance continues to show relatively good agreement on the
overall large scale pattern, with some expected uncertainty in 
the details. The highest uncertainty will surround the evolution 
of low pressure moving from the Bering to the Gulf early next 
week. Previous model runs were showing some interaction with an 
Arctic low, but the 12Z model suite has backed off from that idea,
resulting in a cleaner consolidation of low pressure in the 
Bering this weekend. As the low gradually shifts south towards the
Gulf early next week, the evolution becomes a bit messier with 
several shortwave interactions that are harder for models to 
resolve. For now, a blend of the best clustered deterministic 
models (12Z GFS and ECMWF) and ensemble means from the GEFS and 
ECENS produced a decent forecast that represents the pattern well.

WPC's forecast used a blend of the latest runs of the available 
deterministic models (GFS/ECMWF/CMC/UKMET) for Friday and 
Saturday, added ensemble means from the GEFS and ECENS (20% of 
blend) on Sunday, and used a mix of the deterministic GFS and 
ECMWF (60% of blend) and ensemble means from the GEFS and ECENS 
(40% of blend) for Monday and Tuesday. This maintained good 
consistency with yesterday's forecast and represents the pattern 
well, smoothing out model differences while maintaining some 
detail through the end of the period. 


...Weather/Hazards Highlights...

Another round of heavy precipitation (with mountain snow) is 
forecast for Southeast Alaska mid-to-late this week as a low 
pressure system approaches from the Gulf. This system should be 
pretty quick, producing a period of heavy precipitation Wednesday 
into Thursday, then moving swiftly into Canada. Strong, gusty 
winds will likely accompany this system on Thursday. The heaviest 
winds (and consequently waves) will be offshore though, but this 
will create a significant maritime threat. Some moderate gap winds
may be present in favorable locations on the backside of this low
as well.

Precipitation chances may linger over southern and Southeast 
Alaska through the weekend and into Monday as low pressure lingers
over the northern Gulf with troughing extending along the coast. 
Generally unsettled weather can be expected, but nothing 
particularly hazardous is forecast. Precipitation chances should 
decrease on Tuesday as high pressure nudges towards the region 
from the northwest, steering an approaching Pacific low to the 
south of the state.

Meanwhile, low pressure in the Bering is forecast to slowly move 
south late this week into the weekend. Winds and precipitation 
associated with this low should remain over the open waters of the
Bering, then move over the Aleutians late this weekend. Little to
no impacts are expected for western Alaska from this system. This
low will spawn several fronts that will pivot around it while it 
is over the Bering, then one dominant frontal system will emerge 
across the Aleutians into the Gulf early next week.

Quiet weather is expected for northern and interior Alaska with 
relatively higher pressure forecast to develop over these regions 
this weekend into early next week. High pressure combined with 
generally southerly flow will result in above normal temperatures 
through the period. 


Dolan




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