Alaska Extended Forecast Discussion
National Weather Service College Park MD
719 PM EST Sun Nov 2 2025

Valid 12Z Thu 06 Nov 2025 - 12Z Mon 10 Nov 2025

...Strong low pressure system could affect the Aleutians Friday
into next weekend...

...Overview...

A mean upper trough axis is forecast to be atop the western 
Mainland through much of the extended period, as an amplified 
ridge holds over northwestern Canada into the Arctic Ocean just to
the trough's east, blocking its movement. A couple of rounds of 
energy aloft on the southern side of the trough and surface low 
pressure systems will move through the northeastern Pacific and 
bring some light to moderate precipitation to Southcentral and 
Southeast Alaska, along with moderate gap winds on the backside. 
Upstream, the next upper/surface low looks to reach the Aleutians 
vicinity Friday and into next weekend, with typical model spread 
in its placement. The trough pattern should gradually cool 
temperatures across much of the Mainland and the Alaska Peninsula 
compared to the short range, with the most below normal anomalies 
across the Y-K Delta.


...Guidance Evaluation/Preferences...

Model guidance is reasonably agreeable regarding the synoptic 
scale pattern described above, with most of the differences in the
early part of the period in the details. However, details like 
placement of individual surface low(s) in the Gulf/northeast 
Pacific in particular could cause sensible weather concerns. Most 
model guidance has low pressure in the Gulf of Alaska leading to 
some northwesterly gap winds on both sides of Kodiak Island, but 
the 12Z ECMWF took a low farther north into Southcentral by early 
Friday. This is possible but did seem to be against consensus that
shows an offshore low. Overall, the early part of the forecast 
used a multi-model blend of the operational guidance, with the 
blend smoothing out some of the individual model differences.

Greater model differences arise upstream as vort maxes moving 
east across the northern Pacific and from Kamchatka initially both
carry surface lows. Most guidance shows one low becoming dominant
by Friday, reaching the 960s or 950s mb, but the 12Z GFS 
maintains both lows as strong into early Saturday. There is 
typical track uncertainty with the surface low as it could cross 
the Aleutians perhaps multiple times in the mean track eastward. 
The 12Z ECMWF is once again slow to bring the low east compared to
the other models that are faster. As the forecast period 
progressed, gradually used more ensemble means in the model blend 
to temper these individual model differences, with the blend 
composed of 60 percent ensemble means by Days 7-8.


...Weather/Hazards Highlights...

As multiple surface lows combine in the Gulf/northeast Pacific by
Thursday, moist inflow will maintain precipitation chances across
Southcentral and Southeast Alaska through much of the week into 
next weekend. Totals should stay pretty modest though. Farther 
inland, light snow showers are possible across the Mainland. On 
the backside of the northeast Pacific low pressure pattern, gap 
winds are possible and could focus west and east of Kodiak Island.
These should generally be in the 30-45kt range, and thus staying 
below thresholds for a High Winds hazard. Light precipitation is 
possible across the Aleutians to Alaska Peninsula around Thursday,
but the stronger low pressure system affecting the Aleutians 
should come in with relatively heavier precipitation around Friday
and reaching the Alaska Peninsula later Saturday, depending on 
the low track and timing. High winds are also possible, with 
southerly flow ahead of the low system Friday, and then the core 
of the low pressure system may track over the western Aleutians 
Friday night and east across the Aleutians on Saturday. This 
allows for a High Winds area for Friday-Saturday in the Day 3-7 
Hazards. The low generally looks to weaken as it moves east into 
early next wee



Model guidance is reasonably agreeable regarding the synoptic 
scale pattern described above, with most of the differences in the
early part of the period in the details. However, details like 
placement of individual surface lows in the Gulf/northeast Pacific
in particular as they interact and possibly merge could cause 
sensible weather concerns. Most model guidance has low pressure in
the Gulf of Alaska leading to some northwesterly gap winds on 
either side of Kodiak Island, while GFS runs kept most low 
pressure farther south, which limits winds. The newer 18Z GFS has 
hints of a surface low farther north now though. Overall, the 
early part of the forecast used a blend of the 12Z ECMWF, 12Z and 
06Z GFS, and 12Z CMC.

Greater model differences arise upstream as vort maxes moving 
east across the northern Pacific and from Kamchatka initially both
carry surface lows, with the southern one seemingly becoming 
dominant. The model consensus for the low appears to be near the 
Aleutians late week into next weekend, but if and when the low 
crosses the Aleutians is in question, given model and ensemble 
member spread. The 12Z GFS seemed to be a fast and south outlier 
by next Saturday (though does have support from the albeit older 
00Z GFS Graphcast), while the 06Z GFS was a bit slower and farther
north like the ECMWF/CMC. Then the 12Z ECMWF retrogrades the low 
by next Sunday though, which may be questionable but depends on 
upstream energy. The 12Z CMC may have been the best middle ground 
with a steady track east. As the forecast period progressed, 
gradually used more ensemble means in the model blend to temper 
these individual model differences, with the blend composed of 60 
percent ensemble means by the end of the period.k, but will continue to monitor potential sensible 
weather impacts as it tracks toward the Mainland.

Alaska will generally see a cooling trend during the medium range
period. By Thursday, the Alaska Peninsula and Y-K Delta will see 
below average temperatures for both highs and lows with the core 
of the trough aloft, which should last there and expand farther 
north and east into late week. The North Slope and some eastern 
lower elevation areas like the Yukon Flats may be the main places 
that stay above average by next weekend. Southeast Alaska could be
slightly above normal on average as well. 


Tate




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