Alaska Extended Forecast Discussion...UPDATED
National Weather Service College Park MD
612 PM EDT Thu Jul 10 2025

Valid 12Z Mon 14 Jul 2025 - 12Z Fri 18 Jul 2025


...Guidance Evaluation and Preferences...

Prefer a composite blend of reasonably well clustered guidance 
from the 12 UTC GFS/ECMWF/Canadian/UKMET models valid for 
Monday and Tuesday in a transitional pattern with near average
predictability and WPC product continuity. Opted to pivot to 
better clustered guidance from GEFS/ECMWF/Canadian ensemble means 
for next mid-later week amid growing forecast spread and 
uncertainty. Applied manual adjustments to this blend to develop a
deeper maritime surface low to the southeast of the eastern 
Aleutians into early next week and then especially for a mid-
later next week emerging Bering Sea storm considering favorable 
closed low upper support in guidance in both cases. 

...Pattern Overview and Weather/Hazards Highlights...

An initially blocky upper flow pattern lingering into early next 
week will be highlighted by closed upper lows/troughs both over 
the Bering Strait and also to the southeast of the eastern 
Aleutians, with progression to this point slowed with development
of an upper ridge up through the mainland. This ridge will 
support a period with very warm temps up through the 70s and for 
some spots 80F up through the Interior and into the North Slope, 
but a slow but steady transition next week toward flow progression
with an uncertain series of systems will act to moderate upper 
ridging and warmth.

Meanwhile to the south, an likewise uncertain series of impulses 
and surface lows moving over the Gulf of Alaska will bring some 
moderate rain chances into southern and southeast Alaska, and 
possibly more widespread activity with time next week for the 
Alaska Range and over the Mainland with upper ridge erosion.

Upstream, the guidance signal is growing to develop a Bering Sea
storm system mid-later next week. In this scenario, well 
organized enhanced rain and winds/waves would slowly and 
steadiliy work across the Bering Sea and Aleutians and then become
more directed into the western and Southwest mainland, possibly 
leading into eventual triple-point development to affect the 
AKpen and vicinity late period.

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