Alaska Extended Forecast Discussion
National Weather Service College Park MD
520 PM EDT Sun Jun 29 2025


Valid 12Z Thu 03 Jul 2025 - 12Z Mon 07 Jul 2025

...General Overview...

The upper pattern will be characterized by a mild/stable upper
level high over the North Slope/Brooks Range later this week and
into/through the weekend. Between 50-55N, a few systems will
traverse this latitude band which will keep the highest rain
chances across the Aleutians and into the Panhandle. This pattern
will be conducive to enhanced thunderstorms over the interior
which may spark some fire concerns.

...Guidance Evaluation/Preferences...

The 12Z model guidance suite was in relatively good agreement
overall with the handling of the main upper features, with
expected detail differences through the period. As with any blocky
pattern, the biggest question is when and how the block breaks
down. The dynamical models largely agree that the upper high will
weaken but mostly remain in place by next week (day 8/Mon) and
this was seconded by the ECMWF AI/ML guidance as well. To the
south, there was much more spread in the timing/location of the
upper low(s) out of the Bering and into the Gulf. By next Sun/Mon,
the spread was extended west-to-east across ~30deg longitude with
the placement of the lead and/or trailing upper low. The ECMWF
AIFS was notably much farther west into the Bering by next
Sun/Mon vs the most farthest east ECMWF control (ex-HRES), roughly
forming the west/east bounds. While a consensus blend worked well
to start (days 4-6), trended toward the ensemble means which were
in between the two and more like continuity.

...Weather/Hazards Highlights...

The upper high will promote mild/warm temperatures with isolated
showers/storms for the North Slope/Brooks Range and much of the
interior, with temperatures rising into the 80s in the warmest
spots. Over the Tanana Valley, thunderstorm chances may increase
by later in the week as anomalous easterly flow around the upper
high increase instability when combined with warm/very warm
surface temperatures. Thunderstorms without much rainfall could
lead to fires started by lightning.

Stratiform rain will be favored across the Aleutians and into the
Panhandle (as well as skirting coastal Southcentral) as the
Bering-Gulf systems move through from west to east. Rainfall
amounts will be light to modest and temperatures will be near to a
bit below normal due to the cloud cover.


Fracasso




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