Alaska Extended Forecast Discussion
National Weather Service College Park MD
529 PM EDT Wed Jul 2 2025


Valid 12Z Sun 06 Jul 2025 - 12Z Thu 10 Jul 2025

...General Overview...
Warm core highs initially dominate portions of AK and eastern
Siberia. With time, shortwaves within the arctic beat down the
ridging across AK to various degrees, depending on the model,
dropping a front to at least the Brooks Range, if not a little
farther into the interior, particularly across eastern AK. To the
South, a couple different surface lows within a slow- moving 
upper level trough keep southern AK rainy and unsettled. 


...Guidance Evaluation/Preferences...
The guidance shows various solutions with both the frontal
progression into interior AK from the Brooks Range/North Slope and
cyclone progression into southeast AK/the AK Panhandle. For the
most part, the 12z ECMWF looks too emphatic in breaking down the
AK ridge and bringing colder air into the interior, while the 12z
Canadian is closest to the 12z NAEFS/00z ECMWF solutions in
cyclone progression across the northeast Pacific and portions of
the Gulf of AK.

For WPC's forecast blend, a near even blend of the deterministic
GFS/ECMWF/CMC/UKMET was used this weekend for pressures/ winds/ 
frontal placement/ QPF and subsequent PoPs adjustments, with an 
even blend of ensemble means from the 00z ECMWF/12z NAEFS used 
early to mid next week to account for the guidance uncertainty.
The remainder of the grids started with the 19z NBM before slight
nudges were made for the 12z ECMWF and its ensemble mean.  Due to
the model spread, confidence in this choice is no better than 
average.


...Weather/Hazards Highlights...
The influence of the strong upper ridge over portions of central
and northern AK early on will be felt as high temperatures rise
primarily into the 80s and 90s across the interior on July 5-6, 
with 70s and 80s on July 7, after which it drops into the 60s and 
70s -- the heat early on is the primary forecast hazard for 
central AK. The interior thermal trough appears to be driving
decent winds across portions of the northwest AK coast, though 
sub- gale, which then picks up behind a cold front as the warm
core high erodes. A dusting of snow appears possible across higher
elevations of the Brooks Range after the frontal passage. The 
guidance appears to use the incoming front, moisture moving in 
aloft from the Pacific, and shortwaves aloft to advertise heavy, 
possibly convective rainfall for the eastern interior on July 8-9 
as an additional hazard.

For southern portions of the state, lows tracking into the Gulf
and general upper level troughing will bring in Pacific moisture
from the south and southwest, resulting in unsettled weather with 
periods of heavy rainfall, particularly across the northern AK 
Peninsula, Kodiak Island, the AK Panhandle, and the Kenai 
Peninsula between July 5 and 8 which is the primary hazard for the
region. Some of the highest elevations of southeast AK could see
some accumulating snow. Gale-force winds are possible with these 
surface lows, particularly in places which normally experience gap
enhancement within east-southeast flow ahead of the cyclone, 
though probabilities for storm- force winds remain quite low due 
to both expected cyclone strength and the lack of a strong surface
high in the region. 

Roth




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