Alaska Extended Forecast Discussion
National Weather Service College Park MD
703 PM EDT Thu Jun 26 2025


Valid 12Z Mon 30 Jun 2025 - 12Z Fri 4 Jul 2025

...General Overview...

The main theme of the overall weather pattern expected next week
will be a broad upper low/trough that will be situated over the
northern Gulf, and an upper ridge axis that evolves into a closed
upper high over the western mainland towards the end of the week.
With an incoming upper low from the western Bering, this will tend
to form an omega block pattern that will likely have some staying
power from the middle of the week and beyond. Warm conditions
continue across the mainland with scattered to numerous showers 
and storms for the eastern Interior, and periods of light rain for
the southern coastal areas.

...Guidance Evaluation/Preferences...

The 12Z model guidance suite is in reasonably good agreement for
the start of the period Monday, and there has been a stronger
trend in the guidance for the shortwave trough dropping southeast
from the Bering to the western Gulf for early in the week. This
will tend to reinforce the upper low that will already be in place
across the northern Gulf. Looking ahead to Thursday, the CMC
becomes farther west than the model consensus/AIFS guidance with 
the upper low south of the Alaska Peninsula, and also with the low
approaching from eastern Siberia, so its contribution in the
preferred model blend is reduced for the end of the week. The
ensemble means were gradually increased to about half by next
Friday.

...Weather/Hazards Highlights...

A broad upper level low with reinforcing surface lows will be
present across the northern Gulf through most of the forecast
period. The upper ridge axis appears likely to build back in to
the north across the central and northern mainland going into the
middle of next week and potentially forming an omega block type 
pattern as a closed upper high likely develops. Meanwhile, a 
trough approaches from eastern Siberia for the middle to end of
the week, but does not appear to be all that impactful for now.

There will likely be an increase in shower and thunderstorm 
coverage going into Sunday and early next week across eastern 
portions of the Interior. Relatively moist northeasterly flow 
approaching the central and eastern portions of the Alaska Range 
will increase the potential for heavier rainfall, with the highest
totals where there is an upslope flow component where 1 to locally 2
inches will be possible. A heavy rainfall area remains on the WPC
hazards chart for the 29th and 30th for east-central portions of 
the Interior, although there has been a slight downward trend in
QPF with the 12Z guidance compared to yesterday. This rainfall 
would help to mitigate any ongoing fire weather concerns. Showers
are also expected for southeast Alaska as moist onshore flow 
continues courtesy of the loitering low over the northern Gulf.

Hamrick




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