Alaska Extended Forecast Discussion
National Weather Service College Park MD
743 PM EDT Tue May 27 2025
Valid 12Z Sat 31 May 2025 - 12Z Wed 04 Jun 2025
...Synoptic Overview...
A large upper level low will be parked across the Bering
throughout the long range period. This low will help direct
various impulses of energy, mostly from the North Pacific, and
circulate them around itself, eventually absorbing each low. As
any North Pacific impulses round the southeastern side of the
upper low, the surface fronts will move into Southcentral, and
quickly dissipate as the fronts orthogonally cross the mountains.
High pressure and upper ridging look to become established across
the eastern Gulf and eastern Alaska, resulting in a prolonged
period of tranquil weather, assuming this pattern remains in
place into the middle of the upcoming workweek.
Across Northern Alaska, there may be small upper lows that remain
part of the broader trough, which could provide for windier and
unsettled conditions along the Bering Strait coast, but otherwise
a general cutting off of the energy coming from shortwave
impulses from the Pacific should keep most areas quiet weather-
wise.
...Guidance Evaluation and Preferences...
The EC was largely removed from the forecast for being the outlier
regarding the strength and track of the surface low over the
southern Bering/eastern Aleutians/Alaska Peninsula. The EC phases
the energy far more than the other guidance, resulting in a much
stronger low (977 in the EC at 12Z Sun vs. 990 on average in the
other guidances a bit later). Since the other guidance were
functionally the same (multiple weaker lows taking longer to merge
into a weaker single low), they were blended together for the Days
4-6/Sat through Mon period. By Day 7 and beyond, the details
become so unclear that a predominant ensemble blend was used,
which blended out many of the forecast details by that time frame.
Presumably the pattern will remain similar on Day 8 as it was on
Day 4 with a low over the Bering and ridging over the eastern Gulf
and Mainland, so it's likely those details will resolve in the
coming days. Regardless, as is typical of late Spring/early
Summer, there are no big storms in any larger percentage of the
guidance.
...Weather/Hazards Highlights...
...Heavy rain will impact portions of the Panhandle Friday as well
as portions of Southcentral and Southwest Alaska through the
weekend...
&&
Wegman
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