Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
650 PM EDT Wed Apr 30 2025

Valid 12Z Sun 04 May 2025 - 12Z Thu 08 May 2025

...General Overview...

Much of the southern coast and parts of the Southeast will remain
in a wet pattern with the mean trough over the Gulf of Alaska.
Onshore shore flow will promote multiple round of moderate rain
and some snow further inland. Further west, a broad upper low is
expected to cross the Bering by early next week. Meanwhile, the
Arctic surface high will continue to be in place north of the
state resulting in sustained polar easterlies north of the Brooks
Range, and below average temperatures in many cases.


...Guidance/Predictability Assessment...

During the extended period there will be a mean trough over the
Gulf of Alaska, an Arctic high north of the state and a trough/low
traversing the Bering Sea toward the Gulf. In general, the
deterministic and ensemble guidance has a decent handle on the
overall evolution of each feature. It was noted that the latest
runs had an increase in initial clustering spread with the Gulf
system but returned to average spread by Day 5. On the contrary,
the Bering feature had a slight increase in initial clustering,
but then quickly returned to a wide spread in solutions.

WPC utilized a multi-model approach for the forecast, beginning
with the 12Z CMC/GFS/ECMWF/UKMET. The UKMET was dropped after Day
4 and replaced with ECMWF ensemble and GEFS means to help mute the
noise within the guidance for the Gulf of Alaska and the Bering
Sea lows.

...Weather/Hazards Highlights...

Wet and unsettled conditions will persist for the southern coast
and the Panhandle. Periods of rain and mountain snow are expected
as another storm system over the Gulf next weekend,but currently
not expected to reach hazardous levels with that event. Below
average temperatures will persist for the north and northeast
parts of the state as a quasi-stationary frontal boundary will
remain draped across the Interior for most of the forecast period.
Temperatures are generally expected to be below average with the
Arctic surface high continuing to govern the overall weather
pattern.

Campbell

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