Alaska Extended Forecast Discussion
National Weather Service College Park MD
753 PM EDT Thu May 22 2025
Valid 12Z Mon 26 May 2025 - 12Z Fri 30 May 2025
...General Overview...
The southern portions of Alaska will continue to remain rather
unsettled given the time of year with periods of rainfall likely
each day from the Kenai Peninsula eastward to the southeast
Panhandle region. A weakening low pressure system this weekend
will give way to an incoming low from the Bering that will set up
over the central Gulf through the middle of next week, with moist
onshore flow. Meanwhile, an arctic trough will brush by the
northern third of the state through Tuesday and a weak upper
ridge axis across the Interior, where scattered showers and
thunderstorms are likely.
...Guidance Evaluation and Preferences...
The 12Z model guidance suite features good overall agreement
across the Alaska domain for the beginning of next week, and
improved depiction of the arctic shortwave and front north of the
Brooks Range, although the GFS is more amplified that the model
consensus across this region. The guidance has also come into
better agreement on a reinforcing trough/shortwave behind the
Bering Sea low that enters the Gulf, which will give the low over
the Gulf more staying power. The ensemble means were increased to
about half by next Thursday/Friday.
...Weather/Hazards Highlights...
Periods of rain and high mountain snow are expected from the
Alaska/Kenai Peninsulas to the southeast Panhandle region, with
the greatest coverage and intensity expected from Juneau and
points south. A heavy rain area remains depicted in the WPC
medium range hazards graphic for the 25th to the 28th given how
late in the season this is, and the duration of the rainfall
expected, even though it will not be as heavy as many early season
events. The highest QPF is likely to be south of the Sitka area
based on the latest model guidance. Farther inland across the
Interior, scattered afternoon and evening thunderstorms are likely
to develop in the presence of an unstable airmass, mainly between
Anchorage and Fairbanks. Lightning strikes from these storms may
increase the threat of wildfires in the region.
Temperatures overall are expected to be near to slightly above
average by late May standards across the central and southern
mainland, and slightly below north of the Brooks Range. Cooler
conditions are also likely for the coastal areas and the near
shore islands owing to increased cloud cover and rainfall.
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