Alaska Extended Forecast Discussion
National Weather Service College Park MD
721 PM EDT Tue May 20 2025

Valid 12Z Sat 24 May 2025 - 12Z Wed 28 May 2025

...Overview...

The upper level pattern over the Alaska domain will feature 
weaker troughing over mainland Alaska and a rather persistent 
upper low in the Gulf. Stronger upper ridging south of the central
Aleutians will eventually relax and stretch westward, further 
allowing troughing in the Bering to reload into the Gulf. The end 
result will be a progressive pattern with temperatures generally
within 10 degrees of climatology, and multiple chances of rain 
for the southern/coastal portions of the state, with the greatest 
coverage across the Panhandle. 


...Guidance Evaluation and Preferences...

The 12Z model guidance suite features decent overall agreement
across the Alaska domain for the upcoming weekend across the Gulf
and the mainland, but more uncertainty than usual for the Bering
with the next storm system moving in. The ensembles show greater
spread with timing and intensity of the low as it crosses the
Bering, and things actually get better defined by late Sunday into
Monday as the low eventually re-forms over the Gulf. There are
also noteworthy model differences across the Arctic with a closed
low north of the Arctic Coast. However, there appeared to be no
major outliers and a general model blend worked through Monday,
followed by gradually increasing percentages of the ensemble means
through the middle of next week.


...Weather/Hazards Highlights...

Periods of rain and high mountain snow are expected from the
Alaska Peninsula to the southeast Panhandle region, with the
greatest coverage and intensity expected from Juneau and points
south. A heavy rain area is delineated in the WPC medium range
hazards graphic for the 24th to the 27th 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.
Farther inland across the Interior, scattered afternoon and
evening thunderstorms are likely to develop in the presence of an
unstable airmass, and 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