Alaska Extended Forecast Discussion
National Weather Service College Park MD
449 PM EDT Mon May 19 2025
Valid 12Z Fri 23 May 2025 - 12Z Tue 27 May 2025
...Overview...
Upper pattern over the high latitudes 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 near normal temperatures and
intermittent chances of rain for the southern/coastal portions of
the state. With a storm track from the Bering to the Gulf, the
best moisture plume should stay south of the Panhandle.
...Guidance Evaluation and Preferences...
The ensembles remain in good agreement overall but struggle with
timing of individual systems (to be expected). The ECMWF AI
ensembles were just a bit faster with the flow than the
operational version, which has been the case for the past day or
so. The deterministic models have trended a bit quicker overall as
well, and mostly clustered with the ensemble consensus. The 12Z
ECMWF and Canadian were a better fit than the GFS for days 6-8,
but otherwise a blended solution sufficed.
...Weather/Hazards Highlights...
Weak troughing over the mainland may give way to some weaker
ridging, allowing temperatures to moderate just a bit, depending
on more uncertain Arctic shortwaves. Partly to mostly cloudy skies
and scattered showers/storms are possible this period over the
interior. More focused rainfall can be expected over the Aleutians
with each passing system and then along the northern Gulf Coast
into the Panhandle. The amount of rainfall will depend on how
close the parent low wobbles northward. Rainfall should be on the
lighter side with any surge in mid-latitude moisture aimed into
central/southern BC. Thus, no hazards were drawn on the day 3-7
hazards map.
Fracasso
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