Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
754 PM EDT Sat May 3 2025
Valid 12Z Wed 7 May 2025 - 12Z Sun 11 May 2025
...General Overview...
The strong low pressure system over the Gulf should be weakening
by the beginning of the forecast period Wednesday, with a
stationary frontal boundary draped across the Interior. This low
weakens further going into Friday, while an organizing storm
system approaches from the west and is in the vicinity of the
Aleutians by next weekend. Meanwhile, the strong Arctic surface
high across northern Alaska weakens through time.
...Guidance/Predictability Assessment...
The 12Z guidance is fairly well clustered for the middle of the
week across mainland Alaska and with the weakening surface low
over the Gulf, so a general deterministic mode blend works as a
starting point in the forecast process. Looking ahead to the end
of the week, timing and latitudinal differences increase with the
next incoming storm system across the Aleutians, with the GFS/GEFS
generally more progressive, and the ECENS slower than the model
consensus, including the operational ECMWF. Model spread by next
weekend is quite pronounced across the southern half of the domain
to include the maritime areas with low confidence in any one
particular solution, so more of an ensemble mean approach is best
for this time range.
...Weather/Hazards Highlights...
Winds and precipitation are expected to decrease across the
southern coastal areas by Wednesday. Higher elevations inland will
have snow during this period. Mostly cloudy conditions will
prevail as a synoptic scale trough and embedded upper low will
remain over the Gulf. Below average temperatures across portions
of the Interior will begin to moderate closer to seasonal averages
by the end of the extended period as the Arctic high weakens and
the easterly winds decrease.
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