Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
422 PM EST Sat Feb 08 2025
Valid 12Z Wed Feb 12 2025 - 12Z Sun Feb 16 2025
...Guidance Evaluation and Preferences...
Model and ensemble guidance is well clustered in the Wednesday
into Friday time frame with seemingly overall above normal
predictability despite non-traditional flow transition. A 12 UTC
GFS/ECMWF/UKMET/Canadian model composite was preferred for best
detail, albeit with consideration for the smoothing of less
resolved smaller scale system variances. Forecast spread increases
into longer time frames. This is evident most notably with the 12
UTC GFS by then that is an unlikely outlier solution versus the
last few GFS/GEFS runs and other guidance. Opted to instead blend
much more compatible guidance from the GEFS/ECMWF/Canadian
ensemble means with the 12 UTC ECMWF/Canadian models. This
solution also maintains good WPC product continuity.
...Weather/Hazards Highlights...
Amplified upper level flow for Alaska and vicinity will hold
through next midweek as highlighted by mean upper troughing from
the North Pacific into the Bering Sea and downstream upper ridging
from the eastern Gulf of Alaska poleward through the Mainland and
the Arctic Ocean. In this pattern, system energies and weather
focus will lift through the Aleutians and the Bering Sea, with wet
downstream inflow fueling lingering precipitation for the Alaskan
Peninsula/Kodiak Island/Southwest AK. In transitional flow, ample
and unsettling upper trough energy and height falls will
increasingly work over the Interior and North Slope from high
latitudes and Canada to undercut and split the Mainland ridge into
later next week and weekend. This could support scattered enhanced
winds/snows. Meanwhile, an Arctic front on the leading edge of
cold high pressure will push down across the Mainland and focus
some precipitation as limited moisture is squeezed out of the
cooling airmass. The front will eventually settle down into the
Gulf of Alaska and through the already cold Southeast to set-up to
the north of an uncertain approach of a number of possible Pacific
systems slated at this point to likely hold well offshore over the
Gulf this period.
Schichtel
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