Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
620 PM EST Fri Feb 16 2024
Valid 12Z Tue Feb 20 2024 - 12Z Sat Feb 24 2024
...Stormy Bering Sea/Aleutians to Gulf of Alaska Pattern with a
Heavy Precipitation focus from South-Central to Southeast Alaska...
...Guidance Evaluation and Preferences...
The 12 UTC GFS/ECMWF/UKMET/Canadian model solutions seem
reasonably well clustered valid Tuesday into Thursday and enjoy
good ensemble support. The GEFS/ECMWF ensemble means remain
compatible with the GFS/ECMWF later next week to maintain detail
with a series of deep and dynamic storms amid slowly growing
forecast spread. A composite maintains good WPC product continuity
in a pattern with seemingly rising predictability as forecast
spread has trended downward over the last few guidance cycles.
...Pattern Overview and Weather/Hazards Highlights...
Energetic shortwave energies aloft flowing around the
southern/eastern side of a dominant closed upper trough/low
posiiton over the Bering Sea/Aleutians will keep a lead north
Pacific to western Alaska and especially energetic split storm
track over the Gulf of Alaska active with highly unsettled/gusty
and wet conditions. These will offer a protracted maritime threat.
Deepened lows and long fetch moisture/atmospheric rivers will
enhance precipitation into the Alaska Peninsula/Kodiak Island, and
more earnestly from South-Central to Southeast Alaska over time,
increasingly working into a lead upper ridge. These organized
systems will tend to weaken, but remain active, as they reach the
coast given the upper ridging lingering downstream up into the
Mainland. The heavy precipitation threat may be invigirated into
middle to later next week with deeper/larger low approach.
Meanwhile, the Aleutians will see periods of precipitation and
strong/gusty winds, especially through next midweek. Much of
interior Mainland Alaska should be generally dry next week, albeit
with periodic moderate precipitation into Southwest Alaska as
supporting upper energies work on the periphery of the downstream
upper ridge position. In this pattern, locally gusty to strong
winds may also act to forcably blow around snows up through
western to Northwest Alaska as energies lift poleward.
Initial upper ridging, and then continued Pacific influence even
with some erosion of the ridge, will favor above normal
temperatures across most of the state. Expect the greatest
anomalies to be in the western to northern parts of the mainland,
with values upward to 30 degrees milder than normal lingering into
early next week. Some cooling will be possible next week, but
still with above normal anomalies. Some pockets of near to
slightly below normal temperatures will be possible over the
eastern Interior and mostly for daytime highs over portions of the
Panhandle/Aleutians.
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