Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
627 PM EDT Wed Nov 2 2022
Valid 12Z Sun Nov 6 2022 - 12Z Thu Nov 10 2022
...Synoptic Scale Overview...
An impressive upper level ridge and corresponding surface high
will evolve across the mainland with an omega block type pattern
expected to develop going into early next week, with surface
pressures perhaps reaching 1050 mb across portions of the eastern
Interior! There will be some shortwave/frontal passages across
the Aleutians and the Bering, although the eastward progress of
these will be limited by the big high to the east. The ridge will
likely break down some by the end of the forecast period with a
broad trough becoming established just west of the state.
...Guidance/Predictability Assessment and Preferences...
Overall, the model guidance shows fairly good agreement at the
start of the forecast period this weekend, and there is also
strong agreement in the ensemble guidance for the high latitude
ridge axis that develops. The greatest degree of forecast
uncertainty resides west of this ridge across the Bering and the
Aleutians where a few shortwave perturbations will track
northwestward, although none of these appear to be particularly
strong in the guidance at this juncture. Model spread increases
substantially going into the Wednesday and Thursday time period
across the Aleutians and North Pacific. In terms of model
preferences, a multi-deterministic blend sufficed through Monday,
followed by gradually increasing portions of the GEFS/EC means
through the middle of next week.
...Sensible Weather and Potential Hazards...
By this weekend into early next week, high pressure will govern
the weather pattern across much of the mainland with little in the
way of snow or wind for most areas. This will also produce a
strong low level temperature inversion for the central and eastern
Interior valleys, with readings well below typical early November
levels and very little mixing with the warmer air aloft. Some
locations will likely remain subzero for a few days across the
Yukon Flats of the eastern Interior, mainly Sunday and into Monday
before a gradual moderating trend ensues. Northern Alaska may end
up being near or slightly above normal for temperatures where
there will be less of an inversion to deal with north of the
Brooks Range. Across the northwestern mainland coast, high winds
and rough surf are becoming more likely on Sunday as a strong
storm system passes northward across the Arctic Ocean, and then
winds abate going into the beginning of the week. Winds are
expected to abate across the southern coastal areas and the
Panhandle early next week after very windy conditions this weekend.
Hamrick
- High winds across portions of the Alaska Panhandle and southern
mainland Alaska, Sun, Nov 6.
- High winds across portions of southern mainland Alaska, Sat, Nov
5.
- High significant wave heights for coastal portions of
northwestern mainland Alaska, Sun, Nov 6.
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