Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
759 PM EDT Fri Oct 28 2022
Valid 12Z Tue Nov 1 2022 - 12Z Sat Nov 5 2022
...Overview...
The weather pattern is expected to remain rather active across the
southern portions of the state for the first few days of November.
A phasing of two separate storm systems (one over the northern
Bering and the other near the central Aleutians early next week)
will likely result in a single and stronger storm that will likely
affect portions of western Alaska with snow and gusty winds, and a
new triple point low is likely to develop over the northern Gulf
by late Wednesday into Thursday/Friday that will likely produce an
atmospheric river event for the southeast Panhandle region. This
will result in a more amplified upper flow pattern with a trough
over Alaska and a ridge over the western Bering.
...Guidance/Predictability Assessment and Preferences...
The latest model guidance is still having some challenges with the
phasing of the two low pressure systems over the Bering and the
Aleutians early next week, and there continues to be significant
run-to-run model variance with the past few runs of the GFS, with
the trend being weaker compared to yesterday's runs. The ECMWF is
still portraying a strong and rather impactful system for
southwestern Alaska, with the ICON model indicating more of a
middle ground solution in terms of system strength. Interestingly
enough, model agreement actually improves some going forward to
Thursday with decent agreement on the new northern Gulf low and
also with the developing upper ridge axis/surface high over the
Aleutians and the Bering. Taking these factors into account, some
WPC continuity was maintained and about half of the deterministic
guidance was used going into the latter half of the forecast
period.
...Weather/Hazards Highlights...
The Bering Sea low will be the main feature causing significant
weather early next week. The tight pressure gradient with the low
will cause concerns for strong winds across the southwestern
mainland with the potential for some blizzard conditions during
the Tuesday-Wednesday time period. If the stronger model
solutions come to pass, then high winds gusting over 40 mph and
even some coastal flooding could result, so this is something that
will continue to be monitored going forward. Attention then turns
to the southern mainland coast and the southeast Panhandle region
as an atmospheric river event will probably develop and produce
very heavy mountain snow and a few inches of rain near the coastal
areas for the Thursday-Saturday time period. In terms of
temperatures, expect most of the central and southern portions of
the state to remain colder than normal, and near normal from the
Brooks Range to the Arctic Coast most days, with sub-freezing high
temperatures expected for most inland areas except for the
Aleutians and the southern coast/Panhandle region.
Hamrick
Hazards:
- High winds across portions of western mainland Alaska, Mon-Wed,
Oct 31-Nov 2.
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