Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
720 PM EDT Sat Oct 29 2022
Valid 12Z Wed Nov 02 2022 - 12Z Sun Nov 06 2022
...Overview...
The weather pattern is expected to remain rather active across the
southern portions of the state for much of the period. The start
of the period features a now phased surface low in the Bering Sea,
with snow and gusty winds likely across portions of Western
Alaska. Around Wednesday-Thursday next week, and a new triple
point low is likely to develop over the northern Gulf (and
shifting south with time) that could produce an atmospheric river
event for the southeast Panhandle region. A more amplified upper
level pattern will build over the domain later next week and
weekend with troughing progressing through Alaska, and ridging
building over the Bering.
...Guidance/Predictability Assessment and Preferences...
The latest model guidance continues to show timing/placement
differences as the period begins Tuesday with the surface low in
the Bering Sea. GFS is west, UKMET east, CMC and ECMWF more
solidly in the middle of the two. A blend of the deterministic
solutions (with some preference towards the middle ground CMC and
ECMWF) seemed to give a good starting point both with placement
and strength. After Wednesday, a new triple point redevelopment
low should form in the northern Gulf with good agreement in the
models that this drop south and east along the Panhandle with
time. The pattern should trend more amplified by late week with
ridging building over the Bering/Aleutians and eventually western
Alaska next weekend. The guidance agrees high pressure should take
hold over much of at least southern Alaska but there are timing
differences well upstream which impacts strength of the ridge over
the Bering and northwest Alaska. A trend towards the ensemble
means seemed to mitigate some of the late period noise.
...Weather/Hazards Highlights...
The Bering Sea low will be the main feature causing significant
weather as the period begins. The tight pressure gradient with the
low will cause concerns for strong winds across the southwestern
mainland with the potential for some blizzard conditions as well.
Depending on exact system strength (which still shows some degree
of uncertainty), coastal flooding could be a hazard. Attention
then turns to the southern mainland coast and the Panhandle region
as an atmospheric river event appears set to develop and produce
very heavy mountain snow and a few inches of rain near the coastal
areas for the Thursday-Saturday time period, shifting southward
with time. On the north side of the low, gusty northerly winds may
create a high wind concern across portions of the Panhandle next
weekend, even after much of the rain moves through. 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.
Santorelli
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