Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
611 PM EST Tue Jan 25 2022
Valid 12Z Sat Jan 29 2022 - 12Z Wed Feb 02 2022
...Overview...
Models and ensembles agree in depiction of an Omega block pattern
over the Alaska region during this forecast period that only
modestly degrades into early next week. This will be highlighted
aloft by a far northeast Russia closed upper high to Bering
Sea/Southwest AK ridge sandwiched underneath by upper
troughs/lows. With the latter, favored areas for storm development
in this pattern will be over the Gulf of Alaska where a couple of
systems will bring unsettled weather to Southeast Alaska.
Additionally to the west, a couple of deepened cyclones will
rotate to the Aleutians.
...Guidance/Uncertainty Assessment...
The greatest uncertainties in this pattern result from the details
of the block, especially as you go later in the period. This
results in a rather chaotic array of surface lows near the
Aleutians and also in the Gulf of Alaska. The 12 UTC
GFS/ECMWF/UKMET seem decently clustered Day 4/Sat and a composite
is reasonable. Forecast spread then grows quickly, with only the
12 UTC ECMWF seemingly in line enough with the GEFS/NAEFS/ECMWF
ensemble means into days 5/6 (Sun/Mon) to add a bit more detail
consistent with a pattern with below normal embedded system
predictability. Chaotic and complex system interactions continue
into days 7/8 when the WPC Alaskan medium range product suite was
derived mainly from only the ensemble means.
...Weather/Hazard Highlights...
Arctic high pressure overall holds during the medium range period
to keep most of mainland Alaska dry. Meanwhile, storm systems in
the Gulf will translate to unsettled conditions along the
Southeast coast and Panhandle regions. Moderate to heavy
precipitation there will shift slowly southward this weekend with
conditions tending to dry out by early next week. A decent
pressure gradient along the coast may bring a period of gusty
winds as well to these areas.
A number of storm systems will likely bring periods of wet and
windy weather to the Aleutians through this period, and by
early-mid next week potentially downstream into otherwise
generally benign weather conditions into the AKpen. Temperatures
across most of the state should start out below to much below
normal into the weekend (except the Panhandle), though will ease
with time. By early next week, parts of the Western Alaska and
especially the North Slope may see temperatures rise above normal,
with the Panhandle much below normal.
Schichtel
Hazards:
- Heavy precipitation across portions of the Alaska Panhandle and
mainland Alaska, Fri-Sat, Jan 28-Jan 29.
- High winds across portions of the Alaska Panhandle and mainland
Alaska, Fri, Jan 28.
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