Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
657 PM EST Fri Jan 28 2022
Valid 12Z Tue Feb 1 2022 - 12Z Sat Feb 5 2022
...Overview...
The Alaska domain will likely experience a blocky upper level
pattern through the first few days of February with a ridge axis
remaining anchored in place over the eastern Gulf region and also
across eastern Siberia, with a col over western mainland Alaska.
A large upper level gyre is expected just south of the western
Aleutians with multiple shortwaves rotating northward towards the
eastern Aleutians and the Alaska/Kenai peninsulas with several
rounds of rain/snow expected.
...Guidance/Uncertainty Assessment...
Overall, the 12Z guidance and the ensemble means are in relatively
decent agreement on the overall synoptic scale pattern across
mainland Alaska and western Canada through about Thursday.
Similar to the past few days, the greatest model and forecast
uncertainty resides over the Bering, Aleutians, and North Pacific
with multiple shortwave perturbations pivoting around a large
scale upper level gyre, with significant timing differences with
the individual shortwaves as they lift northward over the
Aleutians and then the Bering. A weaker disturbance makes it
farther east over the northern Gulf region by the middle of next
week, and the deterministic guidance supports this scenario.
Given the model uncertainties over the Bering/Aleutians later in
the forecast period, an ensemble mean approach appears prudent as
a starting point for now.
...Weather/Hazard Highlights...
Arctic high pressure slowly weakens during the medium range
period, but keeps most of mainland Alaska dry and cold. Snow
showers and gusty winds are likely for the southern coast from the
Kenai Peninsula to the southeast panhandle as a weak low pressure
system develops along a stationary boundary over the northern
Gulf. Some of this snow could be heavy at times on Thursday with
greater onshore flow expected.
Meanwhile, a few storm systems are expected to bring the potential
for periods of wet and windy weather to the Aleutians through this
period. Most of the Interior should be near to below average for
temperatures, and generally above average for south-central Alaska
and the Aleutians.
Hamrick
Hazards:
- Heavy precipitation across portions of the Alaska Panhandle and
mainland Alaska, Thu-Fri, Feb 3-Feb 4.
- Heavy precipitation across portions of mainland Alaska and the
Aleutians, Mon-Thu, Jan 31-Feb 3.
- High winds across portions of the Aleutians, Mon-Wed, Jan 31-Feb
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