Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
657 PM EST Sat Jan 29 2022
Valid 12Z Wed Feb 2 2022 - 12Z Sun Feb 6 2022
...Overview...
A col will be in place across western Alaska for the middle of the
week with a strong ridge over the Gulf region and eastern Siberia,
and a deep upper low over the western Aleutians and trough over
the Yukon. Multiple shortwaves pivoting around the upper level
gyre will tend to erode the Gulf ridge some, and this will result
in multiple rounds of precipitation for southern coastal areas of
the state, with heaviest rain/snow from the Kenai Peninsula to the
southeast Panhandle.
...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. There was enough agreement among
the UKMET/ECMWF/GFS through early Friday to merit a blend of those
models, along with some of the ECENS mean. 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 governs the weather pattern across the
Interior and 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 onshore flow from
the Gulf and a nearby stationary front keep things unsettled.
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
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