Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
513 PM EST Fri Feb 5 2021
Valid 12Z Tue Feb 9 2021 - 12Z Sat Feb 13 2021
...Overview and Guidance/Uncertainty Assessment...
An upper level low that is expected to initially be over
northeastern mainland Alaska on Tuesday is expected to slowly
drift westward through the middle of the week. A narrow ridge
axis will likely exist across the Aleutians and Bering Sea region
that extends northward from the North Pacific. There is the
increasing possibility that a strong surface low could affect the
western Aleutians by Wednesday and into Thursday. It is also
interesting to note that a highly anomalous surface high just
north of the Arctic Coast, on the order of 1060+ mb, could come
close to setting high pressure records for Barrow (Utqiagvik). In
terms of the models, the 12Z GFS stood out from the model
consensus by the end of the week with keeping the core of the
upper low farther south across southwestern Alaska, whereas the
CMC/ECMWF and the ensemble means favored a solution closer to the
Arctic Coast. Elsewhere, there are numerous model differences
with the overall synoptic scale pattern with lower than average
forecast confidence by Thursday and beyond, and incorporating the
CMC/ECMWF/some GFS along with some of the ensemble means served as
a good starting point, along with some previous WPC continuity.
...Weather/Hazards Highlights...
Coastal low pressure over the Gulf of Alaska will tend weaken
through Wednesday, and this will focus periods of snow across the
southeastern coast and the southeastern Panhandle. It appears
that the heaviest precipitation is most probable around Wednesday
for this region, and potentially for the central and western
Aleutians depending on the track of the next storm system.
Depending on the eventual strength of that storm, gusty winds
could eventually become a concern, but confidence is currently
limited. Today's guidance preferences would yield mainly light to
moderate activity for most of this time period. In terms of
temperatures, it will likely be bitterly cold across much of
central and northern Alaska with widespread 30 below readings
expected north of the Alaska Range, and perhaps as extreme as 50
below for the normally colder locations.
Hamrick
Additional 3-7 Day Hazard information can be found on the WPC
medium range hazards chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php
Hazards:
- Much below normal temperatures across portions of mainland
Alaska, Sun-Thu, Feb 8-Feb 11.
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