Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
727 PM EST Wed Feb 3 2021
Valid 12Z Mon Feb 8 2021 - 12Z Fri Feb 12 2021
...Overview and Guidance/Uncertainty Assessment...
An upper level low that is expected to initially be over far
northwestern Canada on Sunday is expected to slowly settle in over
central and northern Alaska by the middle to end of next week.
This will tend to set up a block pattern across the Alaska region
for the medium range period. Meanwhile, a narrow ridge axis will
likely exist across the Aleutians and Bering Sea region. Surface
low pressure is expected to persist over the norther Gulf of
Alaska with multiple shortwaves pivoting around the main upper low
over the mainland. The 12Z CMC takes the upper low farther south
across the Interior region, whilst the 18Z GFS/GEFS mean keep the
low just north of the Arctic Coast. Elsewhere, there are modest
model differences with the overall synoptic scale pattern, and
incorporating the CMC/ECMWF/GFS along with some of the ensemble
means served as a good starting point, along with some of
yesterday's continuity.
...Weather/Hazards Highlights...
Persistent low pressure over the Gulf of Alaska will tend to focus
periods of precipitation across the southeastern coast and the
southeastern Panhandle through the upcoming week. There is
increasing uncertainty over precipitation intensity over this
area, depending on specifics of the upper low/trough that moves
across the mainland. Current guidance preferences would yield
light-moderate activity for most of this time period. One or more
features lifting up the western side of upper ridging may support
episodes of precipitation/brisk winds over portions of the
Aleutians and southwestern half of the Bering Sea. 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.
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, Sat-Wed, Feb 6-Feb 10.
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