Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
458 PM EST Sun Feb 07 2021
Valid 12Z Thu Feb 11 2021 - 12Z Mon Feb 15 2021
...Overview and Guidance/Uncertainty Assessment...
A deep upper level low is expected to be in place northwest of the
Arctic Coast on Thursday. With this low lifting northward over
the Arctic Ocean by the weekend, a ridge axis is expected to build
in over the state from the North Pacific. Meanwhile, a stormy
weather pattern appears likely across the southern Bering Sea and
the Aleutians as a couple of Pacific storm systems pass through
that region as they rotate around a broader upper level gyre.
The model guidance has come into better synoptic scale agreement
compared to yesterday, with the greatest model differences related
to the evolution of the mid-upper level ridge over the mainland,
and the individual shortwaves pivoting around the main upper level
low over the western Aleutians. There was a slightly greater
weighting towards the 12Z ECMWF/00Z EC mean as a starting point in
the forecast process, along with some of the 12Z GFS/CMC.
...Weather/Hazards Highlights...
The frigid temperatures during the short range forecast period are
forecast to moderate by Thursday as the potent upper level and
arctic surface high retreat, and broad upper level ridging builds
back in across the state. The coldest readings will likely be
across eastern portions of the Interior, while warm air advection
is more pronounced over the western half of the state. Periods of
coastal rain and mountain snow are likely from the Kenai Peninsula
to the Fox Islands, and there is a decent model signal for 1 to 3
inch QPF here during this forecast period. Elsewhere, some snow
showers are possible across the northwestern quadrant of the state
owing to the warm air advection, and periods of strong winds are
likely for much of the Aleutians and the Bering Sea region as an
unsettled weather pattern sets in with a couple of low pressure
systems.
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
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