Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
656 PM EST Wed Feb 16 2022
Valid 12Z Sun Feb 20 2022 - 12Z Thu Feb 24 2022
...Overall weather pattern...
A large surface high in association with a building upper level
ridge axis will be in place over the northeast Pacific and
southern Gulf through early next week, and this ridge axis is well
inland across eastern Alaska by Sunday and Monday. Meanwhile, a
broad upper low and surface low should be over the Bering through
the upcoming weekend, and a weak trough likely builds in across
the northern half of the state by next Tuesday/Wednesday as the
ridge axis likely gets suppressed to the south. A strong low
pressure system then approaches the western Aleutians by the
middle to end of the week.
...Guidance/Predictability Assessment...
The 12Z deterministic guidance and the ensemble means have a
reasonably good overall depiction of the synoptic scale pattern
through about Monday, however the GFS diverges from the consensus
by Monday regarding the placement of the surface low over the
Bering and is much more progressive in lifting this low north
towards the Arctic. There is overall better clustering with the
operational CMC/ECMWF and the ECENS going through the middle of
the week. The UKMET is also closer to these same solutions. By
Wednesday, the CMC is on the strong side with a low developing
south of the Alaska Peninsula, and only has limited ensemble
support. Towards the end of the forecast period next Wednesday,
models are in above average agreement on a big low pressure system
near the far western Aleutians.
Taking these considerations into account, the WPC fronts/pressures
forecast is primarily derived from a CMC/ECMWF/UKMET/some ECENS
blend through Tuesday, and then primarily ECENS/ECMWF/some GEFS
mean for next Wednesday and Thursday.
...Weather/Hazard Highlights...
Multiple rounds of mainly precipitation, primarily in the form of
snow, are likely across central and southern portions of the
mainland through early next week. Some areas may be warm enough
for rain across the lower elevations. The heaviest rainfall is
likely for portions of the Aleutians and the southern mainland,
and strong winds are also possible for the central and eastern
Aleutians as a strong pressure gradient will be in place across
this region.
Most of the state should enjoy a break from the extreme cold with
temperatures generally running above average for most areas along
and south of the Brooks Range, with the southwestern mainland
likely to have the warmest readings this weekend and into Monday
with highs 15 to perhaps 30 degrees above normal. Frigid
conditions will likely continue for the Arctic Coast with flow off
the Arctic Ocean.
Hamrick
Hazards:
- Heavy precipitation across portions of mainland Alaska, Mon, Feb
21.
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