Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
515 PM EST Tue Feb 15 2022
Valid 12Z Sat Feb 19 2022 - 12Z Wed Feb 23 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 central
Aleutians and then the Bering through the upcoming weekend, and a
trough likely builds in across the Interior by next
Tuesday/Wednesday as the ridge axis likely gets suppressed to the
south.
...Guidance/Predictability Assessment...
The 12Z deterministic guidance and the ensemble means have a good
overall depiction of the synoptic scale pattern through about
Monday. By Monday evening into the middle of next week, the
models diverge on the eventual breakdown of the Gulf ridge and
intrusion of shortwave energy from the Bering. The most apparent
differences reside across the northern Bering and western Alaska,
where the GFS/GEFS are more pronounced with a narrow ridge axis
extending to far eastern Siberia, whereas the ECMWF/CMC are
displace more to the west with that same ridge and favors more of
a trough over the western coast of Alaska. By 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, but differ more across the Alaska mainland with the GFS
being more robust with the shortwave across the southern mainland
coast.
Taking these considerations into account, the WPC fronts/pressures
forecast is primarily derived from a CMC/ECMWF/GFS/some ECENS
blend through Monday, and then primarily GEFS/ECENS/some GFS and
ECMWF for next Tuesday and Wednesday.
...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. The heaviest rainfall is likely
for portions of the Aleutians and the southern coast, 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 the Alaska Panhandle,
Friday, Feb 18.
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