Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
657 PM EST Sat Nov 27 2021
Valid 12Z Wed Dec 01 2021 - 12Z Sun Dec 05 2021
...Well below normal temperatures over southwestern Alaska should
moderate by next weekend...
...Guidance Evaluation/Preferences...
The new model guidance today appears to be compatible with each
other enough through Day 8 that a general model compromise should
offer a good starting point. An even blend of the 12Z GFS/GEFS,
12Z ECMWF/00Z EC mean, together with some contributions from the
12Z CMC/CMC mean was adopted from Days 4 to 6. Higher percentages
from the ensemble means were then used for Days 7 and 8. This
blend yielded a solution quite similar to yesterday's forecasts
with these notable differences: (a) a compact low pressure wave on
Wednesday now tracks just north of the Aleutians instead of to the
south, (b) the next significant frontal system of concern now
moves faster across the Bering Sea next Friday.
...Weather/Hazard Highlights...
An occluded cyclone hovering near the southern coast of Alaska
midweek will likely weaken slowly through the end of the week,
easing the threat of heavy precipitation through the southern
periphery of Alaska and down along the Panhandle. Radiational
cooling will likely keep temperatures much below normal for much
of the southwestern mainland into the latter part of the week
before a series of more energetic frontal systems brings southerly
flow and the possibility of some locally enhanced snowfall with
windy conditions into western Alaska by next weekend. Occasional
rain and gusty winds can be expected farther south along the
Aleutians next weekend.
Kong
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