Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
525 PM EST Fri Nov 19 2021
Valid 12Z Tue Nov 23 2021 - 12Z Sat Nov 27 2021
...Below normal temperatures, high winds and heavy precipitation
expected across portions of Alaska through the medium range
period...
...Overview and Guidance Evaluation/Preferences...
In general, the model guidance agrees with a longwave trough over
parts of the state with multiple impulses through the extended.
However, they continue to struggle with resolving the evolution of
each individual lows but they all favor a low track toward the
Kenai peninsula, especially by the end of the extended forecast.
The means continue to dampen this noise therefore were favored in
the blend for the entire extended periods. Initially the mean
accounted for roughly 20% of the forecast and increased to nearly
40% by the end, otherwise WPC utilized a combination of the 12
ECWMF/CMC and the 06/12Z GFS.
...Weather/Hazard Highlights...
This persistent pattern will keep cold air settled in over much of
the state for at least a few more days. The North Slope will
likely remain near, or briefly above seasonal normal through the
extended period however daily readings as much as 20-30+ degrees
below normal can be expected. Much of the Interior will also have
drier conditions while there will be multiple rounds of
precipitation, possibly heavy at times, across the Aleutian Chain,
the southern coast and the Panhandle. Stronger winds will
accompany each low pressure system and may be observed across the
southern part of the state. Higher wave heights can also be
expected for coastal areas of the Panhandle.
Campbell
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
- Heavy precipitation across portions of the Alaska Panhandle and
mainland Alaska, Wed-Fri, Nov 24-Nov 26.
- Much below normal temperatures across portions of mainland
Alaska, Mon-Wed, Nov 22-Nov 24.
- High significant wave heights for coastal portions of the Alaska
Panhandle, Thu-Fri, Nov 25-Nov 26.
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