Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
549 PM EST Mon Jan 10 2022
Valid 12Z Fri Jan 14 2022 - 12Z Tue Jan 18 2022
...Guidance/Uncertainty Assessment...
Guidance forecast spread has increased a bit since yesterday.
Embedded system continuity is not ideal, but overall spread still
seems manageable with usage of a 12 UTC GFS/ECMWF/UKMET/Canadian
model blend Fri/Sat before transition Sunday to quite compatible
GEFS/NAEFS/ECMWF ensemble means by early next week. Biggest model
differences are in the day 6-8 time frame with the evolution of
upper trough energies over the North Slope/Interior, lead upper
ridging, and with North Pacific and Gulf of AK surface low genesis
and system phasing. Manual adjustments were applied to maintain as
much system depth continuity as feasible consistent with upper
support in a pattern with gradually lowering flow predictability
over time.
...Weather/Hazard Highlights...
Arctic stream upper troughs will settle/dig over
northern/northwest Alaska as additional upper troughing lifts from
the southwest to an also unsettled Interior to support some
scattered snows in a highly complex pattern. There are also
uncertain interactions with a moderating lead lead upper ridge
built northwestward from western Canada into the Interior that
weakens over time. This all occurs over-top a stormy maritime
pattern over the Gulf of Alaska. While multiple systems there are
expected to affect a broad area this period, latest low tracks
seem to best favor the AKpen/Kodiak Island and the Kenai
Peninsula/south-central AK for local terrain enhanced
precipitation/wind Thursday, shifting more into Southeast AK
Friday and Sunday. There also remains some signal in support of
additional strong low genesis and track toward the Aleutians over
the weekend into early next week.
Schichtel
Hazards:
- Heavy precipitation across portions of mainland Alaska, Thu, Jan
13.
- Heavy precipitation across portions of the Alaska Panhandle and
mainland Alaska, Fri, Jan 14 and Sun, Jan 16.
- High winds across portions of mainland Alaska and the Aleutians,
Thu, Jan 13.
- High winds across portions of the Alaska Panhandle, Fri through
Sun, Jan 14, 15, and 16.
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