Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
602 PM EST Sat Jan 08 2022
Valid 12Z Wed Jan 12 2022 - 12Z Sun Jan 16 2022
...Guidance/Uncertainty assessment and Weather Pattern/Hazard
Highlights...
A composite of the 12 UTC GFS/ECMWF/UKMET/Canadian tends to
mitigate the less predictable smaller scale differences in
otherwise reasonably well clustered solutions days 4/5
(Wednesday/Thursday).Â
Guidance agrees that an amplified Arctic stream upper trough will
dig and settle over the North Slope/Brooks Range to offer some
cooling and snow potential. A warm and stable upper ridge is
meanwhile expected to build northwestward from western Canada into
Interior Alaska and eventually the North Slope, well in advance of
a stormy maritime pattern into the North Pacific/Gulf of Alaska.
Guidance differences become more problematic on days 6-8
(Friday-next weekend) with varied embedded systems within the
models, especially with interaction from a series of Gulf of
Alaskan lows into the lead upper ridge from western Canada into
the Alaskan mainland. A strong ridge favors heavy precipitation
into the AKpen/south-central AK (GFS/Canadian), while having more
system energies work into the ridge would increasingly shift
precipitation focus across south-central to Southeast AK
(ECMWF).ÂThe 12 UTC GEFS/NAEFS/ECMWF ensemble means however are
well clustered days 6-8. A preferred composite maintains a
decently amplified upper ridge that seems most reasonable
considering the recent blocky nature of flow. This would favor a
south-central AK coastal precipitation focus whose threat along
with enhanced wind flow may be maximized Thursday/Friday with
deepened Gulf low approach. Overall, WPC product continuity is
well maintained with this strategy.
Schichtel
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