Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
621 PM EDT Sun Mar 20 2022
Valid 12Z Thu Mar 24 2022 - 12Z Mon Mar 28 2022
...Pattern Overview and Weather/Hazard Highlights...
A closed high/ridge is expected settle over the Arctic Ocean this
period, leaving behind a still generally benign weather pattern
for the North Slope and Alaskan Interior. This is expected to
occur as a persistent closed low/trough centered over the Alaskan
Peninsula to northwest Gulf of Alaska into Friday then reforms and
settles over the south-central Gulf of Alaska. Flow around
associated/deepened low pressure systems may present a lingering
pattern favorable for some periods of moderate precipitation
(coastal rains/terrain snows) from south-central Alaska to the
Southeast Alaskan Panhandle. Meanwhile, there is a growing
guidance signal that deep low genesis with amplified upper trough
energies progressing off eastern Asia this week will track to the
Aleutians next weekend with enhanced winds, rains and waves before
then possibly progressing into the western Gulf of Alaska by early
next week.
...Guidance/Predictability Assessment...
The 12 UTC GFS/ECMWF and GEFS/NAEFS/ECMWF ensemble means are in
slightly better agreement at medium range time scales today.
Forecast spread growth is still problematic over time, still
characteristically with the evolution/track of Pacific/Gulf lows.
Accordingly, favor a blended solution with heavy weighting on the
GFS/ECMWF days 4/5 (Thu/Fri) for better details and then slowly
increasing ensemble mean focus days 6-8 to mitigate the less
predictable forecast components. This overall maintains good WPC
product continuity. However, it should still be noted that a less
likely outlier solution again today from the 12 UTC Canadian
through medium range time scales over the North Pacific does at
minimum provide evidence that guidance may still be sensitive to
initialization data in the energetic flow.
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