Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
559 PM EDT Wed Mar 23 2022
Valid 12Z Sun Mar 27 2022 - 12Z Thu Mar 31 2022
...Pattern Overview and Weather/Hazard Highlights...
An amplifying upper trough south of the Aleutians and then
entering the Gulf by early next week will sustain the development
of a well organized surface low. This will approach the southeast
Alaska mainland and then the eastern panhandle region with the
potential for heavy coastal rain and mountain snow. A ridge axis
builds northward across western Alaska and adjacent portions of
the Bering and the Aleutians ahead of the next storm system
approaching the Aleutians by the middle of next week, with more
rain and windy conditions likely.
The developing Gulf low for early next week will likely have gusty
winds, moderate to heavy rain, mountain snow, and even high waves
across the southeast panhandle region for next Monday and into
Wednesday. Strong onshore flow that is orthogonal to the terrain
will enhance precipitation totals for the windward areas. In
terms of temperatures, most of the mainland should enjoy readings
above average through the weekend, followed by a return to
seasonal to below average readings for some areas through next
Wednesday. It will remain quite cold for locations north of the
Brooks Range.
...Guidance/Predictability Assessment...
The 12Z UKMET/CMC/ECMWF guidance suite is in good agreement on the
overall synoptic scale pattern through the beginning of next week.
The past few runs of the GFS have been consistently displaced
well to the southwest of the model consensus regarding the strong
Gulf low that will be affecting the southern coastal areas, and is
also not supported by its own GEFS ensemble mean. This is a
result of an upper trough axis that is displaced to the west of
the model/ensemble consensus. In addition, the GFS becomes much
more amplified with the next storm system emerging from the Bering
Sea/Aleutians region by next Wednesday/Thursday. The
CMC/ECMWF/UKMET and the ensemble means all suggest a solution
closer to the south-central Alaska coast for the Gulf of Alaska
system, and thus a non-GFS blend will be preferred. There is a
gradual increase in the ensemble means for the second half of the
forecast period to account for normal levels of increasing
uncertainty.
Hamrick
Hazards:
- Heavy precipitation across portions of the Alaska Panhandle,
Mon-Wed, Mar 28-Mar 30.
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