Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
641 PM EDT Fri Apr 24 2020
Valid 12Z Tue Apr 28 2020 - 12Z Sat May 02 2020
...Guidance/Predictability Assessment...
Upper pattern across Alaska during the extended forecast period
shows ridging near the Bering Strait slowly migrating toward
northwestern Alaska as a trough digs southward into Southcentral
late Tue into Wed. Additional troughing out of the Bering is
forecast to move eastward toward Bristol Bay by next weekend. The
12Z GFS/ECMWF showed relatively good consensus with the ensemble
means during the period, and a blend of these solutions was used
as a forecast starting point. This blend maintained good forecast
continuity but with more amplitude than 24 hrs ago.
Western Aleutian system on Tue will likely split to the southeast
as its old parent low weakens through the week. That system to the
south may try to lift back toward the southern Panhandle by the
end of the period. Over the Interior, a deeper trough compared to
previous forecasts indicate another shot of cooler air all the way
to the Gulf, though moderating, with high pressure in its wake
moving into far northwestern Canada. Lingering troughing in the
Bering may support another front but for now only depicted a
surface trough across the islands.
...Weather/Threats Highlights...
After a lead-in system in the Gulf Mon, another one will bring
additional precipitation/winds to the Panhandle on Tue with
perhaps a brief break before yet more rain/snow Thu with a surface
trough. The Interior, by contrast, will be much drier after the
front sinks southward and dissipates. Additional lighter rain is
expected over the Aleutians later in the week after the first
system, with more appreciable rainfall, slips to the southeast.
After a cooler than normal period at the start of the week over
most of the mainland, temperatures will moderate back to within
several degrees of normal for most of the state with the better
chance of above average temperatures near the Bering Sea.
Fracasso
Additional 3-7 Day Hazard information can be found on the WPC
medium range hazards chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php
Hazards:
No significant hazards are expected over Alaska during this
forecast period.
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