Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
646 PM EST Sun Nov 22 2020
Valid 12Z Thu Nov 26 2020 - 12Z Mon Nov 30 2020
...Continued stormy pattern next week...
...Overview and Guidance/Predictability Assessment...
A series of storms will pass through the region next/weekend as
the overall patterns remains amplified and progressive. In
general, the 12Z guidance has locked onto the overall pattern and
evolution through the extended period however there is some spread
that develops upstream that may affect the timing/location late in
the period. As a whole, the slightly slowing trend has continued
but the flow continues to be progressive. The preferred blend for
this issuance comprised of the 12Z ECWMF/GFS/CMC/UKMET through
Friday, then adding increasing amounts of the ensemble means
through the weekend. Given the spread, consensus depicts the front
to move into the Gulf then Panhandle later next weekend.
...Weather/Threats Highlights...
The leading system along western Alaska/Y-K Delta/AK Pen will
spread modest precipitation, locally heavy at times, along Kodiak
across the southern Kenai Peninsula as the frontal boundary moves
toward the East. Triple point will take aim on the northern
Panhandle where precipitation should maximize around Yakutat
before spreading down the Panhandle as the warm front comes ashore
and weakens. Friday into Saturday, the next system in the Bering
will spread rain/snow/wind across the Aleutians to southwestern
Alaska as the parent low may slowly decay over Bristol Bay to the
AK Pen. The amount and placement of where the associated
precipitation occurs is a bit uncertain as the models differ on
the amount of forcing over water vs land and moisture influx.
Southern to southeastern-facing areas would be favored as is
typical for this evolution. This includes the western side of Cook
Inlet and southeastern Kenai, where several inches of
precipitation are possible. Temperatures will remain well above
normal along northern areas thanks to upper ridging and above
normal lower level temperatures, extending along
western/southwestern areas as well. Southeastern portion of the
mainland into the Panhandle will see varied temperatures within
several degrees of typical late November values.
Campbell
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
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