Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
538 PM EST Mon Dec 25 2023
Valid 12Z Fri Dec 29 2023 - 12Z Tue Jan 02 2024
...General Overview/Guidance Evaluation/Preferences...
Initial troughing extending from the Mainland into the Gulf will
weaken/shift east with time, eventually being replaced by a
strengthening ridge next Monday/New Years Day. This blocky ridge
will help keep mean troughing across the Bering Sea with the
general storm track being near/south of the Aleutians and deep
layer moisture flow to be southerly to south-southeasterly
directed into the southern coast/Panhandle region. The first
modestly strong system should affect the AK Peninsula/southern
Coast region on New Years Day, with a second stronger system
towards the west-central Aleutians next Tuesday.
Overall, the latest 12z guidance shows pretty good agreement on
the evolution of the upper pattern, but there remains a lot of
uncertainty in the details involving placement and strength of
individual systems near the Aleutians and weakening as they move
into the Gulf. A general model blend of the deterministic models
seems to provide a good starting point to the forecast, with more
incorporation of the ensemble means by especially the second half
of the period. Overall, this maintains pretty good consistency
with yesterdays WPC AK forecast as well.
...Weather/Hazards Highlights...
The expected flow pattern leads to some confidence in several
inches of precipitation (mostly rain, with snow at the highest
elevations) across the southern extremities of Alaska from the AK
Peninsula eastward to the Panhandle/Southeast associated with
several low pressure systems directing moist southerly flow into
the coastal regions. Precipitation, locally heavy, should
initially focus across the Panhandle/Southeast Alaska next weekend
with a weakening cold front across the region. Showers may
continue into the New Year next week, but should overall dry out
as a ridge builds over the region. The next system approaches the
AK Peninsula region on New Years Day/Monday with possibly heavy
rainfall and gusty winds. Gale to storm-force winds are expected
over the ocean, but colder air over interior Alaska could lead to
periods of enhanced gap winds in favorable spots. This system
should weaken quickly as it pulls north into Mainland Alaska,
while at the same time, a stronger low affects the Aleutians and
eventually again the AK Peninsula/southern Coast. A significant
warming trend will be happening across Alaska through the period.
Temperatures across the south-central into interior Alaska could
be near or below normal Thursday and Friday, but should quickly
warm up to well above normal next weekend and beyond. This equates
to temperatures near or slightly above freezing across the
Peninsula, Southern Coast, and Panhandle.
Santorelli
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