986
FXAK02 KWNH 080000
PMDAK

Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
659 PM EST Tue Jan 7 2025

Valid 12Z Sat Jan 11 2025 - 12Z Wed Jan 15 2025

***Dangerous storm with high winds and extremely heavy
precipitation for the southern mainland this weekend***


...General Overview and Model Guidance Assessment...

An extremely active weather pattern will continue to make weather
headlines across the Alaska domain for the extended forecast
period as multiple strong low pressure systems from the Gulf
hammer the state.  After a lead surface low and front, the
strongest storm is forecast to arrive late Saturday night into
Sunday, producing strong and potentially damaging winds, very
heavy rain, and prolific snowfall for the southern mainland
mountains.  A dramatic warm-up is also expected across the state
as strong southerly winds advect a maritime air mass well into the
Interior and reaching the Brooks Range, followed by a gradual
cool-down.  A third low pressure system is likely to develop over
the Gulf early next week and track in the general direction of
Prince William Sound and possibly eastward to include the northern
panhandle region.

Overall, the 12Z model guidance suite was in decent synoptic scale
agreement across most of the domain, with some minor timing issues
noted for the weekend.  There has been a slight northwestward
trend with the big surface low on Sunday compared to 24 hours ago,
but otherwise there is good continuity from the previous WPC
forecast.  For the weekend, a general model blend with a little
more weighting to the ECMWF/GFS was incorporated, and then
gradually increased percentages of the EC and GEFS means to about
40-50% by next Wednesday amid growing model spread across the
North Pacific and Gulf of Alaska.

...Weather/Hazards Highlights...

A series of atmospheric river events aimed at the coast from the
eastern Alaska Peninsula/Kodiak Island eastward to the St. Elias
Mountains will result in multiple rounds of very heavy coastal
rain and tremendous snow for the higher mountain ranges through
the upcoming weekend.  It appears likely that 8-12 inches of
liquid equivalent will fall across areas with enhanced upslope
flow, with several feet of snow possible on Sunday and Monday
alone.  Flooding could very well become a problem in some of the
lower elevations with enhanced run-off expected.  Given surface
pressures near or even below 960 mb with the incoming Sunday
storm, storm force winds are a near certainty for the coastal
waters, with some hurricane force wind gusts possible.  This will
result in extremely hazardous marine conditions, and possible
power outages near vulnerable coastal locations.  Temperatures are
expected to be well above normal going into the weekend, with some
record highs possible as readings potentially get close to 40
degrees for portions of the Interior.  These anomalously warm
conditions will likely make it to the Brooks Range, with the North
Slope and the Arctic Coast remaining considerably cooler and
closer to climatology.

Hamrick


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

$$