Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
656 PM EST Mon Jan 1 2024
Valid 12Z Fri Jan 5 2024 - 12Z Tue Jan 9 2024
***Conditions remain quite stormy for the Aleutians and western
Alaska going into next weekend***
...General Overview...
The intense low pressure system expected to hammer the Aleutians
in the short range forecast period will be undergoing a steady
weakening trend by Friday as it slowly lifts northward along the
western Alaska coast. Unfortunately, the break in the bad weather
is short-lived as the next strong northern Pacific storm system
approaches the central Aleutians on Saturday with widespread gale
to storm force winds. It appears this low will be a little weaker
and track more to the west compared to the short range event. An
influx of moisture oriented toward the south-central Alaska coast
is expected to produce copious coastal rain and mountain snow from
the Alaska Peninsula to the Chugach Mountains. A potential third
system lurks on the distant horizon for early next week.
...Guidance Evaluation/Preferences...
The 12Z model guidance suite is in good overall synoptic scale
agreement across most of the Alaska domain on Friday, with the
greatest differences centered over the southern Gulf regarding the
placement of a relatively weak low pressure system. With the
intense low approaching the Aleutians on Saturday, the 12Z GFS is
near the consensus of the guidance, whereas the UKMET/ECMWF is
southeast and the CMC northwest. The guidance maintains a near
960mb low across the central Bering on Sunday with a weakening
trend after that. However, model spread becomes substantial with
the third system by next Tuesday, with the GFS showing a much
stronger storm compared to the CMC/ECMWF, and big timing
differences as well. The use of the ensemble means accounted for
about 40-50% of the blend going into early next week.
...Weather/Hazards Highlights...
The main weather hazard during this time period will be episodes
of high winds across both the Arctic Coast/North Slope region and
also for the Aleutians where a strong pressure gradient will be in
place on Thursday and into early Friday, and again for the
Aleutians on Saturday as the next storm moves in. Wind gusts in
excess of 60 mph are likely for these areas, and this will likely
result in some instances of coastal flooding for portions of
southwestern mainland Alaska and the Aleutians. Ground blizzard
conditions are expected for much of the Arctic Coast region
mid-late week. In terms of precipitation, very heavy mountain
snow is expected from the Kenai Peninsula to the Chugach
Mountains, and a cold rain near the coast as a plume of Pacific
moisture is advected northward, but most of the Interior and the
North Slope should have little in the way of additional snow.
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