Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
630 PM EST Fri Dec 27 2024
Valid 12Z Tue Dec 31 2024 - 12Z Sat Jan 04 2025
...Overview with Guidance Evaluation and Preferences...
Models and ensemble means agree well that the medium-range
forecast period for the Alaskan domain will feature a tilted omega
blocking pattern gradually lifting north across mainland Alaska
and evolve into a closed high over the Arctic Ocean heading into
the first few days of the year 2025. Much of mainland Alaska will
then be under an upper-level col while the main cyclone tracks
will remain well south of the Gulf of Alaska, coupled with the
tendency for the individual cyclones to weaken as they head toward
the Gulf. A deeper cyclone will appear to slide south of the
Aleutians through the latter half of next week, likely broadening
and strengthening the northeasterly flow across the Bering Sea and
through the Aleutians. The WPC forecast was based on a consensus
blend of the 12Z GFS/GEFS, 12Z ECMWF and 00Z/12Z EC mean, and the
12Z CMC/CMC mean. This solution maintained good continuity with
the previous WPC forecast package. The 06Z GFS did not appear to
agree with the rest of the guidance regarding the individual
cyclone tracks and thus was not included in the blend.
...Weather/Hazards Highlights...
No hazardous weather is anticipated for the Alaskan domain through
the medium-range forecast period. Much of mainland Alaska will be
under a dry and persistent east to northeasterly flow near the
surface with only modest amounts of precipitation along the
southern coastlines including the Panhandle and the Aleutians. A
stronger low pressure system edging closer toward the Gulf of
Alaska could provide a period of gustier winds to the southeastern
coastal sections of the Alaska Peninsula and Kodiak Island on
Tuesday before sliding off to the east and weakens. Some increase
in precipitation chances and amounts can be expected for the
western and central Aleutians by the latter half of next week when
a deeper cyclone is predicted to slide to the south.
After recovering from temperatures well below normal levels early
in the week across the North Slope, a persistent east to
northeasterly flow being fed by a strengthening surface high
pressure system centered over the Arctic Ocean (with central
pressure possibly up to 1050 mb) late next week will keep
temperatures below normal for much of mainland Alaska. Above
normal temperatures will be confined farther south across the
Alaska Peninsula, all of the Aleutians, and along the southern
coastlines including the Alaska Panhandle.
Kong
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