Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
703 PM EST Wed Jan 25 2023
Valid 12Z Mon Jan 30 2023 - 12Z Fri Feb 03 2023
...Much milder than normal temperatures with periods of snow
across the western mainland late this week to early next week...
...Overview with Model Guidance/Predictability Assessment...
While outbreaks of frigid air from Siberia bring snowy conditions
across Japan, much of Alaska will be under the influence of an
anomalously strong upper ridge through the medium-range period
especially this weekend. Multiple disturbances moving across the
northern Pacific will have a hard time breaking through the strong
and anomalous ridge. Nevertheless, a few shortwaves are forecast
to either pinch off or ride the top of the ridge and then move
across northern Alaska. There is decent model agreement that one
such shortwave will deliver a period of snow this weekend across
northwestern Alaska and possibly into the interior sections
afterwards. Farther south, unsettled weather will likely prevail
across the Aleutians, the Alaska Peninsula and into the western
mainland as disturbances blocked by the strong ridge in the
Pacific turn north toward the Aleutians. Periods of precipitation
and gusty winds can be expected for these areas but the
precipitation is not expected to be excessive as the strong ridge
will effectively weaken the disturbances. Meanwhile, the
Panhandle will remain dry under the ridge axis through the weekend
and into early next week but the cumulative effects of multiple
disturbances moving across the Pacific will gradually erode the
ridge, leading to an increasing chance of precipitation across the
southern coastline and into the Panhandle as next week progresses.
Above average temperatures will abound especially over the western
mainland under the ridge. It generally remains the case that upper
ridging becoming established into the mainland should help
moderate temperatures to well above normal across much of the
state, with possible +30F anomalies for parts of the northwestern
mainland by early next week. Temperatures could warm above the
freezing mark in the southwestern mainland/Bristol Bay area, quite
a change from current conditions. There could be impacts from
snowmelt with these above freezing temperatures, and especially if
precipitation falls as rain or freezing rain there due to the
relative warmth. This is a possibility late week as precipitation
crosses the Aleutians/Alaska Peninsula as well as some possibly
gusty winds along a front stemming from the western Bering low,
which potentially makes its way into the western mainland, though
the impacts farther east are less certain.
Given above average agreement depicted by the model ensemble
means, the WPC medium-range forecasts were based on a blend of 40%
from the 12Z GFS/GEFS, 40% from the 00Z/12Z EC/EC mean, and 20%
from the 12Z CMC/CMC mean, transitioning to mostly a blend of the
ensemble means by Day 7 & 8.
Kong
Hazards:
- Much above normal temperatures across portions of mainland
Alaska, Fri-Mon, Jan 27-Jan 30.
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
Hazards:
- Heavy precipitation across portions of mainland Alaska and the
Aleutians, Thu-Fri, Jan 26-Jan 27.
- Much above normal temperatures across portions of mainland
Alaska, Fri-Sun, Jan 27-Jan 29.
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