Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
648 PM EST Fri Jan 31 2025
Valid 12Z Tue Feb 4 2025 - 12Z Sat Feb 8 2025
...Synoptic Overview...
The main theme for the extended forecast period will be a negative
EPO pattern featured by a strong mid-upper level ridge axis
extending north from the Gulf and across the mainland. This
should initially be a closed upper high near the Alaska Peninsula
on Tuesday and this slowly sinks to the south through the end of
the week, with the core of the ridge over the central Gulf by
Friday. Meanwhile, shortwave energy and accompanying surface lows
are expected to track around the western periphery of that ridge
and cross the central/western Aleutians into the Bering Sea. This
synoptic set-up will tend to maintain above normal temperatures
and mostly dry conditions across the majority of the state through
next Saturday.
...Guidance Evaluation and Preferences...
The 12Z model guidance agrees well on most facets of the forecast
to begin the period Tuesday, with the best agreement on the
strength and position of the main upper ridge across the state.
The region with greatest uncertainty moving forward is across the
western portion of the domain to include the Aleutians and the
Bering Sea where the main storm track will be. The ECMWF and GFS
are among the stronger solutions with a storm system crossing the
Aleutians Thursday, but things become more uncertain with
shortwave energy behind that, with the ECMWF/CMC portraying a
stronger second low in contrast to a weaker GFS solution. By next
Saturday, there is still good overall model support for the ridge
axis extending north across the mainland, although the ensemble
means are a little west with the ridge axis compared to the
deterministic guidance. Much greater uncertainty resides across
the Bering and North Pacific however. The ensemble means were
increased to about half by the Friday/Saturday time period.
...Weather/Hazards Highlights...
The weather is forecast to be relatively pleasant for this time of
year with the upper high/ridge and surface high governing the
overall weather pattern. The southern half of the state is
expected to be mainly on the dry side and offshore flow along the
southern coastal areas should keep precipitation coverage greatly
reduced. There may be an increase in showers across portions of
the Alaska Peninsula and eastern Aleutians as the storm track
gradually moves farther east, with most of the rainfall confined
to the central Aleutians and offshore areas. There may be some
light snow or mixed precipitation across portions of northwestern
Alaska through the middle of the week.
Temperatures are expected to be pleasant by early February
standards across the mainland and especially so across the North
Slope and Brooks Range with highs potential running 30 degrees
above seasonal averages. A few record highs are within the realm
of possibility. A slight cool-down is probable going into the end
of the week, but still above normal in most cases. There may be
some Interior valleys that have surface inversions that don't mix
out, and those areas would still remain rather cold. The
Southeast Panhandle region should also be colder than average most
days with an arctic surface high situated over southwestern Canada.
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