Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
753 PM EDT Mon Jul 29 2024
Valid 12Z Fri Aug 2 2024 - 12Z Tue Aug 6 2024
...General Overview...
An upper trough centered over the northern half of the state late
this week is forecast to lift out, and an amplified upper level
ridge is likely to build over the eastern 2/3rds of the state
going into Sunday and the beginning of next week. This will be in
response to a deep upper level trough/closed low developing over
the western Bering Sea. The result will be a warming trend across
most of the state throughout this forecast period.
...Guidance Evaluation/Preferences...
The 12Z model guidance suite has good overall agreement on the
synoptic scale pattern for the end of the week across the Alaska
mainland, and some minor timing and placement differences with the
upper trough and weak surface low over the Gulf. Looking ahead to
the weekend, the CMC begins to stray from the model consensus
across multiple areas, and it is also stronger and farther east
with the trough axis across the Bering/Aleutians. There was
better agreement among the GFS/ECMWF and their ensemble means, and
the UKMET was also reasonably close through the weekend. There
has definitely been a trend for a stronger upper ridge to develop
across the mainland compared to earlier model runs. The forecast
was primarily based on a GFS/ECMWF/UKMET consensus through
Saturday, and then gradually transitioning to about 40-50%
ensemble means by early next week.
...Weather/Hazards Highlights...
A noteworthy warming trend is expected in terms of temperatures
going into next weekend and into Monday/Tuesday as the pattern
over the state becomes more amplified and southwesterly flow aloft
ushers in a warmer air mass by Sunday into Monday. Highs are
expected to reach into the 60s for most inland areas through
Saturday, and then well into the middle to upper 70s across most
of the Interior late in the forecast period, perhaps close to 80
degrees for some of the normally warmer locations. Areas of
moderate to locally heavy rainfall can be expected for western
portions of the Brooks Range late in the week. Terrain enhanced
showers can also be expected for the southern coastal areas, with
the heaviest rain likely for the south facing terrain of the
Alaska Peninsula. Depending on the evolution and proximity of the
incoming Bering Sea low pressure system, breezy to windy
conditions could develop for the western mainland coastal areas.
There may also be enhanced rainfall ahead of this Bering low given
some tropical moisture potentially be advected northward.
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