Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
753 PM EDT Thu Aug 29 2024
Valid 12Z Mon Sep 2 2024 - 12Z Fri Sep 6 2024
...Guidance Evaluation/Preferences...
Models and ensembles show an energetic and progressive flow in a
stormy pattern with average levels of model uncertainty into early
next week. A general blend of best clustered guidance from the
12Z model guidance suite works well as a starting point while
offering some details with the individual shortwaves. There was a
gradual increase to about 60% ensemble means by next Friday as
model spread increases. However, the guidance signal for another
possible impactful Gulf of Alaska storm in about a week has
increased. Uncertainties remain, but the pattern is quite
favorable. Accordingly, WPC applied manual edits to ensure
sufficient low depth in WPC progs given signal and upper trough
support aloft.
...Weather/Hazards Highlights...
An upper level trough with embedded closed low is forecast to
reside over the Gulf region through midweek, and a potential
second low tracking northward into the Gulf by later in the week.
This will tend to keep conditions unsettled for the Southeast
Panhandle where moist onshore flow oriented orthogonal to the
terrain will enhance rainfall, perhaps a few inches of rain for
southern portions of the Panhandle through next Friday.
A potentially stronger storm crossing the Bering Sea by midweek
will likely affect portions of western mainland Alaska by
Wednesday and lasting through Thursday. If the stronger model
solutions come to pass, periods of heavy rain and strong winds
would likely cause some problems for this region, and this would
include the potential for coastal flooding for the Seward
Peninsula and extending south to the Alaska Peninsula. However,
there remains considerable uncertainty in how this event will
evolve, so future adjustments will likely be necessary. In terms
of temperatures, no major temperature anomalies are currently
expected.
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