886
FXAK02 KWNH 172323
PMDAK

Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
722 PM EDT Mon Jun 17 2024

Valid 12Z Fri Jun 21 2024 - 12Z Tue Jun 25 2024

...Overview and Guidance Evaluation/Preferences...

Most of mainland Alaska will be situated under a narrow upper
level ridge axis extending from northwestern Canada going into the
end of the week.  A compact upper level polar is forecast to
slowly drift across western Siberia, with gradual weakening going
into next weekend.  Meanwhile, the main storm track across the
North Pacific is expected to feature two low pressure systems,
with the lead system approaching the southeast Panhandle going
into Saturday, and the second one passing south of the Alaska
Peninsula Sunday/Monday, with periods of showers for the coastal
areas, and scattered thundershowers for the Interior.

The 12Z model guidance, along with the 18Z GFS, are in great
overall agreement across the Alaska domain to start the forecast
period Friday, with a general deterministic model blend sufficing
as a good starting point for fronts and pressures, and mainly a
GFS/ECMWF blend for QPF with some previous WPC continuity and
ensemble biased corrected QPF. Going into the weekend, there are
some minor placement differences with the polar low over eastern
Siberia and the weaker upper low/surface low near the central
Aleutians, and the best agreement resides across the eastern Gulf
with the storm system approaching the Southeast Panhandle region.
Model differences grow quite a bit going into next Monday/Tuesday
across the North Pacific, and also across the northern half of the
mainland as a potential second polar low drifts south.  The 18Z
GFS better fits the consensus compared to the 12Z run, which had a
strong low pressure system over the Aleutians/southern Bering
which was not supported by the model consensus nor the ML
guidance.  The ensemble means accounted for about half of the
forecast blend going into early next week.

...Weather/Hazards Highlights...

Isolated to scattered showers/storms can be expected most days
across the Interior during the afternoons and early evenings, with
the best prospects for more widespread coverage on Friday and
again next Monday.  A more organized round of rain is forecast for
the southeast Panhandle going into Saturday, although it`s not
expected to be a major event with most areas getting under an inch
of QPF.  Areas north of the Brooks Range should generally remain
dry with the Arctic high exerting its influence across the North
Slope and Arctic Coast.

In terms of temperatures, afternoon highs are expected to reach
well into the 70s for many areas across the Interior, perhaps
reaching 80 degrees for the Yukon Flats, and also just north of
the Alaska Range.  Overnight lows here should also be rather mild
with readings bottoming out from the upper 40s to upper 50s.  The
Arctic Coast will likely remain chilly with onshore flow from the
Arctic Ocean, with highs generally from the middle 30s to middle
40s.

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

$$