999
FXAK02 KWNH 202352
PMDAK

Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
751 PM EDT Thu Jun 20 2024

Valid 12Z Mon Jun 24 2024 - 12Z Fri Jun 28 2024

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

Just prior to the extended period a surface low/upper low will be
tracking toward the south of Panhandle this weekend. There will be
three main low pressure systems that will be the focus thereafter.
A slowly retrograding polar upper low is expected to move across
eastern Siberia, a system tracking south of the Aleutians and
although still fuzzy on the details, a third system that
approaches the western Aleutians by middle of next week.
Meanwhile, most of mainland Alaska will be between these Pacific
storm systems and an arctic upper trough north of the state, with
pleasant early summer weather expected south of the Brooks Range.

The guidance is handling the large scale pattern fairly well
initially and then fair for the later periods which a typical
degree of spread and uncertainty. The continued approach of using
a multi-model consensus for a starting point has proved
beneficial. The start of this coming week used a combination of
the ECWMF, GFS, CMC and UKMET before dropping the UKMET, reducing
inclusion of the CMC while adding in the ECWMF and GEFS ensemble
means for the later period. As previously noted, the spread in
guidance increases a fair amount for the last couple of days of
the extended which lowers confidence on the exact track of the
last system near the Aleutians.

...Weather/Hazards Highlights...

This active pattern will keep shower activity possible for the
Brooks Range and much of the southern tier of the state. Showers
and thunderstorms are expected to produce light to moderate
amounts across the Interior and surrounding areas. For the
Interior, the possibility for thunderstorms and dry lightning
strikes during the afternoons and evenings may increase the risk
for fire weather concerns given the dry fuels across the region.
Areas north of the Brooks Range will likely remain dry through the
week. Some showers are also likely across the central and eastern
Aleutians as the next low pressure system passes by to the south
and again later in the period.

Weak ridging across the Mainland will lead to near normal or
slightly warmer than normal temperatures. Afternoon maximums are
expected to climb 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
upper 30s to upper 40s.

Campbell


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

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