Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
559 PM EDT Mon May 30 2022
Valid 12Z Fri Jun 03 2022 - 12Z Tue Jun 07 2022
...Overview and Weather and Hazard Highlights..
It remains the case that the upcoming early June pattern still
seems fairly quiet for Alaska. An early week warm upper ridge over
the Interior shows some weakness in guidance into later week to
offer lingering chances for scattered showers/convection and local
temperature moderation. This mean ridge separates Arctic upper
troughs/lows to the north of Alaska that periodically force
several fronts through the North Slope and northern Interior from
several closed upper level/surface lows in the North Pacific. In
this flow, a lead/lingering closed low and effects will slowly
weaken well offshore over the southern/southeastern Gulf of Alaska
this period. There is however still some periodic chance for light
to locally moderate precipitation over southern/southeast Alaska
mainly later period with an uncertain series of easterly waves
riding underneath the mean ridge. Meanwhile, a closed upper
trough/low with main/triple point surface lows will slowly
transition from just to the south of the unsettled Aleutians to
well offshore over the western/southwestern Gulf of Alaska as a
moderate maritime threat.
...Guidance/Predictability Assessment...
Latest guidance solutions remain pretty well clustered overall at
larger scales for much of the Alaskan domain and vicinity, but
pesky small-mid scale differences remain. This is mainly evident
into early next week with higher latitude impulses working into
the North Slope and Interior that could act to focus warm season
local showers/convection. A WPC/Alaskan WFO collaborated decision
was to use a composite blend of the best clustered and ensemble
supported 12 UTC GFS/ECMWF/Canadian Friday into the weekend before
transitioning to just the still quite compatible 12 UTC
GEFS/NAEFS/ECMWF ensemble means by next week to provide a
good/consistent forecast basis both over the Mainland and the
North Pacific/Gulf of Alaska where main offshore low solutions
remain well clustered. Manual edits were again applied to offset
the averaging process as needed to best maintain product
continuity in an overall pattern with average to better
predictability.
Schichtel
Hazards:
No significant hazards are expected over Alaska during this
forecast period.
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