Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
542 PM EDT Sat May 28 2022

Valid 12Z Wed Jun 01 2022 - 12Z Sun Jun 05 2022

...Overview and Weather and Hazard Highlights..

The weather pattern still seems fairly benign for Alaska next week
even though a main/warm upper ridge now shows some weakness in
guidance over the Interior into mid-late week that offers better
chances for local precipitation and some temperature moderation
before reforming later period. This ridge will separate Arctic
upper troughs/lows to the north of Alaska that may periodically
force light precipitation focusing fronts into the North Slope
from several closed upper level/surface lows in the North Pacific.
A fairly strong low will lift into the west-central Gulf of Alaska
into Wednesday, but offers only modest Kodiak Island and maritime
rain/wind threats before slowly weakening over the southern Gulf.
Meanwhile, a closed upper trough/low with moderate main/triple
point surface lows will slowly transition eastward from just to
the south of the unsettled Aleutians to a position well offshore
over the western Gulf of Alaska.

...Guidance/Predictability Assessment...

Guidance solutions still seem pretty well clustered overall at
larger scales for much of the Alaskan domain and vicinity.
However, it now seems more prudent to follow the latest
mid-smaller scale trends of the 12 UTC GFS/ECMWF/Canadian that
have come into better agreement days 4/5 (Wed/Thu) both with the
upper shortwave intrusion from the eastern Bering Sea into the
mainland upper ridge and with the southward track of energies from
the south of the Aleutians to the Gulf of Alaska. This was not the
most likely solution I was expecting yesterday, versus holding
onto the ridge more in particular, but was one of the reasonable
scenarios. The ensemble mean solutions are more compatible by days
6-8 (Fri-next weekend) amid growing forecast spread and
uncertainty and a composite of the GEFS/NAEFS/ECMWF ensemble means
seems a good way to go across the entire domain at these loner
time frames, but did apply targeted manual edits to offset the
blending process to ensure sufficient offshore low depths
consistent with upper support and predictability in an overall
pattern with near average predictability.

Schichtel


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