Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
456 PM EST Fri Nov 22 2024

Valid 12Z Tue Nov 26 2024 - 12Z Sat Nov 30 2024

...Guidance Evaluation/Preferences...
Guidance forecast clustering and continuity seems better than
normal into next midweek, bolstering confidence. Prefer a 12 UTC
GFS/ECMWF/UKMET/Canadian model blend Tuesday/Wednesday to preserve
best predictable smaller scale system details, pivoting starting
Thursday to best compatible GEFS/ECMWF ensemble mean blend amid
growing uncertainty and transition. WPC product continuity is good.

...Weather/Hazards Highlights...
A multi-day trend in the guidance still highlights that upper
ridging that has been in place up into the Interior will break
down and retrograde west into the Bering Sea and eastern Siberia
next week, leading to a cooling trend for much of Alaska under
renewed mean upper troughing. As is typical, the coldest readings
will be on the North Slope and eastern interior. In the wake of
system passage, post-frontal gap winds may strengthen/renew near
the AK Panhandle early to mid next week. Guidance spread next week
becomes slowly more significant over time, especially with the
handling of potentially deep offshore storms working from the
Pacific to the south of the Aleutians and then towards the Gulf of
Alaska. This impacts the timing for emergence of a subsequent
downstream deeper moisture inflow/heavy precipitation pattern for
the Southeast, possibly by later next week. The 12 UTC GFS/ECMWF
are much more robust in this development by late next week
compared to the 12 UTC Canadian. Given uncertainties at this time,
a preferred GEFS/ECMWF ensemble mean blend pattern tends to delay
heavier precipitation until late next week, but timing and threat
assessment signals will be monitored over the coming days.

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