Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
708 PM EDT Tue Jul 04 2023
Valid 12Z Sat Jul 08 2023 - 12Z Wed Jul 12 2023
...Overview and Weather/Hazards highlights...
Alaska weather should stay pretty active during the medium range
period from this weekend into early-mid next week. Lead upper
troughing and unsettled/wet conditions will lift northeastward
across the Interior/North Slope into this weekend and lead to
southern Arctic Ocean low formation. To the west, a next main
system will dive south to the Bering Sea into this weekend,
spinning up a closed upper low and winding surface system set lift
slowly northward over the eastern Bering and western Alaska
through early-mid next week, with eastward motion blocked by
ridging rebuilding over western North America into eastern Alaska.
This will favor possible weekend heavy rain/runoff threat for
Southwest Alaska, with additional activity spreading up through
the western mainland through early-mid next week with slow system
demise.
More uncertainty surrounds additional but less well defined in
guidance possible systems set to work towards the Aleutians and
Bering Sea, with associated surface system and energy/rainfall
focus also then breaking underneath from the North Pacific into
the Gulf of Alaska and into the southern tier of the state next
week.
This general pattern should keep much of Alaska cooler, with
daytime highs 10-20 degrees below normal for this time of the
year. The exception to this will be parts of the eastern Interior
and Southeast Alaska where conditions should stay above normal and
warm (with temperatures into the 70s to near 80 at times).
...Guidance Evaluation/Preferences and Predictabilty Assessment...
Overall, prefer a blend of the reasonably clustered 12 UTC
GFS/ECMWF/UKMET/Canadian Saturday into Monday for best product
continuity and detail consistent with a pattern with near average
predictability. Models continue to exhibit an ongoing trend of
poor forecast spread and run to run continuity by Days 7-8,
lending quick transition to the still compatible ECMWF/NAEFS
ensemble means as uncertainty grows.
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