Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
501 PM EDT Thu Nov 03 2022
Valid 12Z Mon Nov 07 2022 - 12Z Fri Nov 11 2022
...Synoptic Scale Overview...
A near-record high pressure system for November will begin the
period across portions of the Yukon before sliding southward and
weakening, causing cold conditions across the AK Panhandle.
Overall, ridging across eastern AK should continue for much of the
period while storminess impacts the southern and western
extremeties of AK.
...Guidance/Predictability Assessment and Preferences...
Overall, the model guidance shows fairly good agreement through
the period, with some spread lingering mid-next week across the
Aleutians with a cyclone moving by to the south early to mid next
week and the persistence of the mid to upper level ridging over
AK. In both cases, weighted against the 12z ECMWF solution,
though a small percentage was included in the blend as a
precaution. A compromise of the 12z GFS, 12z ECMWF, 12z Canadian,
and 12z UKMET sufficed early on before starting to minimize the
ECMWF (and to some degree its ensemble mean) in favor of the 12z
NAEFS for the pressures, 500 hPa heights, and winds. For QPF,
used a compromise of the 19z NBM and 12z GFS, Canadian, and ECMWF
guidance to account for uncertainty. The remainder of the grids
relied heavily on the 19z NBM.
...Sensible Weather and Potential Hazards...
Much of Alaska will begin the week cold and dry in the vicinity of
an Arctic surface high. Strong gap flows continue to be a concern
through early next week
on the back side of low pressure drifting toward the Pacific
Northwest. Over the Southeast Alaska Panhandle, much below average
temperatures are expected through the 9th/early next week as the
frigid Arctic air infiltrates keeping high temperatures
anomalously cold -- in the 20'sF -- for several days in a row.
Otherwise, expect the bulk of the heavy precipitation chances to
be confined to the Northernmost Aleutians and the Kenai through
Tuesday as a triple-point low migrates through the Gulf of Alaska.
Additional high wind and wave concerns remain to the north over
Bristol Bay and into the Bering Sea Sunday/Monday as a pair of
occluding surface lows support strong periods of strong winds
upwards of 60 mph, sometimes favorably oriented toward the coast
to lead to coastal flooding concerns.
Roth/Asherman
- Heavy precipitation across portions of mainland Alaska, Mon-Tue,
Nov 7-Nov 8.
- High winds across portions of the Alaska Panhandle and mainland
Alaska, Sun-Mon, Nov 6-Nov 7.
- High winds across portions of mainland Alaska, Mon, Nov 7.
- Much below normal temperatures across portions of the Alaska
Panhandle, Sun-Wed, Nov 6-Nov 9.
- High significant wave heights for coastal portions of mainland
Alaska, Sun, Nov 6.
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