Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
458 PM EDT Fri Jul 12 2024
Valid 12Z Tue Jul 16 2024 - 12Z Sat Jul 20 2024
...Wet pattern the Alaska Panhandle next week...
...Overview and Guidance Evaluation/Preferences...
The guidance agrees that a strengthening polar vortex along with a
deep layer cyclone moving from eastern Asia into the Bering Sea
will escort a cold low from southwest AK into the Gulf of AK and
the adjacent northeast Pacific. The guidance shows broad
agreement on these ideas. Details remain an issue, so have relied
upon a deterministic blend of the 12z runs of the ECMWF, UKMET,
Canadian, and GFS early on before using increasing amounts of the
12z NAEFS/00z ECMWF ensemble mean solutions thereafter. For the
pressures/fronts, this maintained reasonable continuity. The QPF
is more weighted towards a non-ECMWF deterministic blend, while
many of the weather grids used the 19z NBM as a starting point.
...Weather/Hazards Highlights...
The southern portions of Alaska will be unsettled, with the
wettest conditions expected across the AK Panhandle next week.
Another cyclone on its heels should keep the Aleutians unsettled
with a distinct chance of gale force winds. Cumulative heavy rain,
2-4" areal average amounts and local amounts of 6" are possible in
the Panhandle. The heavy rain threat will generally decrease by
midweek as the cyclone weakens but the rain can be expected to
linger through late week with a period of enhanced rainfall
possible in the Panhandle with the arrival of a low pressure wave,
which the guidance isn't especially agreeable on, timing-wise.
The remainder of the state will remain unsettled with scattered
showers and perhaps some embedded thunderstorms. High
temperatures will be more evenly distributed, with 60s and 70s in
the central Valley, 40s and 50s on the North Slope, and 50s and
60s elsewhere. Subfreezing lows should be constrained to the
higher terrain of the Brooks Range and the various ranges across
south-central and southeast Alaska.
Roth/Kong
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