Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
644 PM EDT Thu Aug 06 2020
Valid 12Z Mon Aug 10 2020 - 12Z Fri Aug 14 2020
...Guidance Evaluation and Preferences...
Troughing over the mainland will be reinforced from the west as a
defined Bering system straddles the Aleutians next week. The 12Z
models and ensembles offered a reasonable clustering for most of
the features through next Wed, and a consensus blend was suitable.
This did nudge the Bering system a bit farther south, passing
along the Aleutians rather than through the southern Bering.
Thereafter, models/ensemble means were split in how the system
evolves into the Gulf. There may be enough downstream riding,
albeit weak, to help temporarily slow the Aleutian system before
the ridge erodes and the system continues westward, but this was
not shown by the 12Z GFS/ECMWF/Canadian. Favored that cluster with
only a minority ensemble weighting (which was split/sheared in
appearance fast vs slow) which showed the system progressive and
eventually into the Gulf later next week.
...Weather Highlights/Threats...
Bering/Aleutian system next week Mon-Thu will bring showers/rain
to the Aleutians with breezy conditions as well as the modest
parent low scrapes the islands. Expect light to modest rainfall
into western/southwestern areas as the warm front approaches early
Wed. This will spread eastward across Southcentral as the triple
point develops in the Gulf, perhaps enhanced by next Thu/Fri as
the upper trough head eastward. Temperatures will be within
several degrees of normal through the period, trending just a bit
milder overall.
Fracasso
Additional 3-7 Day Hazard information can be found on the WPC
medium range hazards chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php
Hazards:
No significant hazards are expected over Alaska during this
forecast period.
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