Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
729 PM EDT Fri Jun 28 2024

Valid 12Z Tue Jul 02 2024 - 12Z Sat Jul 06 2024

...Overview and Guidance Evaluation/Preferences...

The ensemble means from the GEFS, EC, and CMC continue to provide
good to excellent agreement on the evolution of the upper-air
pattern across Alaska through the medium-range period.  The Rex
Block upper-air pattern setting up in the vicinity of Alaska
during the short-range period will persist into much of the
medium-range period.  Models continue to depict an initially deep
Bering Sea low will weaken as it slides to the south of an upper
ridge that will be anchored across northern Alaska. The WPC
medium-range grids for Alaska maintained continuity by utilizing a
40% GFS/GEFS mean, 40% ECWMF/EC Ensemble mean and 20% CMC/CMC mean
weighting through the entire extended period.

...Weather/Hazards Highlights...

A rainy pattern will linger across portions of the Aleutians and
Alaska Peninsula initially as the Bering Sea cyclone gradually
slides across these areas before drifting farther to the east or
southeast early next week. The terrain in south-central and
northern Alaska are expected to have the best chance of showers
and thunderstorms nearly each day and with the convection comes
the possibility of dry lightning strikes during the afternoons and
evenings. This would increase the risk for fire weather concerns
given the dry fuels across the region.

Ridging across mainland Alaska will maintain warm to hot
temperatures. Daily highs are expected to rise into the 80 to 90F
range for the most part across the eastern interior sections with
mostly 60s and 70s expected across lower elevations of
south-central Alaska, 50s and 60s in most coastal areas, 50s and
40s across the North Slope, and mid to upper 40s in the Aleutians.
 Higher elevations in the terrain across south-central and
southeast Alaska should fall below freezing overnight.  The North
Slope will cool down closer to normal temperatures by Sunday as a
surface high pressure system gradually sliding from west to east
off the northern coastline of Alaska funnels colder air into the
area from the Arctic Ocean.  Similar temperatures are expected to
last into late next week across mainland Alaska but with a gradual
expansion of the coverage of scattered showers and embedded
thunderstorms when upper shortwave energy from the Arctic Ocean
could penetrate the upper ridge and destabilize the atmosphere.

Campbell


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