Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
618 PM EDT Thu Aug 04 2022
Valid 12Z Mon Aug 08 2022 - 12Z Fri Aug 12 2022
...Cold and wet pattern setting up over much of Alaska, especially
the North Slope/Interior, with rounds of heavy rainfall possible
across the South/Southeast...
...Overview...
A deep closed low will drive a cold front across western/central
Alaska and into the Gulf, with precipitation including mountain
snows become increaisngly likely across the Mainland. This system
will usher in a much cooler regime across Alaska lasting into at
least the middle of next week. Meanwhile, yet another chance for
heavy rainfall develops into southern/southeast Alaska next week.
...Guidance/Predictability Assessment...
The 12 UTC GFS/ECMWF look pretty reasonable and consistent into
Monday/Tuesday, but opted to transition to the still compatible
GEFS/ECMWF ensemble means by next Thursday/Friday amid growing
forecast spread. Forecast predictability slowly lowers from above
normal to near normal values during this period. The latets models
show moderation of the mainland cold snap later next week, but
that scenario will be monitorred as the lead-in pattern shows
ample digging of northern stream/Arctic energies that may prove
slow to relinquish. Overall, WPC product continuity was decently
maintained in this active and unsettled weather pattern.
...Sensible Weather...
Much of mainland Alaska looks to remain rather unsettled next week
as strong systems dig into region. This likely brings protracted
periods with gusty winds as well as widespread precipitation. Some
of this precipitation could fall as snow, particularly parts of
northwest Alaska and elevated terrain. The heaviest precipitation
should shift south and east with time next week, with the
potential for heavy rainfall once again returning to parts of
south/southeast Alaska and the Panhandle region as low pressure
systems focus a plume of long fetch Pacific moisture across the
region. For the most part, precipitation over the Aleutians/Alaska
Peninsula region will be more limited, with more organized
activity to approach later next week as a system slides to the
south across the northern Pacific.
Chilly temperatures will overspread much of Alaska, including the
Panhandle by this weekend with daytime highs as much as 10 to 20
degrees below normal. The highest anomalies will feature across
the North Slope region though, where anomalies could be as high as
30+ degrees below normal and morning low near or below freezing
for some places. Temperatures may begin to moderate from west to
east mid-later next week.
Schichtel
Hazards:
- Heavy rain across portions of the Alaska Panhandle and mainland
Alaska, Mon-Wed, Aug 8-Aug 10.
- Much below normal temperatures across portions of mainland
Alaska, Sun-Thu, Aug 7-Aug 11.
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