Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
501 PM EST Wed Jan 31 2024
Valid 12Z Sun Feb 04 2024 - 12Z Thu Feb 08 2024
...Bitterly cold temperature focus to linger over the eastern
Interior this weekend...
...Overview...
It remains the case thta deep upper troughing and embedded closed
low over Alaska should shift east into northwest Canada by the
weekend as upper ridging builds in upstream and shifts over the
Mainland. This should help moderate bitterly cold temperatures
across the state as well as usher in a drier overall pattern for
much of the Interior. A deep upper low will affect much of the
Aleutians into the weekend with increased precipitation and gusty
winds before rotating north/westward and becoming absorbed into an
additional upper low dropping down from the Kamchatka Peninsula.
Multiple streams of energy rotating around the base of this broad
trough will keep conditions quite unsettled across the Aleutians
and more moderately from Southwest Alaska through the Alaska
Peninsula and downstream into the southern to Southeast Alaskan
coastal tier.
...Guidance Evaluation/Preferences...
12 UTC GFS/ECMWF/UKMET/Canadian solutions seem reasonably
clustered for Sunday/Monday at medium to larger scales. A favored
composite tends to mitigate individual system variances consistent
with uncertainty. This strategy maintains good WPC product
continuity for this period in a pattern with near average overall
predictability. Prefer to gravitate to still compatible GEFS/ECMWF
ensemble means into longer time frames Tuesday-next Thursday amid
growing forecast spread and run to run continuity issues.
...Weather/Hazards Highlights...
A deep surface low near the Aleutians into Saturday should support
increasing precipitation from west to east as the cold front
shifts through the Aleutians. There is also likely to be a period
of gusty high winds given the strong pressure gradient present.
Additional surface lows into early next week will continue to keep
unsettled conditions across the Aleutians and farther east towards
Southwestern Alaska and AKpen with wrapping flow, then downstream
for the southern to Southeast Alaska. This will be fueled by
general moist southerly flow as system energies/triple point lows
split underneath the state into the northern Gulf of Alaska, with
periodic activity with weakened systems working across the Gulf of
Alaska toward the Southeast.
Well below normal temperatures lingering into the weekend may
still include some locally colder than -50F values over colder
spots of the eastern Interior, but there should be an overall
easing of the current Mainland frigid pattern as mean upper
ridging builds over the state. By next Monday-Tuesday, the
greatest positive anomalies should be across western Alaska and
the North Slope along with parts of Southwest Alaska, where
daytime highs could be 10-20+ degrees above normal, a strong
contrast to conditions currently. Southeast Alaska looks to stay
near or below normal most of the forecast period.
Schichtel
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