Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
658 PM EST Thu Feb 24 2022
Valid 12Z Mon Feb 28 2022 - 12Z Fri Mar 04 2022
...Overview...
A relatively mild pattern is forecast for Alaska during much of
next week, as southerly flow dominates in between an upper
low/trough across the Kamchatka Peninsula/western Aleutians/Bering
Sea and ridging with an axis over northwestern Canada that should
build over Mainland Alaska by mid next week. A couple of surface
lows should move into the northeast Pacific/Gulf of Alaska while
shortwaves rounding the western trough sends a couple of organized
surface lows across the Aleutians and into the Bering Sea. Above
average temperatures and periods of light to moderate coastal
precipitation are expected with this pattern.
...Guidance/Predictability Assessment...
Recent model and ensemble guidance continues to show good
agreement on the large scale pattern described above, but struggle
with the smaller scale details. There are some timing issues with
surface and weak upper lows over the northern Pacific and Gulf of
Alaska during the early part of next week, but a multi-model
deterministic blend seemed to provide a relatively good starting
point. Meanwhile, a main upper level low will meander near the
Kamchatka Peninsula through much of next week as various
shortwaves rotate across the western/central Aleutians and into
the Bering Sea. The first should reach the Aleutians by around
next Tuesday, weakening by Wednesday over the Bering Sea. The next
system, with model guidance suggesting it should be stronger than
the first, will dross the Aleutians on Thursday as it sends a
frontal system towards the western Mainland and Alaskan Peninsula.
This second system shows some degree of uncertainty in terms of
track and placement of the surface low, but the ensemble means
offer a good middle ground solution. The WPC forecast leaned more
towards the ensemble means for this system given the late period
timing. Some much smaller contributions from the deterministic
solutions were included even through days 7 and 8 for a little bit
of added system definition. This approach maintained good
continuity with yesterdays WPC forecast as well.
...Weather/Hazard Highlights...
Moist southerly flow is forecast to keep rain and snow chances in
the forecast particularly across coastal areas. Precipitation
could be enhanced into early next week with the possibility for a
lingering low pressure system, but with only light to perhaps
locally moderate amounts expected. Precipitation over the southern
Coast and Panhandle should trend lighter with time as upper level
ridging moves into the region. Increasing precipitation and
possibly gusty winds are then forecast for the Aleutians through
much of the workweek, with amounts and timing dependent on low
pressure/frontal systems. Current forecasts show the best signal
for notable precipitation there by around next Wednesday-Thursday.
Above average temperatures will abound over Alaska through much of
next week, especially for lows. The highest anomalies are forecast
over the northern and western parts of the mainland for the
beginning of the week, with lows up to 30-40 degrees above normal
and highs 20-30 degrees above normal. Anomalies will ease with
time, reaching near to slightly below average for highs in the
Panhandle in the southeastern mainland by midweek, but remaining
above normal farther north and west for the week.
Santorelli
No significant hazards are expected over Alaska during this
forecast period.
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