Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
654 PM EDT Thu Mar 31 2022
Valid 12Z Mon Apr 04 2022 - 12Z Fri Apr 08 2022
...Overview...
A general pattern of upper troughing should persist through much
of the period, especially for western Alaska and the Bering Sea.
At this surface, this keeps the storms track generally south with
systems moving through the north Pacific/Gulf of Alaska, while
additional low pressure may linger near the southwestern Mainland
into the middle of next week. This will promote a wet pattern for
southern Alaska, particularly over the Panhandle, though amounts
do not look to be terribly heavy.
...Guidance/Predictability Assessment...
The latest model guidance continues to show fairly good clustering
with the pattern during the first half of next week, featuring an
upper low near the Panhandle on Monday and an elongated upper low
over the western Mainland which should drift slowly westward into
the middle of the week. Several systems will round the base of
this trough with developing low pressure lifting towards the
Panhandle mid week and another across the Bering Sea/Peninsula and
eventually into the Gulf by the end of the period. Farther
upstream, recent GFS runs continue to show a second surface low
across the western Bering which crosses the Aleutians around day
5-6, but other pieces of guidance don't provide much support for
that. Otherwise, most of the uncertainty late period is from
typical timing and strength of individual low pressure systems. By
day 7, the 12z ECMWF is a little bit weaker and faster to send the
Panhandle low into western Canada, while the CMC/GFS maintain
circulation off the coast.
The WPC preference featured a purely deterministic model blend
(with slightly more weighting towards the 12z ECMWF) for days 4-5.
After that, the blend leans increasingly more on the ensemble
means to help mitigate the late period differences mentioned
above. This resulted in reasonably good continuity with yesterdays
WPC forecast over Alaska, as well as today's forecast farther
downstream across the CONUS.
...Weather/Hazard Highlights...
Precipitation is possible over southern parts of Alaska from the
Aleutians and Alaska Peninsula east into Southcentral Alaska and
the Panhandle through much of next week near low pressure systems.
Some rain/snow amounts could be enhanced at times, but the
heaviest totals through the period will be dependent on exact low
tracks that remain uncertain at this point. The current forecast
indicates southern portions of the Panhandle may receive the most
precipitation overall, but as it falls over a several day period,
it shouldn't be particularly impactful. Interior Alaska should see
generally dry conditions as the storm track stays to the south.
Periods of gusty winds are also possible along low tracks, and the
gradient south of Arctic high pressure may support a period of
breezy conditions across the North Slope and cold wind chill
values.
Near average to below average highs are forecast over much of the
state early in the week, with the greatest anomalies across the
North Slope and lower elevations of the interior. The cold
anomalies could ease by the middle of next week, with some
locations across northern Alaska above normal. Low temperatures
should be closer to normal over the North Slope and Interior
compared to the cool highs, while milder than average lows are
predicted in the southern mainland and the Brooks Range. The
Panhandle can expect to see below normal highs and around average
lows through the period owing to mostly cloudy skies and wet
conditions.
Santorelli
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