Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
738 PM EDT Sat Apr 02 2022
Valid 12Z Wed Apr 06 2022 - 12Z Sun Apr 10 2022
...Overview...
A general pattern of upper troughing is forecast to persist
through much of next week across western Alaska and the Bering
Sea, with periodic reorienting and reloading and a slight eastward
shift. This should generally keep the storm track south of the
Aleutians, as several pieces of energy attempt to break off from
the trough sending surface lows into the Gulf. Likely the
strongest low should track northeastward toward the Panhandle
Wednesday-Thursday. This pattern will continue to promote a wet
pattern for southern Alaska, particularly over the Panhandle, with
Mainland Alaska remaining mostly dry and cold.
...Guidance/Predictability Assessment...
The latest model guidance continues to show fairly good clustering
with the overall pattern to utilize the deterministic solutions
early with more weighting towards the 12z ECMWF and GFS which
seemed to represent something closest to the ensemble means. After
day 5, a piece of energy may try to break off the base of the
trough forming a closed low over/near southern Alaska. The CMC is
farthest west with this, keeping a closed low lingering over the
Bering Sea due to a much blockier ridge over the western
Aleutians. Meanwhile, the GFS and ECMWF show some sort of weak
troughing breaking through the ridge which acts to push the low
farther into the Gulf, although the ECMWF is notably stronger with
this than the GFS. The ensemble means are expectedly more washed
out than their deterministic counterparts, but generally seem to
support something closer to that of the GFS and ECMWF. Due to
these uncertainties, the WPC forecast leaned increasingly more
towards the ensemble means to help mitigate the differences
somewhat. Used the 12z GEFS/NAEFS as 00z ECENS data was not
available at time of product generation due to local IT issues.
...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 especially for
the Southcentral/Panhandle regions, but the heaviest totals
through the period will be dependent on exact low tracks and
timing. One period of precipitation enhancement could be around
midweek as moist inflow increases ahead of a low headed for the
Panhandle. In fact, the forecast continues to indicate southern
portions of the Panhandle may receive the most precipitation
overall, but as it falls over a several day period, it should not
be too hazardous. Interior Alaska should see generally dry
conditions as the storm track stays to the south, though scattered
snow showers cannot be ruled out. Periods of gusty winds are also
possible over the Gulf and Panhandle with the midweek low pressure
system, and breezy northwest winds may impact the Aleutians late
in the week.
Near to below average high temperatures forecast for Tuesday
across much of the state may ease slightly as the week progresses.
The Brooks Range and the North Slope in particular could be above
normal later in the week for highs, moderating more towards
normal. These colder temperatures may keep river ice breakups on
hold a little later than normal, especially across parts of the
interior. 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