Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
737 PM EDT Tue Apr 30 2024

Valid 12Z Sat May 04 2024 - 12Z Wed May 08 2024

...Aleutians to Gulf of Alaska Storm Threat through Sunday...


...Guidance Evaluation and Preferences...

Another run of models with above average clustering for mean
trough pattern of through the weekend/start of next week with
above normal predictability. Recently the ECWMF and CMC have been
the front runners for the extended forecast since they have
provided the best detail and evolution and they are complemented
well by the ECMWF/Canadian ensemble means into longer time frames
to offer maximum system and WPC product continuity.

...Weather/Hazards Highlights...

An amplified trough/closed low will continue to track southeast
across the Gulf of Alaska which will favor areas of enhanced
maritime winds/waves and precipitation that should also linger
inland across coastal areas of the southern to southeast tier of
the state to produce some terrain focusing some moderate
precipitation.

During this period portions of the state will have above seasonal
average temperatures for early May, particularly parts of the
southern Interior where anomalies will be the highest. There is
some risk there for enhanced downslope winds off the Alaska Range
into drying soils to monitor for wildfire hazards. Additional
upper troughing over the Arctic Ocean is expected to also settle
down into the northern tier of the state then dig into the Bering
Sea into next week. In this pattern, areas to the north of a
surface front settling over the northern and central mainland in
cold high pressure should keep temperatures below normal,
especially across the unsettled North Slope and northern Interior.
With the unsettled pattern, spotty areas of light precipitation
may be possible.

Guidance continues to highlight development of a much deeper low
pressure system to affect the Aleutians and Bering Sea with
potentially high winds by midweek. This deepened low offers a
potentially hazardous multi-day period with enhanced wind
flow/waves and precipitation set to work downstream. Steady
progression of this well organized/deep storm within the amplified
pattern will lead to enhanced lead inflow to fuel precipitation
into West and Southwest Alaska into Saturday. Ample Gulf of Alaska
redevelopment should offer renewed maritime hazards along with
moderate to heavy multi-day precipitation inland for the Alaska
Peninsula/Kodiak Island and then South-Central to Southeast Alaska
this weekend into early next week.

Upstream, the later period settling of northern stream upper
trough energy into the Bering Sea and subsequent progression of
additional North Pacific system energies may lead to track and
development of another Aleutians organized low pressure/frontal
system to focus winds/waves and rainfall early next week.

Campbell/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