Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
618 PM EDT Tue Apr 15 2025
Valid 12Z Sat 19 Apr 2025 - 12Z Wed 23 Apr 2025
...Guidance/Predictability Assessment...
Prefer a composite solution of best clustered guidance from the 12
UTC GFS/ECMWF/Canadian models as valid for the weekend. This
solution has good ensemble support and continuity in a pattern
with seemingly above normal predictabililty. Opted a switch to a
blend compatible guidance from the 12 UTC GEFS/ECMWF/Canadian
ensemble means as valid for next week in a period with growing
forecast spread. Manual adjustments were applied at WPC to show
sufficient offshore low pressure system and wrapping wind
strengths given likely support and to mitigate weakening by the
blending process. WPC product continuity was reasonable.
...Weather/Hazards Highlights...
Scattered rain and snow showers should continue across parts of the
Mainland into the weekend with mean upper level troughing in
place. The next organized storm system develops over the
central/western Aleutians over the weekend and will likely track
in the general direction of the southeast Bering Sea into early
next week, bringing wrapping rain/snow and gusty winds. Ahead of
this system, expect a building ridge axis from the Gulf to the
Interior. This ridge breaks down by Tuesday as system energies
regroup over the Gulf of Alaska with triple point low/frontal
genesis that lingers/slowly propagate next midweek to moderately
affect maritme interests and coastal southern to southeast AK.
There is more uncertainty by these longer time frames, but another
organized low in the series may also approach the Aleutians.
In this scenario, moisture will work in particular to favored
terrain of the Alaska Peninsula, Kodiak Island and the Kenai
Peninsula by early next week and then Southeast Alaska with slow
system translation. This does not appear to meet hazardous level
criteria at this time. Temperatures are expected to be near to
above average across central and western portions of the state,
and below average across the northeastern mainland where the
Arctic high will have more of an influence on the weather.
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