Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
756 PM EDT Wed Mar 12 2025
Valid 12Z Sun 16 Mar 2025 - 12Z Thu 20 Mar 2025
...General Overview...
A weakening low pressure system is forecast to reach the British
Columbia coast by Sunday morning. This is followed by another
potentially better organized storm system for early next week that
will cross south of the Aleutians and then over the Gulf by next
Tuesday/Tuesday night. Meanwhile, a strong arctic surface high
will be in place north of the Arctic Coast, with breezy to windy
conditions north of the Brooks Range. A third system is likely to
approach the Aleutians by the middle of next week and then enter
the Gulf by next Thursday.
...Model guidance and predictability assessment...
The 12Z model guidance suite features good overall agreement
across the domain for the upcoming weekend with mainly mesoscale
differences noted. The models also have a reasonably good handle
on the next storm system passing south of the Alaska Peninsula,
with the latest CMC more aligned with the model consensus with
the low compared to previous runs. The arctic surface high north
of the Arctic Coast has good model agreement through the entire
forecast period. For the storm system approaching the Aleutians
late in the forecast period, the ECMWF is still on the slower side
of the guidance, but then falls more in line by next Thursdat once
the low center emerges over the Gulf. The ensemble means were
increased to about half by the middle part of next week.
...Sensible weather and potential hazards...
Most of the mainland should be dry with the exception of some
scattered snow showers across western portions of the Interior,
mainly during the weekend in association with an inverted surface
trough. The next chance of more impactful precipitation would be
next Monday and Tuesday as the second storm system enters the Gulf
and produces an atmospheric river event at the southern mainland
coast and eventually southeast Alaska, with rain near the coast
and heavy snow for the coastal mountain ranges. This is close to
meeting hazards level criteria, but will hold off until tomorrow
to determine if a heavy precipitation area is needed on the
hazards graphic. Windy conditions and some blowing snow are
likely for the North Slope and points north owing to a strong
pressure gradient from the arctic high. No major temperature
extremes are anticipated over the next week.
Hamrick
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