Alaska Extended Forecast Discussion
National Weather Service College Park MD
530 PM EDT Mon Jun 9 2025
Valid 12Z Fri 13 Jun 2025 - 12Z Tue 17 Jun 2025
...Guidance Evaluation/Preferences...
The WPC Alaskan medium range pressures, winds, PoPs, and QPF were
mainly derived from a composite blend of moderately well
clustered guidance of the 12 UTC ECMWF/UKMET, lesser weighting on
the 12z GFS/12z Canadian solutions, with increased ensemble mean
contribution from the EC/NAEFS -- this weekend into early next
week -- to help deal with the detail issues that arise in and
near the Bering Sea, south of the Aleutians, and with a system (or
portion of a system) that may retrograde across the far northeast
Pacific/Gulf of AK/coast of southeast and south-central AK. Other
grids were more reliant on the 19z NBM. This solution maintains
reasonable product continuity in an active pattern.
The 12z UKMET/12z ECMWF guidance offers reasonably similar larger
scale flow evolutions into next weekend with persistent ridging
across the AK interior and with a persistent deep layer low near
the southern Bering Sea/Aleutians and a cold low remaining near or
south of the AK Panhandle early on. The least predictable system
in this pattern is the cold low stalling near the AK Panhandle
early on that UKMET/ECMWF guidance has trended southeast with,
again, similar to the good consensus from this past Saturday. The
12z Canadian keeps it in place for a while before retrograding is
west and merging it in with the system near the Aleutians, leaving
another cold low to the west. Differences with the troughing
across eastern Siberia and the Bering Sea leads to a wild 12z GFS
solution that takes the cold low north into southern AK (hence its
minority weighting). It remains to be seen if the guidance has a
good grid on this pattern yet, so confidence appears no better
than average.
...Weather/Hazards Highlights...
Light precipitation and chances of such linger across Southeast
AK and the AK Panhandle. They could fade during the latter half of
Saturday. Rain chances are fairly high across western AK and the
Aleutians as disturbances/low pressure systems move through the
Bering Sea around the eastern side of an isolated cold low.
Periods of gales are expected near the Aleutians and AK Peninsula
through the period with gales also possible near the northwest
coast Wednesday into Thursday; wind gusts are expected to remain
below storm-force. As the flow becomes more east-southeast across
southern mainland AK Friday through the weekend, disturbances in
the flow and associated moisture increases will need to be watched
for thunderstorm potential. Across the eastern interior, NBM
probabilities of 80F+ and 90F+ high temperatures have risen, which
has led to continuation of low to mid 80s being explicitly
forecast late week into next weekend. Probabilities of 90F+ are
over 30% across a small portion of eastern interior AK, resuming
the upward trend noted this past Saturday. Stay tuned.
Roth
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