Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
744 PM EDT Tue Jun 22 2021
Valid 12Z Sat Jun 26 2021 - 12Z Wed Jun 30 2021
...Rainy conditions expected for portions of the Aleutians,
Alaskan Peninsula, Kenai Peninsula, and the panhandle later this
The latest guidance and the ensemble means persist in keeping a
mean trough over the Aleutian Chain and portions of Southwest
Alaska with multiple surface lows moving through. The strength and
timing of each cyclonic circulation varied by each model
depiction; however the solutions are fairly clustered over the
Bering Sea, Aleutians and western Gulf of Alaska through about 12Z
27th. The clustering decreases though the 28th before becoming
quite spread out by 12Z 29th.
The WPC Alaskan medium range product suite was a composite blend
of 12Z GFS/ECWMF/CMC/UKMET initially with increasing weights of
the 12Z GEFS mean/00Z EC mean from mid to late in the extended
period. This blend maintains the deeper cyclone before gradually
weakening it and moving towards the Bering Sea.
This storm is still expected to support locally heavy rain from
the Kenai peninsula over to southeast AK/panhandle, as well as,
increased cloudiness and rain near the North Slope. The potential
for rain will linger into the weekend before this boundary weakens.
A new cyclone is expected to develop at the base of the Bering Sea
trough in the north Pacific, impacting the adjacent Aleutians, up
to and including the AK peninsula next Monday, bringing another
round of wind and showers to these regions. Also during the course
of the extended period, temperatures are forecast to be above
seasonal average-- especially across the Panhandle as the ridge
over the north Pacific Ocean persists. Elsewhere, temperatures
will largely be near normal or slightly cooler than average.
- Heavy rain across portions of the Alaska Panhandle and mainland
Alaska, Fri, Jun 25.
WPC medium range Alaskan products including 500mb, surface
fronts/pressures progs and sensible weather grids can also be