Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
753 PM EDT Wed Jun 30 2021
Valid 12Z Sun Jul 04 2021 - 12Z Thu Jul 08 2021
...Unsettled weather expected from portions of the Aleutians to
the southern Coast...
...Overview and Guidance/Predictability Evaluation...
During the extended period a deep cyclone near the Bering
Sea/Aleutian Chain will track eastward into the North Pacific/Gulf
of Alaska, which will shift the ridge across eastern Mainland into
Canada. Like the previous cycle, the latest deterministic guidance
and the ensemble means show spread in the location, timing and
strength of individual details, but all in all, the consensus is
decent. There is a trend for a deeper surface low to lift from the
southern Aleutians to the western Gulf/Mainland. The blend for
this issuance comprised of the 12Z UKMET, ECWMF, GFS and CMC
initially before incrementally increasing the weighting of the
ECWMF and GEFS ensemble means.
...Weather/Threats Highlights...
The unsettled weather is expected to shift from the Alaska
Peninsula and Kodiak island into south-central portions of the
mainland before shifting showers and breezy conditions into the
Panhandle region as a low and its attendant fronts move through.
Areas to the north of this eastward trekking system will also see
periods of cloudiness and shower activity. As upper level ridging
is slow to erode across eastern Alaska, especially the first half
of the period, locations across east-central Alaska should be the
warmest with highs in the 70s. Other locations are anticipated to
remain near seasonal normal for early July or be just below
average with the increased cloud cover and upper level troughing.
Campbell
No significant hazards are expected over Alaska during this
forecast period.
Additional 3-7 Day Hazard Information can be found on the WPC
medium range hazards 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