Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
325 PM EDT Sat Jul 23 2022
Valid 12Z Wed Jul 27 2022 - 12Z Sun Jul 31 2022
...General Overview...
An anomalous cold upper low will be in place across western Alaska
for early next week along with below average temperatures. This
is forecast to weaken going into the middle to end of the week as
a weak ridge axis tries to build ahead of the next trough across
the Aleutians.
...Guidance/Predictability Assessment...
The 12Z model guidance suite is in good overall agreement going
into the middle of next week, and generally agree on height rises
across the central and southern mainland by the end of the week
ahead of an amplifying trough over the Aleutians. However, the
UKMET and to a lesser degree the CMC, stand out with upper level
troughing persisting a bit longer with a stronger arctic trough
north of the Brooks Range. By later in the forecast period, the
GFS and ECMWF maintain a more well defined trough over the general
vicinity of the Alaska Peninsula, whereas the CMC is oriented
differently and placed farther west with less support from the
ensemble means. Therefore, some deterministic GFS/ECMWF can be
maintained through the entire extended forecast period, whilst
gradually increasing contributions from the ECENS/GEFS.
...Sensible Weather...
Through the middle of next week, a weakening upper-level low and
related surface low pressure system will track eastward, just
north of the Arctic Coast. Temperatures will remain cool through
midweek, with many locations expected to be below normal for late
July. However, readings will begin to moderate/warm across the
southern half of the state as weak ridging moves into the area in
the wake of the first system. Another low is expected to cross
the Aleutians by the middle to end of the week. Overnight lows
are forecast to range from the 30s over the Arctic Coast, to the
40s and low 50s elsewhere. The daily maximums will likely range
from the 50s to 60s south of the Brooks Range, however a few
locations may actually reach the low to perhaps mid 70s.
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