Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
717 PM EDT Sat Jul 06 2024
Valid 12Z Wed Jul 10 2024 - 12Z Sun Jul 14 2024
...Overview and Guidance Evaluation/Preferences...
Model forecast spread and uncertainty with embedded systems
remains problematic through medium range time scales despite a
still reasonably similar larger scale pattern evolution. Note: The
12 UTC ECMWF was unavailable. Continuity is best maintained with
cycle to cycle consistent and compatible GEFS/ECMWF/Canadian
ensemble means along with WPC manually applied edits to better
depict offshore surface low pressure systems that have favorable
mean upper support.
...Weather/Hazards Highlights...
A slow moving surface front across Mainland Alaska should provide
some focus for local precipitation next week, with higher totals
likely associated with higher terrain given an overall pattern
with favorable upper support. Much of Alaska remains generally wet
and unsettled, which should help bring some relief to wildfire
activity. Also given overall upper troughing over the state into
next week, daytime highs across nearly all of Mainland Alaska will
be well below normal, with the greatest anomalies across western
and northern parts of the state. Temperatures may begin to
moderate into later next week. There is also still some threat to
lift organized low pressure/frontal systems up across the Gulf of
Alaska into next midweek. This track would support unsettled
maritime conditions over the Gulf and offers moderate rainfall
from eastern southern Alaska through the Southeast.
Later period system activity guidance support is less than uniform
in the models, but the preferred ensemble means do still show an
amplified and slowly evolving larger scale pattern with a major
closed upper low/trough centered over the Bering Sea and an
emerging upper trough over the Gulf of Alaska as ample energy
feeds downstream to fuel cyclogenesis and frontogenesis. In this
scenario, heights rise over-top into the eastern Mainland. While
specifics are currently lacking in certainty, this pattern favors
a continued wet and system active period from West/Southwest
Alaska through the southern to Southeast Alaskan tier mid-later
next week into next weekend as unsettling systems will be prone to
develop and evolve/linger over the eastern Bering and downstream
into the Gulf of Alaska to monitor over the coming days for better
clarity. WPC Alaskan medium range surface progs (linked below)
show a well organized mean surface low pressure/frontal system
focus gradually shifting in emphasis from the Bering Sea to the
Gulf of Alaska that portends a multi-day period of moderate
rainfall that adds up over the course of this forecast period.
Schichtel
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