Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
715 PM EDT Fri Aug 09 2024
Valid 12Z Tue Aug 13 2024 - 12Z Sat Aug 17 2024
...Overview and Guidance Evaluation/Preferences...
Upper pattern over Alaska will feature digging troughing into the
Bering Sea, supporting a deepening surface cyclone that will lift
northeastward across the Bering Strait late next week or into next
weekend. The ensembles remain in excellent agreement and formed
much of the blend to the starting point, rounded out by the 00Z
ECMWF, 12Z Canadian, and somewhat the 12Z GFS (to start). Overall,
the GFS/ECMWF were quicker than the ensemble mean consensus
(including the AI/ML ECMWF and EPS) while the Canadian and UKMET
were a bit slower. Given the trend toward a deeper system and more
amplified flow, preferred to stay away from the quickest solutions
and relied heavily on the ensemble means. Over the eastern half of
the mainland into the Panhandle, building ridging along 150W and
troughing into the Panhandle will translate eastward during the
period. Surface high pressure near the Gulf of Alaska will move
eastward in tandem, pushing into Canada next Friday.
...Weather/Hazards Highlights...
The eastern half of the state will be relatively quiet, dominated
by either ridging or drier NW flow in the mid-levels. Lingering
rain over the Panhandle will abate midweek. Over the Bering Sea,
Aleutians, and into the western mainland, the developing system
will bring in increasing chances of rain (modest to perhaps
locally heavier) and windy conditions. Both rainfall and wind may
be just below hazardous levels, so they were left off the hazards
map for now. Still, winds in excess of 40kts are possible in the
warm southerly flow, especially over the water. Rainfall will
maximize in southerly to southwesterly-facing areas of SW Alaska
(Y-K Delta) and into the Seward Peninsula. The system is forecast
to move toward Southcentral by the end of the week.
Maximum temperatures will generally be near to below normal except
for a brief warm-up over the interior as the ridge axis moves
across the mainland. Areas of the North Slope may remain above
normal with offshore flow, downsloping from the Brooks Range.
Minimum temperatures will generally be near to above normal,
especially ahead of the cold front.
Fracasso
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