Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
330 PM EDT Wed Aug 28 2019
Valid 12Z Sun Sep 01 2019 - 12Z Thu Sep 05 2019
...Deep low will lift to the eastern Bering Sea to threaten Alaska
this weekend into early next week...
The latest models and ensembles strongly agree that a potent low
pressure system with surface pressures as deep as the 970 mb range
in the models will lift from the Aleutians through the eastern
Bering Sea Sunday through early next week as upper ridging over
the eastern mainland slips eastward into Canada. A blend of the
quite well clustered and reasonable 12 UTC GFS and ECMWF was used
in this period of above average forecast confidence. This system
will be a hazard for maritime interests and a downstream heavy
weather/precipitation threat to focus into western/southwestern
Alaska and acrossn the southern Alaska tier over time considering
moisture transport and dynamic support aloft. Forecast spread
increases by day 7/8, suggesting usage of just the more compatable
ensemble means at these longer and less certain time frames. Upper
trough amplification by then into the western Bering Sea/Aleutians
may support a pattern favorable for another deepening low system.
Schichtel
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
- Heavy rain across portions of mainland Alaska and the Aleutians,
Sat-Mon, Aug 31-Sep 2.
- High winds across portions of mainland Alaska and the Aleutians,
Sat-Sun, Aug 31-Sep 1.
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