Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
538 PM EST Mon Jan 11 2021
Valid 12Z Fri Jan 15 2021 - 12Z Tue Jan 19 2021
...Active Weather for Southern Mainland Alaska and Southeast
Alaska...
...Guidance/Uncertainty Assessment...
A persistent trough over the western mainland and eastern
Aleutians is forecast through much of the period while at the
surface a couple strong lows will lift through the Gulf of Alaska.
The first notable storm will be ongoing at the start of day 4 and
is reasonably clustered with the latest guidance across the Gulf
of Alaska. However, the 12Z GFS continued to be an outlier
solution and was largely discounted for day 5 onward. The
ECMWF/CMC idea of a faster flow across the Pacific is preferred
compared to the GFS slower/blocky pattern over the Bering Sea.
With this preference, another area of low pressure is possible
late in the weekend into early next week. The ECENS/NAEFS was used
primarily for day 7/8 which worked well with continuity.
...Weather/Hazards Highlights...
For the period there is expected to be a couple of storm systems
impacting portions of mainland Alaska, the first of which will be
ongoing at the start of the period. Heavy precipitation is
possible and some marine hazards are also possible but are
expected mainly offshore. After a break for day 5/6, another deep
low pressure is forecast to approach the coast and could bring
with it another round of active weather including heavy
precipitation.
Taylor
Hazards:
- Heavy precipitation across portions of the Alaska Panhandle and
mainland Alaska, Thu-Mon, Jan 14-Jan 18.
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