Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
624 PM EDT Fri Sep 10 2021
Valid 12Z Tue Sep 14 2021 - 12Z Sat Sep 18 2021
...Pattern Overview and Model Guidance...
The strong storm system with the heavy rain and gusty winds is
forecast to abate in intensity by Tuesday over western Alaska.
However, the Aleutians and Gulf region is still expected to have a
rather active weather pattern going through the middle to end of
the week with another strong system tracking from the southern
Bering to the northern Gulf, with perhaps a third system tracking
eastward in its wake.
There is a slight improvement in the 12Z deterministic model
guidance, although some noteworthy timing differences remain
regarding the Bering Sea system by Thursday. The ECENS mean is
initially more progressive and ahead of the CMC/GFS/ECMWF, before
becoming more in line with these solutions by Friday. The
operational ECMWF is still more amplified with the surface low and
upper level features, but not to the same level as yesterday and
still has some ensemble support. The WPC fronts/pressures
forecast is primarily derived from a GFS/CMC/ECMWF/WPC continuity
blend for days 4 through 6, and then more of the GEFS and EC means
for Friday and Saturday.
...Sensible Weather...
Depending on the eventual track and intensity of the next low
crossing the northern Gulf mid-late next week, another episode of
moderate to heavy rainfall is likely from the Alaska Peninsula to
the southeast Panhandle, although confidence in placement of QPF
maxima is limited at this time. Some strong winds are also
possible for portions of the Aleutians and coastal southern
Alaska. Light precipitation is likely across portions of western
Alaska as a frontal boundary approaches the region from the
northwest.
In the temperature department, expect readings to be near to
slightly above normal across much of the Interior, with cooler
weather arriving by the end of next week. Below average
temperatures appear favored for southeastern Alaska and into the
panhandle region.
Hamrick
Hazards:
- Heavy rain across portions of the Alaska Panhandle and mainland
Alaska, Mon, Sep 13.
- High winds across portions of mainland Alaska and the Aleutians,
Mon, Sep 13.
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