Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
624 PM EDT Sat Sep 11 2021
Valid 12Z Wed Sep 15 2021 - 12Z Sun Sep 19 2021
...Pattern Overview and Model Guidance...
The strong storm system with the heavy rain and gusty winds during
the short range forecast period 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. A
third system is likely to be tracking eastward in its wake,
although the intensity is expected to be weaker.
Some noteworthy timing differences remain regarding the Bering Sea
system for the middle of the week. The GFS is slower than the
model consensus with the low and is not favored for Wednesday and
Thursday, but it is more in line with the other guidance later in
the forecast period with this feature. The ECMWF and its mean are
faster, with the UKMET serving as a good middle ground solution.
By the end of the forecast period, the CMC becomes out of phase
across the Gulf region and loses ensemble support, so it was not
incorporated for next weekend.
...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 next weekend as the cold front settles
southward from the Arctic. Below average temperatures appear
favored for southeastern Alaska and into the panhandle region with
increased cloud cover and frequent showers..
Hamrick
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