Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
718 PM EDT Thu May 25 2023
Valid 12Z Mon May 29 2023 - 12Z Fri Jun 2 2023
...Synoptic Overview...
A closed upper low over the northern Gulf of Alaska is forecast to
slowly track east towards the southeast Panhandle through the
middle of next week, with a reinforcing shortwave dropping south
behind it. Upper level ridging builds in across the Aleutians and
the Bering for the Wednesday to Friday time period between the
Gulf low and another storm system emerging off the Kamchatka
Peninsula. Meanwhile, a polar cold front is forecast to drop
south from the Arctic and bring colder weather for the Brooks
Range and points north by midweek.
...Guidance Evaluation/Preferences...
The 12Z model guidance suite is in good overall agreement on the
synoptic scale features through next week, with generally above
average confidence noted for a day 7 and 8 forecast for most
areas. The 12Z CMC was slightly misaligned with the consensus for
Monday and Tuesday, but it was reasonably close to the ensemble
means going into Wednesday and beyond. Therefore, a
UKMET/GFS/ECMWF blend worked as a starting point through Tuesday,
and then the CMC was substituted for the UKMET starting Wednesday
whilst increasing use of the ensemble means to about 40 % by the
end of the week, and still keeping about 20% each of the
CMC/GFS/ECMWF.
...Sensible Weather and Potential Hazards...
Much of the Southeast and southern coast will likely have ongoing
light to occasionally moderate showers, owing to the slow moving
disturbance over the northern Gulf. However, no areas of
significant rainfall or snow are currently expected for this time
period. Isolated to scattered showers will be possible across
portions of the Interior that will mainly be diurnally driven.
For the first half of next week, most of the central and southern
portions of the state will likely have slightly below average high
temperatures, and above average for the northern third of the
state ahead of the polar front. Cooler conditions return to the
North Slope and Arctic Coast behind the front later in the week,
and generally within 5-10 degrees of average elsewhere across the
state with no temperature extremes expected. This will mainly
equate to highs 55 to 65 and lows 35 to 45 for most locations.
Hamrick
No significant hazards are expected over Alaska during this
forecast period.
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