Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
747 PM EDT Sat May 27 2023
Valid 12Z Wed May 31 2023 - 12Z Sun Jun 4 2023
...Synoptic Overview...
A shortwave dropping south across the Alaska Peninsula will help
to re-establish the closed low again over the Gulf going into the
middle-end of the week. Upper level ridging briefly builds in
across the Aleutians and the Bering for the Wednesday to Friday
time period ahead of the next low pressure system approaching from
the general direction of the Kamchatka Peninsula, with a closed
low likely over the southern Bering by next weekend. Meanwhile, a
warm front will likely lift north through the entire state by next
weekend and bring some of the warmest weather of the season thus
far.
...Guidance Evaluation/Preferences...
The 12Z model guidance suite is in good overall agreement on the
main synoptic scale features through next week. Some placement
differences become apparent with the 12Z GFS and GEFS mean across
the Gulf as the second shortwave builds southward, and it is
displaced to the southwest of the CMC/ECMWF by Thursday and
beyond, but generally more agreeable across mainland Alaska and
handles the next storm over the Bering/Aleutians well. The CMC is
southeast of the model consensus with the Bering low next weekend,
but is similar to the consensus across the mainland. The
fronts/pressures incorporated a general deterministic blend
through Thursday, followed by slightly less of the GFS/CMC by next
weekend whilst increasing contributions from the ensemble means to
about half by that time.
...Sensible Weather and Potential Hazards...
Much of the Southeast and southern coast will likely have ongoing
light to occasionally moderate showers through Friday, owing to
the slow moving disturbances 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. A more concentrated band of showers may develop across
the Aleutians later in the period as the next storm system
approaches. Temperatures will generally be slightly cooler than
average for most days across much of the mainland for the
Wednesday to Thursday time period, with the greatest anomalies
expected across western Interior areas. However, a noteworthy
warming trend is likely to commence Friday and especially into
next weekend as a warm front lifts northward with upper level
ridging in place. Afternoon highs could make a run at 80 degrees
for some of the lower elevations in the Interior, and widespread
70s elsewhere.
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