Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
749 PM EDT Sat May 18 2024

Valid 12Z Wed May 22 2024 - 12Z Sun May 26 2024

...Guidance Evaluation and Preferences...

The 12Z model guidance suite has a good overall depiction of the
synoptic scale pattern across the Alaska domain for the middle of
next week, with mainly mesoscale differences noted with the Bering
Sea low and developing triple point low over the northern Gulf. 
The UKMET was more in line with the consensus compared to its
faster solution from yesterday.  Going into Friday, the CMC
becomes a slower solution with the second Bering Sea low compared
to the ensemble means, but still close enough to be a part of the
model blend.  By next weekend, there is a general signal for a
Gulf low developing among the deterministic guidance, and another
trough approaching the western Aleutians by Sunday.  

The WPC fronts/pressures forecast was primarily derived from a
multi-deterministic model compromise for Wednesday and Thursday,
followed by gradually increasing percentages of the ECENS and GEFS
going into next weekend, while still maintaining the GFS/ECMWF and
a little of the CMC. 

...Overview and Weather/Hazards Highlights...

The developing triple point low over the northern Gulf midweek is
expected to result in generally unsettled conditions with mainly
nuisance level precipitation owing to moist onshore flow, but
below hazardous level criteria for the southern coastal areas. 
The heaviest QPF is expected for the southern Kenai Peninsula to
the Prince William Sound region through Wednesday, followed by a
drier weather pattern through Friday before rain/snow chances
increase once again for next weekend, depending on how the next
Gulf low evolves. Elsewhere across the state, periods of light to
occasionally moderate rain can be expected across western mainland
Alaska as southerly flow advects moisture northward ahead of the
Bering Sea low through midweek, although most of the North Slope
should remain mostly dry and colder.  Temperatures are forecast to
be rather pleasant for most Interior locations, with highs
generally in the 60s to perhaps 70 degrees for the lower
elevations, and lows from the upper 30s to middle 40s.  Readings
closer to the southern coast will generally be in the upper 40s to
middle 50s, and in the 30s for the Arctic Coast.

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