Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
745 PM EDT Fri May 17 2024

Valid 12Z Tue May 21 2024 - 12Z Sat May 25 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 beginning
of next week, with mainly mesoscale differences noted with the
Bering Sea low and developing triple point low near the Alaska
Peninsula.  The UKMET differed the most from the consensus with a
farther east solution with the Bering Sea low on Tuesday, and even
more so with the next low arriving behind it.  Going into
Thursday, the CMC becomes a slower solution with the second Bering
Sea low compared to the ensemble means, and the GFS is a weaker
solution.  By the end of the forecast period next Saturday, there
is a general signal for a Gulf low developing among the
deterministic guidance, but greater differences across the Arctic
where the ECMWF indicates more of a surface high whereas the GFS
depicts a surface trough. 

The WPC fronts/pressures forecast was primarily derived from a
GFS/ECMWF/CMC compromise with a little UKMET on Tuesday, followed
by gradually increasing percentages of the ECENS and GEFS through
the end of the week to about 50% by next Saturday, 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 on Tuesday
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 Saturday, 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.  Temperatures are forecast to be rather
pleasant for most Interior locations, with highs generally in the
60s 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