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FXAK02 KWNH 102337

PMDAK 



Alaska Extended Forecast Discussion

NWS Weather Prediction Center College Park MD

736 PM EDT Fri May 10 2024



Valid 12Z Tue May 14 2024 - 12Z Sat May 18 2024



...Guidance Evaluation and Preferences...



Model guidance continues to indicate broad troughing over Mainland

Alaska for the beginning of next week, with shortwave energy

across the Alaska Peninsula and extending southwest over the

northern Pacific creating a positively tilted trough. This trough

and the associated surface low is forecast to track northeast

toward the Gulf by midweek and gradually weaken, although some

timing uncertainty remains in the guidance.  The strength of the

surface low varies a bit as well but recent models do not show it

to be all that strong.



Farther west, models continue to advertise the next round of upper

level shortwave energy tracking from Siberia across the Kamchatka

Peninsula and leading to the development of a closed low over the

Bering Sea.  While Tuesday-Wednesday has become more agreeable for

the timing of this system to move into the Bering Sea region,

model differences become more significant going into the end of

the week.  Of particular note is a much more amplified GFS

solution with a triple point low that develops near the Aleutians,

and becomes an outlier solution for the second half of the

forecast period.  A mainly deterministic model blend sufficed as a

starting point in the forecast process for Tuesday with a little

more weighting to the ECMWF, and then dropping the GFS by Thursday

and beyond.  The proportion of the GEFS and EC ensemble means

increased to about 60% by Day 8 amid the increasing uncertainty. 

This seemed to provide a reasonable middle ground, although

changes are very likely in the days ahead as the guidance comes

into better focus.





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



For the Tuesday-Wednesday time period, a surface low reaching the

northern Gulf should bring additional rain and mountain snow to

much of south-central Alaska.  It appears precipitation amounts

will likely be on the moderate side, with some locally heavier

totals possible but not significant enough to warrant any areas on

the WPC hazards outlook.  Some lighter precipitation in the form

of rain showers and higher elevation snow showers should extend

into the Interior as well. Then there is considerable uncertainty

regarding rain/mountain snow and winds that may affect the western

Mainland and/or Aleutians by midweek and beyond depending on how

the pattern evolves. Low confidence in the sensible weather

persists into the latter part of next week and into next Saturday,

but generally some light to moderate precipitation seems possible

for the southern coast.

In terms of temperatures, highs should generally be in the 50s and

60s for most inland locations, and lows from the mid 30s to mid

40s.  The Arctic Coast will continue to remain colder as highs

slowly break the freezing mark.



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



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