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FXAK02 KWNH 122340

PMDAK 



Alaska Extended Forecast Discussion

NWS Weather Prediction Center College Park MD

740 PM EDT Sun May 12 2024



Valid 12Z Thu May 16 2024 - 12Z Mon May 20 2024



...Guidance Evaluation and Preferences...



The 12Z model guidance suite is in good agreement on depicting an

amplified trough over the Bering Sea and a downstream upper level

ridge across mainland Alaska for the middle of the week.  Greater

differences exist across the Gulf region with a weakening

trough/surface low, with the 12Z ECMWF depicting a stronger low

over the Gulf that neither the model consensus nor the AIFS

machine learning guidance supports.  Therefore, the preference was

for a CMC/GFS/UKMET/00Z ECMWF blend with more weighting towards

the CMC and GFS through Friday. 



Going into the weekend, the guidance suggests the upper ridge near

the Alaska/Yukon border will slowly break down, while a triple

point low develops near the Alaska Peninsula that drifts into the

northern Gulf region.  The 12Z ECMWF also differs considerably

with a much weaker solution compared to the other deterministic

guidance, so this solution was not favored across this region. 

Therefore, a more ensemble mean based approach was employed for

the fronts/pressures for the Sunday through Monday time period,

while still keeping some of the CMC/GFS.



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



Rain showers will likely be decreasing across southeastern Alaska

on Thursday as a weakening surface low moves inland, and showers

are also likely across western Alaska through Thursday as the

Bering Sea low lifts north towards the Arctic Ocean, along with

some gusty southerly winds.  After that, the next storm system is

expected to arrive Friday across the Alaska Peninsula region and

bring renewed prospects for rain and mountain snow to southern

Alaska.  This then tracks in the general direction of the

southeast Panhandle region by next weekend.  Portions of

south-central Alaska could get 1-3 inches of QPF over the course

of next weekend, but not arising to hazards level criteria.



Temperatures are generally expected to range from the mid 50s to

mid 60s for most Interior locations south of the Brooks Range, and

30s/40s north of the Brooks Range.  Most coastal locations in

southern Alaska should generally be in the mid 40s to lower 50s. 

Lows will generally be in the 30s to mid 40s.





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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