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FXAK02 KWNH 132356

PMDAK 



Alaska Extended Forecast Discussion

NWS Weather Prediction Center College Park MD

755 PM EDT Sat Apr 13 2024



Valid 12Z Wed Apr 17 2024 - 12Z Sun Apr 21 2024



...Synoptic Overview, Guidance Evaluation, & Preferences...



An upper level ridge axis is expected to be in place across the

eastern mainland and into the Yukon Territory and southeast

panhandle region for the middle of the week.  Meanwhile, a storm

system over the North Pacific tracks in the general direction of

the AK Peninsula by late Wednesday before stalling, and then

slowly moving back to the south over the central Gulf.  This

brings a return to more rain and snow for southern coastal areas

of the state, particularly from the AK Peninsula to Kodiak Island.

 Meanwhile, a second low pressure system is forecast to track

across the Bering and weaken with time through midweek, and some

of the shortwave energy from this may interact with the low moving

north across the western Gulf. 



The 12Z model guidance suite features decent overall synoptic

scale agreement across the Alaska domain for the beginning of the

forecast period Wednesday.  Upon examination of the ML guidance

from the ECMWF, there is more support for the faster northward

track of the low towards Kodiak Island by 12Z Wednesday, which is

also closer to the 12Z GFS position.  The CMC depicts a solution

with the low south of the model consensus over the Gulf, but an

overall improvement compared to recent days.  The fronts/pressures

forecast was based on a multi-model blend as a starting point

through Thursday with more weighting towards the GFS given its

solution more in line with the ML guidance, and then increasing

percentages of the GEFS and EC means going into next weekend.





...Weather/Hazards Highlights...



Coastal rain and mountain snow is likely to increase going into

the Wednesday-Thursday time period from Kodiak Island to the

Prince William Sound region as moist onshore flow increases ahead

of the Pacific low moving towards the coast.  Similar to

yesterday, there has been a slight westward trend with the highest

QPF from this event, with the highest totals near Kodiak Island

and the eastern AK Peninsula.  Strong onshore flow over this

region is expected to produce high waves and gusty winds over 40

mph at times, especially through coastal inlets.  Light showers

are possible farther inland across southern mainland Alaska. 

Temperatures are generally expected to be mild with readings in

the mid 40s to mid 50s for highs across most Interior locations,

and generally 40-45 degrees near the southern coastal areas.  A

cooling trend is likely by next weekend as the upper ridge axis

breaks down.  The Brooks Range will be the demarcation for much

colder conditions across the North Slope and extending to the

Arctic Coast, with highs struggling to reach the freezing mark

closer to 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



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