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FXAK02 KWNH 072331

PMDAK 



Alaska Extended Forecast Discussion

NWS Weather Prediction Center College Park MD

730 PM EDT Sun Apr 07 2024



Valid 12Z Thu Apr 11 2024 - 12Z Mon Apr 15 2024



...Storm system to bring moderate to locally heavy precipitation

to Western Alaska with Maritime impacts...



...Synoptic Overview...



An amplified trough over the Bering Sea will move through Mainland

Alaska Friday and into the weekend bringing gusty winds, maritime

impacts, and moderate to heavy precipitation. Additional shortwave

energy may briefly close off another upper low in the Gulf this

weekend, keeping conditions unsettled for Southeast Alaska.

General weak troughing will be reinforced over Mainland Alaska

into early next week as another system slides near/just south of

the Aleutians and phases with a second stronger surface low

lifting northward through the north Pacific.





...Guidance Evaluation and Preferences...



The 12z model guidance today shows a good overall depiction of the

synoptic scale pattern through about the first half of the period,

and so a equal blend of the deterministic model solutions was used

for days 4-6. The models today have clustered more towards an

amplified trough moving through the Bering Sea and Mainland late

this week/weekend. There remain some differences in the timing and

details of the system, but higher confidence in some possibly

impactful weather across the Western portion of the mainland.

Shortwave energy rounding the base of the system should allow for

brief surface low development in the Gulf, which looks to quickly

translate eastward. The 12z CMC was an outlier with wanting to

hold back energy or a closed low for longer across the Panhandle.

Compared to yesterday, the guidance has also trended stronger with

a compact system that slides south of the Aleutians this weekend

with plenty of uncertainty in eventual phasing of this with a

larger system lifting northward from around Hawaii early next

week. For days 7-8, increased the ensemble mean usage in the

blend, along with the ECMWF and GFS for some added system

definition.





...Weather/Hazards Highlights...



For Thursday-Friday, a system moving into the Mainland will bring

possible heavy rain/mountain snows across parts of the West, along

with gusty winds and maritime impacts. Farther South general

troughing should keep the Southern Coast/Southeast/Panhandle

generally unsettled much of the period as well. The West may dry

out this weekend, but an additional cold front from the north may

bring another round of rain/snow to parts of northwest Alaska

Sunday-Monday. Temperatures across the southern half of the state

should trend cooler into the weekend as the upper trough moves

through, with the highest anomalies likely across the Southeast.

Northern Alaska should stay warmer than normal the entire period,

but moderating somewhat as additional shortwave energy slides

through the region.



Santorelli





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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