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FXAK02 KWNH 292117

PMDAK 



Alaska Extended Forecast Discussion

NWS Weather Prediction Center College Park MD

516 PM EDT Mon Apr 29 2024



Valid 12Z Fri May 03 2024 - 12Z Tue May 07 2024



...Aleutians to Gulf of Alaska Storm Threat Thursday to Sunday...





...Guidance Evaluation and Preferences...



Latest 12 UTC ECMWF/UKMET/Canadian and to a slightly lesser extent

the 12 UTC GFS model solutions remain well clustered and supported

by multi-model ensembles Friday into Sunday in a pattern with

above normal predictability. A composite solution provides a solid

forecast basis and detail. Prefer best clustered ECMWF/Canadian

ensemble means into longer time frames to offer maximum system and

WPC product continuity.  Manually applied adjustments offset

system weakening inherent to the blending process due to growing

displacement variances.



...Weather/Hazards Highlights...



A low pressure system with supporting/amplified upper trough

support in a recent series will progress southeastward across the

Gulf of Alaska into late week and favor areas of enhanced maritime

winds/waves and precipitation that should also linger inland

across coastal areas of the southern to southeast tier of the

state to produce some terrain focusing some moderate

precipitation.



A portion of the state will experience above seasonal average

temperatures for the start of the month, particularly portions of

the southern Interior where anomalies will be the highest. There

is some risk there for enhanced downslope winds off the Alaska

Range into drying soils to monitor for wildfire hazards.

Additional upper troughing over the Arctic Ocean is expected to

also settle down into the northern tier of the state then dig into

the Bering Sea into next week. In this pattern, areas to the north

of a surface front settling over the northern and central mainland

in cold high pressure should keep temperatures below normal,

especially across the unsettled North Slope and northern Interior.

Guidance still shows spotty/unsettled light precipitation.



Meanwhile, guidance continues to highlight development of a much

deeper low pressure system to affect the Aleutians and Bering Sea

with potentially high winds by midweek. This deepened low offers a

potentially hazardous multi-day period with enhanced wind

flow/waves and precipitation set to work downstream. Steady

progression of this well organized/deep storm within the amplified

pattern will lead to enhanced lead inflow to fuel precipitation

into West and Southwest Alaska into Saturday. Ample Gulf of Alaska

redevelopment should offer renewed maritime hazards along with

moderate to heavy multi-day precipitation inland for the Alaska

Peninsula/Kodiak Island and then SouthCentral to Southeast Alaska

this weekend into early next week.



Upstream, the later period settling of northern stream upper

trough energy into the Bering Sea and subsequent progression of

additional North Pacific system energies may lead to track and

development of another Aleutians organized low pressure/frontal

system to focus winds/waves and rainfall early next week.



Schichtel





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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