Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
510 PM EDT Sat Jun 01 2024

Valid 12Z Wed Jun 05 2024 - 12Z Sun Jun 09 2024

...Southern Mainland/Interior to Southeast Alaska Heavy
Precipitation Threat into next Midweek...


...Guidance Evaluation and Preferences...

Prefer a composite of reasonably clustered 12 UTC
GFS/ECMWF/Canadian models Wednesday into Friday in a pattern with
slightly above average predictability and identified/collaborated
weather threats. Opted to switch preference to best compatible
GEFS/ECMWF ensemble means onward through next weekend with less
predictable flow details amid growing forecast spread and
individual system uncertainties.

...Weather/Hazards Highlights...

A dynamic/closed upper low tracking to the south of Alaska will
lift into the eastern/northern Gulf of Alaska into Wednesday. This
will support a deepened surface low/system in the Gulf of Alaska
and a period of heavy precipitation and lingering enhanced winds
into Southeast Alaska given some enhanced ex-tropical moisture
influx. Easterly wrapping flow and impulses offer an additional
threat of heavy precipitation into eastern SouthCentral/Alaska
Range along with some enhanced rains into the Interior next week.
Meanwhile, an upper low in the Arctic Ocean to the northwest of
the state looks to send upper low/trough energy southward into the
Bering Sea/West Coast and southeastward through the Aleutians
where there is growing support for a deepened upper low/surface
lows later next week, while several weaker shortwaves traverse the
southern side of this mean troughing south of the Aleutians and
towards the Gulf. Over the Mainland itself, upper ridging should
build warming.

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