Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
621 PM EDT Sun May 15 2022
Valid 12Z Thu May 19 2022 - 12Z Mon May 23 2022
...Overview and Guidance/Predictability Assessment...
An upper level rex block pattern will likely be in place across
western Alaska and the Aleutians for the end of the week, and this
will be slow to change going into next weekend and beyond. By
Saturday, the upper high slowly retrogrades west across the Bering
and an upper trough from the Arctic tries to build in across
eastern Alaska by Sunday and into Monday. Meanwhile, and
organized low pressure system develops over the North Pacific, but
it is currently not expected to make much progress towards the
southern Alaska coast through the weekend.
The 12Z model guidance suite is in good synoptic scale agreement
across much Alaska and vicinity through the end of the work week.
By Saturday, the GFS develops a triple point low over the Gulf
that extends farther north than the other guidance, whilst the
ECMWF is stronger with a surface low over the northern Gulf by
next Monday. The CMC keeps the axis of low pressure farthest
south across the southern Gulf with less in the way of impacts to
the coast. There has been improving model agreement on an
amplifying upper trough over the North Slope and Arctic Coast
region by the weekend. The WPC forecast was primarily derived
from a multi-deterministic model blend through Friday night, with
slightly greater weighting towards the ECMWF/CMC solutions, and
then a gradual increase in the GEFS/ECENS for next weekend whilst
still maintaining some of the deterministic guidance.
...Weather and Hazard Highlights...
Most of the state is expected to remain dry, with the best
potential for some rain across the Aleutians on Friday as moisture
from the offshore low edges north. Some showers are also likely
for the southeast Panhandle for next weekend with onshore flow
ahead of the next storm system. However, the main threat should
continue to be river flooding associated with snow melt and ice
jams. Temperatures across much of the mainland are forecast to
moderate going into the end of the week, with parts of western and
central Alaska and the Peninsula likely having above normal highs
as the Bering Sea ridge slowly works inland. However, a cold
front sinking southward across the northeastern part of the state
by next weekend will likely bring a return to colder weather for
that region.
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