Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
627 PM EDT Sat May 14 2022
Valid 12Z Wed May 18 2022 - 12Z Sun May 22 2022
...Overview and Guidance/Predictability Assessment...
A rather amplified upper level pattern is expected across the
Alaska domain for the middle to end of next week, with a closed
upper high over the Bering remaining nearly anchored in place,
with a potential rex block developing by the end of the week as an
upper low develops to its south. Some upper level troughing will
likely be in place across the Arctic Coast region at the beginning
of the forecast period. At the surface, a low pressure system
over the eastern Gulf will gradually weaken and move inland by
Wednesday, while a broader, elongated low develops over the North
Pacific.
The 12Z model guidance suite is in good synoptic scale agreement
across much Alaska and vicinity through the end of the week. Both
the UKMET/GFS have trended stronger regarding the extent of the
upper ridge across the Aleutians/Bering compared to yesterday's
runs. The CMC/GFS are stronger with a trough crossing northern
Alaska by Friday and into Saturday compared to the ECMWF, and
there is still good consensus for a southeast-northwest oriented
ridge axis across the southwestern mainland through next weekend.
The WPC forecast was primarily derived from a multi-deterministic
model blend through early Friday, 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 passing showers across the Aleutians later in
the week. However, the main threat should continue to be river
flooding associated with snow melt and ice jams. Temperatures
across much of the mainland for the middle of next week are likely
to start off a bit below normal, with the greatest anomalies for
eastern Alaska as a deeper shortwave exits the region.
Temperatures are forecast to moderate going into the end of the
week, with parts of western Alaska and the Peninsula likely having
above normal highs as the Bering Sea ridge slowly works inland
next week.
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