Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
619 PM EDT Sat May 08 2021
Valid 12Z Wed May 12 2021 - 12Z Sun May 16 2021
...Guidance/Predictability Assessment...
12 UTC GFS/ECMWF/UKMET/Canadian solutions seem reasonably well
clustered and consistent days 4-6 (Wed-Fri) and enjoy ample
ensemble support, bolstering forecast confidence. The 12 UTC
GFS/ECMWF remain best clustered with the 12 UTC GEFS/ECMWF
ensemble means and the 19 UTC National Blend of Models for next
weekend as well and a composite blend seems to generally produce a
good forecast starting point consistent with a pattern with
overall above normal predictability. This strategy maintains great
WPC product continuity.
...Weather/Threats Highlights...
Upper trough energies and lead/complex precipitation focusing
surface lows/frontal weather systems will work across the Gulf of
Alaska to southern/southeastern Alaska into mid-later next week,
undercutting a warming and stabilizing interior upper ridge.
Meanwhile upstream, amplified/closed upper trough energy is slated
to track over the southern Bering Sea/Aleutians and deepening low
pressure will support increasingly unsettled maritime conditions
and inland feeding enhanced rains and winds across the region.
Activity is expected to translate downstream into Southwest
Alaska, the Alaskan Peninsula, Kodiak Island, the Gulf of Alaska
then southern and southeast Alaska heading into next weekend with
steady main system progression and lead triple point low
developments.
Schichtel
Additional 3-7 Day Hazard information can be found on the WPC
medium range hazards 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