Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
528 PM EDT Fri May 07 2021
Valid 12Z Tue May 11 2021 - 12Z Sat May 15 2021
...Guidance/Predictability Assessment...
Guidance offers a reasonably similar larger scale pattern
evolution over medium range time scales, but still shows
differences with small-mid scale embedded weather systems,
especially aloft. The 12 UTC GFS/ECMWF/Canadian models are best
clustered days 4-8 and a composite with compatible GEFS/ECMWF
ensemble means and the 19 UTC National Blend of Models seems to
produce a good forecast basis consistent with a pattern with
slightly above normal predictability. This forecast plan maintains
great WPC product continuity.
...Weather/Threats Highlights...
Lead upper trough energies and moderate precipitation focusing
surface lows/frontal weather systems will work from the Aleutians
and the Alaskan Peninsula into the Gulf of Alaska and toward
southern/southeastern Alaska early-mid next week, undercutting a
warming/stabilizing mainland mean upper ridge. Then upstream,
amplified/closed upper trough energy is slated to track over the
southern Bering Sea/Aleutians mid-later next week and deepening
low pressure could support increasingly unsettled maritime
conditions and inland feeding enhanced rains and winds across the
region, then downstream in earnest into the Alaskan
Peninsula/Southwest Alaska/southern Alaska heading into next
weekend. Guidance signal for this low increased over the past few
days, bolstering threat potential.
Schichtel
Hazards:
No significant hazards are expected over Alaska during this
forecast period.
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