Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
600 PM EDT Fri Jun 11 2021
Valid 12Z Tue Jun 15 2021 - 12Z Sat Jun 19 2021
...Guidance/Predictability Evaluation...
The WPC Alaskan medium range product suite was primarily derived
from a blend of reasonably well clustered guidance of the 12 UTC
GFS/ECMWF, 12 UTC GEFS/ECMWF ensemble means and the 19 UTC
National Blend of Models Day 4/Tuesday. Excluded deterministic
models from the composite days 5-8 due to increased variability
and continuity issues with embedded systems compared to yesterday,
lowering forecast confidence. Manually adjustments were applied
mainly to offshore lows to maintain strength consistent with
predictability and upper support to offset weakening inherent to
the blending process.
...Weather/Threats Highlights...
Lingering upper troughing from western to northern Alaska will
support organized precipitation next week, albeit with minimal
activity farther inland under a building/warming Interior upper
ridge. Meanwhile, an active southern branch will progress
near/just south of the Aleutians and a series of complex/uncertain
lows and frontal systems will focus unsettled weather over the
region and downstream across the Gulf of Alaska.
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