Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
557 PM EST Mon Feb 08 2021
Valid 12Z Fri Feb 12 2021 - 12Z Tue Feb 16 2021
...Guidance/Uncertainty and Weather/Hazards Assessments...
A mean ridge axis is slated to build in over the state from the
northeast Pacific in a generally moderating pattern. Meanwhile, a
stormy weather pattern focus is likely across the southern Bering
Sea and the Aleutians as a couple of Pacific storm systems pass
through that region as they rotate with a broader upper level
gyre. Timing issues remain, but system potential is heightened for
these main lows whose wrapping flow will threaten the Aleutians
and the AKPen/Kodiak and vicinity Friday and the weekend.
Additional system activity to the east seems more modest/offshore
out over the Gulf of Alaska for the next week.
12 UTC GFS/ECMWF solution are well clustered enough that a blend
seems to offer a decent forecast for day 4/Friday. Model forecast
spread increases quickly from the weekend into next week.
Predictability decreases, but the mainly compatible GEFS/ECMWF
ensemble means seemingly then provide a reasonable larger scale
flow evolution. Accordingly, the WPC Alaskan medium range product
suite was primarily derived from a blend of these ensemble means
and the 19 UTC National Blend of Models to maintain max WPC
continuity.
Schichtel
Hazards:
- Heavy precipitation across portions of mainland Alaska, Thu, Feb
11.
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