Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
544 PM EST Thu Nov 14 2019
Valid 12Z Mon Nov 18 2019 - 12Z Fri Nov 22 2019
...Aleutians to Gulf of Alaska Stormy Pattern...
...Guidance/Uncertainty Assessment and Weather
Highlights/Threats...
Ensemble model guidance seems fairly well clustered through next
week with the overall pattern evolution and for the most part, a
number of potentially well-organized weather focusing systems.
Unsettling mid-upper level troughing should hover across southwest
Alaska towards the North Slope, with limited moisture and lift
supporting periods of snow for the region in gradually easing
low-level easterly flow.
Meanwhile, a leading deep surface low should move from the western
Aleutians towards the southern Bering Mon-Wed with a second system
following mid to late next week along roughly the same trajectory.
Both of these systems pose a maritime threat for high winds/waves,
with moisture expected to wrap onshore sustaining some threat of
locally heavy precipitation for coastal areas and especially the
favored terrain. The WPC blend for today favored mostly
deterministic (GFS/ECMWF) models for days 4-5, with increasing
ensemble mean support through day 8 amid growing model forecast
spread with individual systems. This maintains good continuity
with the previous shift as well.
Santorelli
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
Hazards:
- Heavy precipitation across portions of the Alaska Panhandle and
mainland Alaska, Tue-Thu, Nov 19-Nov 21.
- Heavy snow across portions of mainland Alaska, Tue-Wed, Nov
19-Nov 20.
- High significant wave heights for coastal portions of the
Aleutians, Mon-Tue, Nov 18-Nov 19.
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