Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
553 PM EST Thu Feb 06 2020
Valid 12Z Mon Feb 10 2020 - 12Z Fri Feb 14 2020
Models/ensembles show general consensus that an upper-level ridge
axis across the North Pacific will gradually build northward
across Alaska through the extended forecast period, perhaps
weakening to some degree by the middle of next week in response to
strong incoming shortwave energy in the westerlies. The dominant
storm track will be across the Aleutians and north into the Bering
Sea. Models showed quite a bit of variability with respect to the
evolution and track of a deep low pressure systen near the western
Aleutians on Mon, but the ECMWF seemed to show the most
consistency over the past several runs and was the preferred
solution early in the extended period. This system could produce
strong/high winds across portions of the Aleutians Mon-Tue.
Strong warm advection ahead of this system should spread
additional precipitation across the Aleutians/Alaska Peninsula and
into portions of western mainland Alaska Mon into Tue. Farther
east, another relatively weak wave of low pressure should move
along a lingering frontal boundary in the Gulf of Alaska Sun
night-Mon, bringing a round of precip to the Panhandle/Southeast
Alaska. Models show yet another low pressure system approaching
the western Aleutians by the middle/end of next week. Model
differences on track/timing were a bit higher here, so gradually
increasing emphasis on ECENS/GEFS ensemble means by that time
helped smooth out some of these differences toward a consensus
solution. Given these considerations, the ECMWF was heavily
weighted early in the forecast period, with a gradual trend toward
heavier weighting of ECENS/NAEFS ensemble means through time, and
majority ensemble means after day 6 (Wed).
Ryan
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, Sun-Mon, Feb 9-Feb 10.
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