Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
251 PM EDT Fri May 24 2019
Valid 12Z Tue May 28 2019 - 12Z Sat Jun 01 2019
Deterministic and ensemble model guidance continues to show good
agreement on the overall synoptic evolution over Alaska through
the medium range period. The upper level pattern favors a blocking
ridge in place over mainland Alaska which allows for a meandering
main cyclone near the central to eastern Aleutians where it
gradually weakens and dissipates. This supports unsettled weather
across much of the Aleutians through most of the period, with
rounds of locally heavy precipitation along the immediate coast.
By the middle of next week the ridge should begin to break down
allowing the trough to expand across the mainland and showers to
expand northward. Farther inland across central to northern
Alaska, mainly showery activity and near normal temperatures are
expected, with above normal temperatures possible along the North
Slope. A blend of the 00z ECMWF/12z GFS and their respective
ensemble means provided a good starting point for today,
maintaining good continuity from yesterday's WPC forecasts.
Increasing contributions from the ensemble means (and less from
the deterministic models) was used later in the period to help
mitigate the differences in the details of individual shortwaves
traversing the larger-scale trough.
Santorelli
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