Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
400 PM EDT Wed May 22 2019
Valid 12Z Sun May 26 2019 - 12Z Thu May 30 2019
Model guidance continues to show decent agreement on the synoptic
evolution in and around Alaska through the medium range period.
The upper-level pattern continues to favor a blocking ridge over
mainland Alaska and into the Northeast Pacific, as occluded
cyclones track across the central Aleutians and gradually
dissipate in the vicinity of the eastern Aleutians. This will
allow unsettled weather to continue across much of the Aleutians
into the southern part of mainland Alaska. The blocking ridge
over the Northeast Pacific will begin to show signs of breaking
down during the weekend as model ensembles show excellent
agreement on the approach of the next occluded cyclone to the
eastern Aleutians from the south. A consensus of the 00Z EC mean
and the 06Z GEFS together with a small amount of their operational
solutions were used to generate the WPC grids for Alaska for Days
7-8. The operational solutions generally place the center of the
cyclone farther south of the Aleutians than their ensemble means.
The blend of these models yielded solutions that agree very well
with yesterday's WPC forecasts. The resulting cyclone tracks
slightly south of the eastern Aleutians for next Tuesday into
Wednesday, and becomes nearly stationary in that vicinity by next
Thursday. More operational solutions from the 12Z GFS and 00Z
ECMWF were incorporated for Days 4-6.
Kong
Hazards:
-Heavy precipitation across portions of mainland Alaska, Sat-Tue,
May 25-May 28.
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