Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
626 PM EDT Fri May 29 2020
Valid 12Z Tue Jun 02 2020 - 12Z Sat Jun 06 2020
...Overview and Weather Hazards/Threats...
A mid/upper-level ridge centered across the Beaufort Sea/Arctic
Ocean is expected to slowly weaken and meander in place through
the period. The ridge will promote well above average temperatures
for western mainland Alaska into parts of the Interior through
early next week. High temperatures will range from 5 to as much as
20 deg F above average (into the 70s for some locations). To the
south, the flow across the North Pacific will ride the
west-to-east jet with a lead defined system exiting the region
after Tuesday. This will bring rain and some mountain snow to
southeastern areas and especially the Panhandle. Amounts may be
modest in some locations but generally not heavy.
...Guidance/Predictability Assessment...
Latest 12Z guidance has come into better agreement on the timing
of the lead system south of the AKPEN, with lingering timing
differences represented by a consensus solution between the 12Z
GFS and ECMWF. The models/ensembles showed good agreement to the
north with the nearly stationary upper high, but struggled with
the smaller-scale shortwaves out of the Bering and across the
Aleutians. It was here than even the ensemble members differed
noticeably on timing but mostly agreed on lower amplitude features
(perhaps manifested at the surface by a cold front but depicted as
weaker surface troughs for now). Consensus blend approach was
sufficient given the lower predictability.
Fracasso
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:
- Much above normal temperatures over the Seward Peninsula in
western Alaska, Mon, Jun 1.
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