Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
632 PM EDT Mon May 31 2021
Valid 12Z Fri Jun 04 2021 - 12Z Tue Jun 08 2021
...Overview and Guidance Evaluation...
The upper level pattern is forecast to evolve from large scale
troughing over much of the region with embedded closed lows to
more quasi-zonal fast flow by early next week. The main/deeper
surface low in the Gulf of Alaska at the start of the period is
expected to weaken as it moves east/southeast. In its wake, a
couple of weaker lows will pass through the Mainland which will
keep weather unsettled but lack any significant systems or
sensible weather impacts. The model guidance was reasonably
clustered at the start of the period though the GFS, both the 06Z
and 12Z runs, were noted to be faster with the evolution of the
closed lows in the southern portion of the larger trough. The WPC
forecast was primarily derived from a blend of the 12Z
ECMWF/GFS/CMC/UKMET through Saturday, and then more of the
ensemble means for Sunday through Tuesday.
...Weather/Threats Highlights...
The persistent low pressure and onshore flow from the Alaska
Peninsula to the southeast panhandle region through the end of the
week is expected to produce multiple rounds of light to moderate
rainfall for coastal areas and nearby mountain ranges. Somewhat
drier conditions are possible later in the weekend and into early
next week but there remains uncertainty given the faster flow
pattern in place. The highest rain chances days 6-8 will be across
portions of the interior Alaska. Temperatures are expected to
reach the 60s across much of the Interior for highs, and remaining
quite chilly north of the Brooks range where highs should remain
in the 30s and 40s.
Taylor
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