Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
327 PM EDT Thu Jun 21 2018

Valid 12Z Mon Jun 25 2018 - 12Z Fri Jun 29 2018

Latest models/ensembles were in good enough agreement that a blend
of the GFS/ECMWF and their ensemble means offered a decent
starting point for the Mon-Wed period next week. However, given
the changes from just 24 hrs ago, confidence is average at best
despite the apparent agreement. An upper low is forecast to linger
in the Bering Sea (with a lead surface front) as a Pacific system
rotates underneath it and lifts toward the AkPen later next week.
The GFS was displaced to the east of the best ensemble agreement
(including the ECMWF) by about late Tue into Wed but may not
necessarily be an "outlier" (though the UKMET/Canadian were slower
like the ECMWF). Nevertheless, opted to rely on the larger
ensemble consensus, mostly the 00Z ECMWF ensemble mean, to round
out the forecast which takes the lead system into the Panhandle
next Thursday and the trailing system toward Kodiak next Friday
(perhaps). This will keep the focus for precipitation along the
Aleutians and the southern Kenai peninsula with another focus over
the central/southern Panhandle. The interior will also see some
isolated showers/convection as the ridge axis slides eastward into
Canada and smaller vort maxes lift northward. Temperatures will
generally be within several degrees of average.


Fracasso


WPC medium range Alaskan products including 500mb, surface
fronts/pressures progs and sensible weather grids can be found at:

http://www.wpc.ncep.noaa.gov/alaska/ak_5dayfcst500_wbg.gif
www.wpc.ncep.noaa.gov/alaska/akmedr.shtml
http://www.wpc.ncep.noaa.gov/alaska/ak_5km_gridsbody.html