Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
338 PM EDT Thu Jul 12 2018

Valid 12Z Mon Jul 16 2018 - 12Z Fri Jul 20 2018

Guidance is still in decent agreement in terms of timing and
evolution; however, the devil is in the details. The 12Z GFS/00Z
ECMWF/00Z UKMet were similar in timing with the trough and
eventual cut off low moving through the Gulf of Alaska in the
beginning of the week. The ECMWF continues to be more progressive
with the upper low moving into western Canada by midweek and into
late next week. With the upper level trough/system that will move
across the Aleutian Islands, the 00Z ECMWF was also faster than
the 12Z GFS by Thursday/Friday. The 06Z GEFS/00Z ECENS had similar
solutions to the 00Z ECMWF.  Thus, the WPC blend was based on the
12Z GFS/00Z ECMWF/00Z UKMet through Wednesday, and by late week
used more of the 00Z ECMWF and 06Z GEFS/00Z ECENS.

Precipitation chances will increase across the the south-central
coastline of Alaska in the beginning of the week as a trough
skirts along the Gulf of Alaska. As the occluded system moves
across the Aleutians, showers will continue along the
boundary--making it to the eastern edges of southwest Alaska by
Friday.  Height falls in far north Alaska will keep precipitation
chances in the forecast through most of the week. 


Reinhart


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