Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 413 PM EDT Tue Oct 30 2018 Valid 12Z Sat Nov 03 2018 - 12Z Wed Nov 07 2018 ...Stormy Weather/Heavy Precipitation Threat for the Alaskan Southern Tier/Maritimes... ...Guidance and Predictability Assessment... The overall pattern remains to be agreed upon especially by the ensemble means with differences in the details. In the beginning of the medium range period, a strong upper low will push across the Aleutians and move into the Gulf of Alaska by later in the weekend. This will give way to a strong occluded system pushing past the Aleutians on Saturday, and moving toward the Alaska Panhandle on Sunday. Height rises are expected especially over the Alaska Panhandle and most of Alaska by the start of next work week. The upper ridge eventually pinches off and moves into the Arctic as height falls over the Bering Sea and western Alaska by midweek--with more zonal flow across the Gulf of Alaska and the Panhandle region. In terms of the blend, the 12Z GFS had considerable differences with individual systems compared to the 00Z ECMWF after Day 4. The 00Z ECMWF ensemble mean and 06Z GEFS mean were comparable--thus these ensemble means were used along with the 00Z ECMWF for detailing as it was more consistent run to run. ...Weather/Hazards Highlights... In the beginning of the medium range period, with that strong occluded system moving across the Aleutians into the Gulf of Alaska, expect higher chances of precipitation along with strong winds--initially in the Aleutians on Saturday. Later on Saturday and into Sunday, expect an increase in precipitation for the Panhandle and coastal British Columbia. Conditions for eastern Alaska become dry especially in the northern and eastern part of the state with the ridge building across the area. As the upper low moves in the Bering Sea on Tuesday and into midweek, chance of precipitation increases once again for Southwest Alaska. A surface trough will linger along south-central Alaska and the Panhandle which may encourage moderate precipitation chances for these areas. High temperatures in north Alaska will remain in the teens to single digits, while Southwest to Southeast Alaska can expect high temperatures in the upper 30s to low 40s. 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