Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 526 PM EDT Mon Apr 20 2020 Valid 12Z Fri Apr 24 2020 - 12Z Tue Apr 28 2020 ...Guidance/Predictability Assessment... A composite blend of reasonably well clustered guidance from the 12 UTC ECMWF/UKMET/Canadian models and GEFS/NAEFS/ECMWF ensemble means along with the 19 UTC National Blend of Models seems to produce a good forecast starting point Friday-Sunday in a pattern with average predictability. The 12 UTC GFS does not seem as well aligned with ensembles. Increased the ensemble mean weightings at longer time frames consistent with growing forecast spread and uncertainty. Manual adjustments were applied to produce sufficiently deep offshore system consistent with favorable upper support, but artificially weakened by the blend process. This forecast maintains good WPC continuity. ...Weather/Threats Highlights... A lead deepened low/frontal system along with an enhanced winds/waves/precipitation remains slated for the Gulf of Alaska into Friday, exiting over the Southeast Panhandle Saturday. Meanwhile upstream, at least two additional emerging frontal systems with deepening lows and enhanced winds/waves/precipitation will dig through the Aleutians and rotate over the Gulf of Alaska to off Southeast and Southern Alaska this weekend and early next week on the heels of the lead system. Farther inland over the state, several unsettling mid-upper level troughs/impulses will work over the North Slope and the Interior over the coming week, significantly cooling the recent warm spell. In this pattern expect some locally/terrain enhanced snows will focus in vicinity of the weaknesses/lows aloft and with a persistent and wavy surface front. Schichtel 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 below normal temperatures across portions of mainland Alaska, Sat-Mon, Apr 25-Apr 27. 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