Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 521 PM EDT Sat Apr 18 2020 Valid 12Z Wed Apr 22 2020 - 12Z Sun Apr 26 2020 ...Overview and Guidance Evaluation and Weather/Threats Highlights... The primary weather threats will be mainly for maritime interests next week, with less active flow for much of Alaska. System potential and lingering guidance uncertainties focus well to the south of the Aleutians and the Alaskan Peninsula as organized/slow evolving lows settle over the region and reform into the Gulf of Alaska. The lows have trended somewhat farther offshore compared to yesterdays guidance. In this pattern moisture will tend to reach toward the Southern and Southeast Alaskan coasts as main cyclones and frontal systems spin well offshore. However, a lead wave could bring a higher chance of precipitation into southern and southeastern Alaska through midweek, with best potential for heavier amounts over favored Southeast terrain in onshore flow. Farther inland over the state, several unsettling mid-upper level troughs/impulses will dig over the North Slope and Interior over the coming week, cooling the current warm spell. In this pattern expect modest precipitation will focus in vicinity of the weaknesses/lows aloft and a lingering and wavy surface front. Overall, a blend of 12 UTC GFS/ECMWF, 12 UTC GEFS/ECMWF ensemble means and the 19 UTC National Blend of Models seems to produce a good forecast starting point for the day 4-8 period. Opted to increasingly weight the ensemble means into longer time frames consistent with growing forecast spread. Even so, the deterministic models provide some enhanced detail days 4-8 consistent with a pattern with at least average predictability. Manual adjustments were then applied to produce sufficient offshore system depths consistent with upper support, but artificially weakened by the blend process. This Alaskan office/region collaborated forecast strategy maintains great WPC continuity. 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 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