Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 547 PM EDT Fri Apr 17 2020 Valid 12Z Tue Apr 21 2020 - 12Z Sat Apr 25 2020 ...Overview and Guidance Evaluation and Weather/Threats Highlights... The main weather threats should be for maritime interests next week, with benign flow for much of Alaska. System potential and lingering guidance uncertainties focus 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. In this pattern moisture will tend to reach the Southern and Southeast Alaskan coasts as main cyclones spin offshore. 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. Guidance is more agreeable farther inland over the state. An amplified upper ridge built up through the Interior over the short range will be replaced by a unsettling mean weakness aloft through medium range time scales. This will moderate the current warm spell in a pattern with modest precipitation potential that may focus in vicinity of the weakness/low aloft and a lingering and wavy surface front. Overall, a composite blend of 12 UTC GFS. 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. Of the deterministic models, the GFS seems best clustered with the ensemble means and provides some enhanced detail consistent with a pattern with average to above 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 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 Hazards: No significant hazards are expected over Alaska during this forecast period. 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