Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 335 PM EDT Wed Mar 13 2019 Valid 12Z Sun Mar 17 2019 - 12Z Thu Mar 21 2019 The latest guidance persists in showing a multi-day signal of several inches of QPF along the southern coast of the Mainland and northern portions of Southeast Alaska as a series of lows lift northward through the Gulf of Alaska. The air mass will quickly lose its moisture content farther inland, however, with relatively dry conditions expected to persist across the Interior and the North Slope. The continuous track of storm systems across the Gulf into southern Alaska, and the persistent deep southerly flow will make for a period of widespread and occasionally heavy precipitation for many areas from southern mainland Alaska to Southeast Alaska. Additionally, the weekend system may bring the potential for high wind gusts to southern mainland Alaska, particularly for coastal areas. Confidence remains fairly high that multiples systems within the atmospheric river will result in well above normal amounts of precipition - daily totals averaging 2 to 4 inches with 5-day totals of 10 to 20+ inches possible. Days 4/5 blend consisted of a multiple model approach given the waviness of the pattern. The CMC and UKMET were not overly useful for Days 6 and beyond so therefore they were not utilized. The later peiods had heavier weighting of the ensemble means with some of the ECWMF/GFS incorporated. Campbell Bullet points from the WPC Days 3-7 Hazards chart: https://www.wpc.ncep.noaa.gov/threats/threats.php - Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Sat-Tue, Mar 16-Mar 19. - High winds across portions of the Alaska Panhandle and mainland Alaska, Sat-Tue, Mar 16-Mar 19. WPC medium range Alaskan products including 500mb, surface fronts/pressures progs and sensible weather grids can 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