Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 649 PM EDT Wed Mar 17 2021 Valid 12Z Sun Mar 21 2021 - 12Z Thu Mar 25 2021 ...Overview and Guidance/Uncertainty Assessment... Models and ensembles still offer better than average agreement for the pattern evolution and significant features. A 12 UTC GFS/ECMWF/UKMET/Canadian model blend seems to provide a good representation of the most likely scenario into next midweek, with an ensemble focus day 8. The composites tend to mitigate the less predictable smaller scale differences still inherent with most systems embedded within the larger scale flow. WPC continuity is well maintained. Guidance continues to show a progressive and active pattern across the Bering Sea/North Pacific into the Gulf of Alaska. Expect a lead weekend storm over the Gulf of Alaska, with a subsequent North Pacific storm likely to turn northeastward into the Gulf by early next week. Meanwhile, expect several Bering Sea systems with active weather will work into an unsettled mainland. ...Weather/Hazards Highlights... Lead Bering Sea upper troughing and surface low/frontal system development and onshore track seems likely to spread some organized snows eastward across the Interior and into the Brooks Range/North Slope early next week. Subsequent system energies slated to track across the Bering Sea would bring a front across the southern Bering and Aleutians into midweek, accompanied by precipitation and brisk to strong winds. Less defined late period progression into the western mainland and the Gulf of Alaska would also spread moderate activity across the broad region. A lead and deepened Gulf of Alaska system will focus moderate to terrain enhanced precipitation over the Southeast Panhandle Sunday before exiting the region. Upstream, the Aleutians and Peninsula may see a period of precipitation and enhanced winds early next week on the northwest side of the trailing North Pacific system, but this will be sensitive to the exact track of the surface low. This storm will then quickly bring increasing moisture to the southern coast and especially the Panhandle Tuesday-Wednesday where there is the highest potential for terrain enhancing heavy precipitation given the lower-latitude origin of the moisture. Expect a majority of the state to see below normal temperatures this period with anomalies tending to be colder for daytime highs relative to morning lows (with some pockets of slightly above normal anomalies possible for the latter). Extreme northern areas may see moderately above normal readings. The upper trough arriving into the mainland during the first half of next week should push temperatures somewhat farther below normal compared to the weekend. Schichtel Hazards: - Heavy precipitation across portions of the Alaska Panhandle, Tue, Mar 23. 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