Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 759 PM EDT Wed May 17 2023 Valid 12Z Sun May 21 2023 - 12Z Thu May 25 2023 ...Spring warming to advance interior snowmelt runoff and river ice breakup and flooding threats this week... ...Guidance Evaluation/Predictability Assessment... The medium-range period will likely feature a zonally-oriented upper ridge across the northern and eastern Alaska while various vorticity centers will attempt to merge and/or rotate about a mean center near/over the Aleutians. This pattern will continue to contribute to below normal predictability for areas south of the relatively stable and more predictable upper ridge. The first system of concern should be pushing north into the eastern Aleutians and the Alaska Peninsula this weekend as it rapidly weakens. Farther upstream, model consensus today indicates a stronger and more consolidated cyclone to approach the central Aleutians from the south by next Monday. ...Overview and Weather/Hazard Highlights... The upper level ridge situated across much of the mainland and into western Canada will keep pleasantly mild temperatures in place going into the weekend and into early-mid next week. High temperatures well into the 60s and low 70s are expected for the lower elevations of the Interior and overnight lows generally in the 40s. The mountains will also have mild conditions and this will continue the snow melting process and ice break-up on area rivers, with the potential for river flooding. A weakening surface low is forecast to move into the eastern Aleutians and the Alaska Peninsula this weekend, followed by another low pressure system that will bring the next round of precipitation to the eastern Aleutians and the Alaska Peninsula early next week, and then tapering off going into mid-week. Overall, no big storms are anticipated to impact Alaska through the medium-range forecast period. Hamrick Hazards: - Heavy precipitation across portions of mainland Alaska and the Aleutians, Mon-Tue, May 22-May 23. - Flooding possible across portions of mainland Alaska, Sat-Wed, May 20-May 24. Additional 3-7 Day Hazard Information can be found on the WPC medium range hazards outlook 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