Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 659 PM EST Fri Feb 24 2023 Valid 12Z Tue Feb 28 2023 - 12Z Sat Mar 04 2023 ...Heavy precipitation expected from southwestern Alaska to the Panhandle early to middle of next week... ...Pattern Overview, Model Guidance/Predictability Assessment and Weather/Hazard Highlights... Model guidance today continues to show further adjustments to the track of an occluded cyclone forecast to approach southwestern Alaska early next week. After the GFS showed a significant northward adjustment to the cyclone forecast track away from the Aleutians yesterday, the ECMWF today showed a significant slowdown as well as southward adjustment to the forecast track. Thus, their forecast tracks have generally converged toward the central Bering Sea early on Tuesday, with the GFS/GEFS being on the slow side of the guidance. The CMC still indicates a faster and northern-most track for this system. The overall slower progression of the main low across the Bering Sea appears to allow a triple-point low to better develop near the Alaska Peninsula later on Tuesday. Models have generally trended heavier with the precipitation reaching into southwestern Alaska ahead of the system on Tuesday, and there appears to be opportunity for a period of moderate to heavy mixed precipitation to impact the coastal sections while snow spreads farther inland Tuesday and Tuesday night. The GFS is the most enthusiastic in this regard. Thereafter, the triple-point low is forecast to become the dominant low just off the southern coast of Alaska by Wednesday. Heavy precipitation can be expected to spread from west to east along the southern periphery of Alaska the next couple of days. Snow is currently forecast for much of the region even for the coastal sections, although rain may mix in initially at the immediate coast. Heavy snow could extend farther inland from the southern coast, although our latest precipitation estimates indicate the highest QPF will be over portions of southwestern Alaska late Tuesday/Tuesday night. In addition, very gusty winds appears likely on the backside of the system across the Alaska Peninsula and nearby islands into the eastern Aleutians. Thereafter, models are in relatively good agreement for heavy precipitation to impact the Panhandle late Wednesday into Thursday, with the southern portion of the Panhandle having a better chance of seeing mixed precipitation. By next Friday, models agree that a drying trend should set in as the coastal system degenerates. The WPC fronts and PMSL forecasts were derived mainly from the 12Z ECMWF, 00Z and 12Z EC mean, the 12Z GFS and GEFS, with smaller contributions from the 12Z CMC and CMC mean. The results show a notable southward adjustment to the cyclone track across the Bering Sea into western Alaska Tuesday and Wednesday (Day 4 & 5). The rest of the forecast days are quite compatible with WPC continuity. Kong Hazards: - Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Tue-Wed, Feb 28-Mar 1. - Heavy snow across portions of mainland Alaska, Tue-Wed, Feb 28-Mar 1. - High winds across portions of mainland Alaska and the Aleutians, Wed-Thu, Mar 1-Mar 2. - Much below normal temperatures across portions of mainland Alaska, Mon, Feb 27. 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