Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 628 PM EST Mon Feb 20 2023 Valid 12Z Fri Feb 24 2023 - 12Z Tue Feb 28 2023 ...Model Guidance/Predictability Assessment... The 12Z model guidance on most of the synoptic scale features and the ridge/trough evolution across the domain, with the normal level of mesoscale differences. In terms of model differences, the GFS is stronger with the Gulf of Alaska low this weekend, and the UKMET is likely too far south with the low placement. For the potentially significant storm entering the Bering Sea early next week, the GFS has a more southern track and is also south of the GEFS mean, whereas the CMC is suggesting a more northwesterly track near the Siberian coast. The 12Z ECENS is near the overall model consensus and represents a good starting point in regard to this event. The fronts/pressures forecast was primarily derived from the GFS/ECMWF along with some CMC/UKMET for the first half of the forecast period, and then increasing the percentage of the ensemble means to about 50% by next Monday, with more weighting to the ECENS. ...Pattern Overview and Weather/Hazard Highlights... The strong upper ridge axis in place across the Gulf and much of the mainland begins breaking down by Friday as a trough from the Aleutians moves eastward and becomes centered over the Gulf by this weekend, along with a surface low that develops near the southeast Panhandle. A second surface low develops just north of the Aleutians by Saturday morning and steadily tracks eastward before weakening south of the Kenai Peninsula. Looking ahead to early next week, the ridge axis likely rebuilds across the eastern Aleutians and over the western mainland. It is looking more likely that a strong low pressure system will track across the Bering Sea on Monday, with a potential track similar to the event late this week. Periods of moderate to heavy snow are expected across much of the southeast Panhandle on Friday and into Saturday as Pacific moisture advects inland ahead of the Gulf low, with 1 to 2 feet of accumulation possible for the higher elevations. Much of the state should be dry going into the weekend. High winds are a good possibility for portions of the Aleutians Saturday into early Sunday as a low pressure system passes by to the north. The mild temperatures late in the week are forecast to drop substantially from the 20s/30s down to the 0s/10s across much of the mainland for highs going into the weekend as the upper ridge breaks down. The coldest readings are expected north of the Brooks Range, where the greatest coverage of subzero temperatures is likely. Depending on the track and magnitude of warm air advection with the large Bering Sea storm, temperatures are likely to moderate some across the southwestern mainland early next week, along with a return to increasing snowfall chances. Hamrick Hazards: - Heavy snow across portions of central mainland Alaska, Thu, Feb 23. - Heavy snow across portions of the Alaska Panhandle, Fri-Sat, Feb 24-Feb 25. - High winds across portions of northwestern mainland Alaska, Thu, Feb 23. - High winds across portions of coastal mainland Alaska and the Aleutians, Sat, Feb 25. 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