Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 649 PM EST Sun Nov 19 2023 Valid 12Z Thu Nov 23 2023 - 12Z Mon Nov 27 2023 ***Strong winds and heavy precipitation expected for south-central Alaska late next week*** ...Synoptic Overview... A large and powerful low pressure system is expected to be in place just south of the central Aleutians on Thursday, and this low should slowly weaken as it remains nearly anchored in place through early Saturday. This will continue the deep southerly flow from the Alaska Peninsula to the Prince William Sound with multiple rounds of precipitation expected. A second well organized low then enters the western Bering around Saturday night and then tracks generally near or just north of the Aleutians, with more wind and rain expected for those Islands. Meanwhile, a weak upper ridge axis is expected to be in place across the central and northern portions of the mainland going into next weekend. ...Guidance Evaluation and Preferences... The 12Z model guidance suite indicates good overall synoptic agreement through the end of the week and into Saturday. Similar to yesterday, the UKMET was more elongated with the upper low near the central Aleutians for the end of the week and did not align as well with the model consensus, and therefore was not used in the blend for the fronts/pressures. The GFS is a little stronger with an arctic trough crossing the North Slope region, but otherwise matches up well elsewhere through the end of the week. By the weekend, the GFS becomes stronger with the upper ridge centered over the northwestern mainland and forms a closed off high, and it also is stronger over the northern Gulf with a triple point low forming next Monday. The WPC forecast trended more towards the ensemble means for late in the forecast period, though still maintained roughly half of the deterministic guidance (more ECMWF) given the decent agreement and ability to maintain some additional forecast details. ...Weather/Hazards Highlights... The next cold front is forecast to move into the Gulf of Alaska by Thursday, and that is likely to bring another round of gusty winds and heavy precipitation (coastal rain/mountain snow) from the Alaska Peninsula to the southern Coast through Friday. Numerous showers should continue into the weekend within a generally unsettled pattern and onshore flow, with another chance for enhanced precipitation again by Sunday as another storm system enters the Gulf. The low pressure system moving into the far western Bering/Aleutians next weekend will also bring some gusty winds and precipitation to the region. Colder than average temperatures across the state during the short range should moderate some by midweek as the Arctic High slides southeast away from the state. Milder air will also be likely for the south-central portion of the state with more onshore flow and maritime air mass influence. Hamrick 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