Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 516 PM EST Sat Nov 18 2023 Valid 12Z Wed Nov 22 2023 - 12Z Sun Nov 26 2023 ...Gusty winds and heavy precipitation expected for south-central Alaska next week... ...Synoptic Overview... Low pressure in the Gulf of Mexico should be weakening by the start of the period on Wednesday while the next storm system slides in just to the south of the Aleutians. Shortwave energy rounding the upper low will reinforce troughing across the Aleutians, pushing a couple of cold fronts into the Gulf and maintaining a steady stream of southerly flow and moderate to heavy precipitation chances into the south-central coast, and at times, the Southeast. A blocky ridge looks to start building across the Panhandle and into eastern Alaska which should eventually force the storm system into the Bering Sea by next weekend. This system should weaken in favor of the next strong system entering the far western domain/Aleutians next Wednesday. ...Guidance Evaluation and Preferences... The 12z model guidance for today continues to show generally good overall synoptic agreement through the entire period. The UKMET was a little more elongated with the upper low near the central Aleutians Wed-Fri and was not used in the blend for the WPC progs. There continue to be some minor timing differences in placement of the upper low and associated shortwave energies/surface fronts, but a general blend of the GFS, ECMWF, and CMC seemed to provide a good starting point for the first half of the period and maintained good continuity with yesterdays WPC forecast as well. By late period, there is some disagreement on the axis and strength of the upper ridge over the Panhandle/East as well as a surface low lifting north from the north Pacific into the Gulf next weekend. Trended towards the ensemble means for the late period, though still maintained slight majority deterministic guidance given the above average agreement and ability to maintain some additional forecast details. ...Weather/Hazards Highlights... Winds and heavy precipitation should be waning by Wednesday as initial low pressure weakens in the Gulf, but may still create some travel impacts leading up to the Thanksgiving Holiday. The next cold front will move into the Gulf by Thursday, likely to bring another round of gusty winds and heavy precipitation (coastal rain/high elevation snow) from the Alaska Peninsula to the southern Coast through Friday. Showers should continue into the weekend within a generally unsettled pattern, with another chance for enhanced precipitation again by Sunday as another possibly cold front enters the Gulf. The next 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. Santorelli 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