Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 648 PM EST Sun Jan 15 2023 Valid 12Z Thu Jan 19 2023 - 12Z Mon Jan 23 2023 ...Synoptic Overview and Sensible Weather... A broad upper trough is forecast to be in place across much of the Bering Sea and the Aleutians for the end of the week, and a well organized low is expected to track northeastward along the eastern side of the Alaska Peninsula, and likely reaching the vicinity of Kodiak Island by Friday morning. This storm system is forecast to produce moderate to heavy coastal rain and heavy inland snow, mainly from the Kenai Peninsula to the southeast Panhandle, along with gusty onshore winds that may reach 40-60 mph at times. Several inches of liquid equivalent precipitation is likely across the coastal terrain, especially from the eastern Kenai Peninsula to the St. Elias Mountains. Enhanced runoff is expected for the lower coastal elevations. Most of the Interior should remain mostly dry with some light snow in a few locations. Meanwhile, an upper ridge will likely be in place across Yukon and British Columbia for the end of the week before breaking down some for the weekend. The onshore flow will likely keep temperatures relatively mild by January standards across southern Alaska, especially near the coast. The coldest weather is expected to be north of the Brooks Range where subzero high temperatures are likely most days. ...Model Guidance Assessment... The 12Z model guidance suite has a very good overall depiction of the synoptic scale pattern pattern on Thursday across the Alaska domain, but forecast spread increases significantly going into the weekend and beyond. For the storm system approaching the southern Alaska coast late next week, the models are generally well clustered through Friday, with central pressure values near 970 mb Thursday morning followed by steady weakening. Looking ahead to next weekend, models differ quite a bit with shortwave energy and surface lows originating from the far western Aleutians, but there is a decent signal among the deterministic GFS/ECMWF/CMC for a potentially well organized and strong low pressure system to enter the Gulf by next Sunday, with the GFS well to the west of the CMC and ECMWF, and the ECMWF is depicting a weaker system overall. The WPC fronts/pressures forecast is primarily based on a GFS/ECMWF/CMC blend with some ensemble means through Friday, and then gradually increasing use of the ensemble means for the weekend through next Monday time period whilst still maintaining some previous WPC continuity. 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