Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 527 PM EST Fri Jan 13 2023 Valid 12Z Tue Jan 17 2023 - 12Z Sat Jan 21 2023 ...Synoptic Overview and Sensible Weather... A fairly progressive flow pattern is expected to be in place across the northern Pacific next week, and a broad upper trough over the Bering Sea and western Alaska, and upper level ridging then builds across western Canada by Friday and next weekend. At the surface, a well organized low is expected to track northeastward southeast of the Aleutians and likely reaching the vicinity of the northern Gulf by Friday. This storm system will likely produce moderate to heavy coastal rain and inland snow, mainly from the Kenai Peninsula to the southeast Panhandle, along with gusty onshore winds that may reach 40 mph at times. Most of the Interior should remain dry with perhaps some light snow in a few locations. The onshore flow will likely keep temperatures slightly above average across southern Alaska, and near to below average for the Interior and the North Slope. ...Model Guidance Assessment... The 12Z model guidance suite has a good overall depiction of the synoptic scale pattern pattern on Tuesday, although the GFS is a bit more progressive and stronger with the trough crossing the southern Gulf through Wednesday. The CMC becomes considerably stronger with an upper low over the northern Bering late in the forecast period that does not appear to have much support from the ensemble means. For the storm system approaching the southern Alaska coast late next week, the models are generally well clustered through Thursday, and the GFS is slightly faster than the ECMWF and generally close to their respective ensemble means, whereas the CMC is more elongated with the low. The WPC fronts/pressures forecast is primarily based on a GFS/ECMWF/CMC blend with some ensemble means through Wednesday, and then less of the CMC and more of the GFS/ECMWF along with increasing use of the ensemble means for the Thursday through Saturday time period. Hamrick Hazards Highlights: - Heavy precipitation across portions of southern mainland Alaska, Mon-Tue, Jan 16-Jan 17. - Heavy precipitation across portions of the Alaska Panhandle and southern mainland Alaska, Fri, Jan 20. 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