Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 655 PM EST Wed Nov 9 2022 Valid 12Z Sun Nov 13 2022 - 12Z Thu Nov 17 2022 ...Overview... An upper level ridge is expected to persist over mainland Alaska and northwestern Canada, with shortwaves periodically flowing around or through the ridge. The combination of this ridge and an upper trough/low from the Bering Sea southward through the weekend will favor a persistent flow of moisture into portions of the southern coast and favored terrain over the far southern mainland. By next Monday-Wednesday, the guidance shows a broad area between the western half of the Pacific and Bering Sea where one or more potentially strong storms could develop. ...Guidance/Predictability Assessment and Preferences... The 12Z model guidance suite, along with the 18Z GFS, has decent synoptic scale agreement across the Alaska domain for this weekend. However, more meaningful differences become apparent going forward into late Monday with an arctic shortwave approaching the North Slope region, with the GFS depicting a weak but faster trough passage. The ECMWF is slower and stronger, whilst the CMC has a much weaker disturbance overall. With the much stronger system following behind it from eastern Siberia, the guidance generally agrees that the core of the surface low should pass well to the northwest of the state for the middle of next week, with the ECMWF also slower with this storm. For the closed low that develops south of the Aleutians, the 18Z GFS is slightly north of the model/ensemble consensus, and the guidance generally agrees that this low should drift northward by next Thursday. The WPC fronts/pressures was primarily derived from a multi-deterministic blend through Monday, and then introduced more of the GEFS/ECENS going forward into the middle of the week. ...Sensible Weather and Potential Hazards... Temperatures are expected to generally be in the 20s and low 30s for most of the central/southern mainland earlier in the forecast period, followed by a return to colder weather later in the week as a cold front passes through. Rain chances are expected to be highest from the Alaska Peninsula to the northern portion of the southeast Panhandle, with the potential for several inches of QPF for the Sunday through early Tuesday time period, with this mainly in the form of heavy snow for the higher elevations and heavy rain near the coast as an atmospheric river affects the region. Winds should be highest from the Seward Peninsula to the northwestern mainland Tuesday into early Wednesday, depending on the eventual track and strength of the eastern Siberia storm system. Hamrick Hazards: - Heavy precipitation across portions of the Alaska Panhandle and southern mainland Alaska, Sat-Mon, Nov 12-Nov 14. - Heavy precipitation across portions of southern mainland Alaska, Sat, Nov 12. 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