Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 536 PM EST Sun Nov 27 2022 Valid 12Z Thu Dec 01 2022 - 12Z Mon Dec 05 2022 ...Heavy snow/ice and freezing rain threat for Southwest/Western Alaska into the Interior... ...Guidance/Predictability Assessment and Preferences... 12 UTC GFS/ECMWF solutions seem well clustered valid Thursday/Friday in a pattern with above average predictability in line with GEFS/ECMWF ensembles and continuity. Forecast variance/uncertainty with embedded systems, especially at the surface grows quickly next weekend, but guidance does offer a similar larger scale flow pattern aloft. Accordingly, prefer a blend of the GFS/ECMWF and GEFS/ECMWF ensemble means with blend weightings strongly toward the models Thursday/Friday, then transition Saturday to much more emphasis on the ensemble means by next Sunday/Monday. This maintains max WPC product continuity. ...Weather/Hazards Highlights... Models and ensembles agree to sustain an amplified mean upper ridge position up over western Alaska. The ridge will support unseasonably warm conditions over much of the mainland outside of the southeastern Interior and the Southeast Panhandle, with greatest warm anomalies expected from western Alaska through the North Slope next week. This solution is well supported in models and ensembles, bolstering forecast confidence. In this pattern, the progression of the upper trough from the Bering Sea will work through the top of the upper ridge and dig across an unsettled mainland Thursday. Upstream, a deepened cyclone is slated with increased uncertainty to track into the Bering Sea toward Alaska later week into next weekend and act to rebuild western Alaskan ridge amplitude. While there is uncertainty with the interactions of Bering Sea systems moving around or more bodily into the downstream ridge over the mainland late period, the aforementioned preferred guidance composite would highlight shorter range midweek threats for heavy snow/ice and freezing rain across Southwest/Western Alaska into the Interior yet again in particular by Saturday in a pattern periodically channeling system energies and above average moisture into the region. The supporting upper shortwave Saturday now has a more common signal in guidance, bolstering forecast confidence in the threat whose surface pattern may also include some potential for enhanced winds and coastal waves/flooding. Downstream of the upper ridge, cold high pressure will linger over southeastern Interior Alaska valleys and linger across the Panhandle this week with temperatures around 20+ degrees below average over the Panhandle. Additional system energies digging to the lee of the mean upper ridge position should act to maintain unsettled, but still cold conditions over the region through the period. Schichtel 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