Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 522 PM EST Wed Dec 14 2022 Valid 12Z Sun Dec 18 2022 - 12Z Thu Dec 22 2022 ...Interior to Panhandle cold wave with some record values possible... ...Guidance/Predictability Assessment and Preferences... 12 UTC GFS/ECMWF/UKMET/Canadian solutions seem well clustered through Sunday/Monday and a favored composite is well supported by ensembles, bolstering forecast confidence. Prefer to then transition guidance preference to the 12 UTC GEFS/ECMWF ensemble means amid growing variance with embedded systems within a still reasonably similar larger scale flow evolution. Accordingly, above average product continuity and predictability lowers to average levels Tuesday onward. WPC product continuity is reasonable with this WPC/Alaskan office collaborated forecast plan. ...Pattern Overview and Weather/Hazards Highlights... A strong and shielding mid-upper level ridge axis is forecast to build northward across much of the western mainland and the eastern Bering Sea for the weekend as shortwave energies dig sharply to the lee of the ridge over a frigid eastern mainland and eastern Gulf of Alaska/Southeast Panhandle. Strong surface high pressure spilling from over the Interior and Yukon (center upwards of 1060mb) will maintain much below normal to local record temperatures across the region and into the Southeast Panhandle. Minimum temperatures may fall into the -40 to -50 F range in the colder spots of the eastern Interior and into the zero to -10 F range over favored spots of the Southeast Panhandle. These values This pattern also seems favorable for periods of enhanced gap winds in favored spots across the region to be monitored. The main upper ridge may lose some integrity into next week with recent guidance solutions varied with extent that the northern portion develops a closed high over the Chukchi Sea as uncertain upper shortwave energies divert/undercut over the Interior, but latest solutions now offer more similar upper trough undercutting energy focus into south-central Alaska that may also allow a modest northern Gulf surface low/coastal precipitation next week. The main Pacific low storm track and most precipitation is held to the south of the state in guidance through this forecast period, but wrapping flow will still affect the Aleutians/AKpen as a building upper trough nudging into the region/southwestern upper ridge periphery likely supports windy/deepened maritime surface lows with moderate onshore precipitation. Schichtel Hazards: - Much below normal temperatures across portions of the Alaska Panhandle and mainland Alaska, Sat-Tue, Dec 17-Dec 21. 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