Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 633 PM EST Wed Jan 05 2022 Valid 12Z Sun Jan 09 2022 - 12Z Thu Jan 13 2022 ...Stormy Pattern For Alaska... ...Overview... It pretty much remains the case that a blocky and persistent upper upper ridge over northeastern Russia/the Bering Sea should finally weaken some and retreat westward during the medium range period. This will lessen its influence on Alaska and allow for lower mid-upper heights to come into the state, with a busy storm track situated near/south of the Aleutians and the northern Pacific/Gulf of Alaska. This will favor increasing moisture and brisk winds into southern parts of Alaska from the Aleutians into Southcentral Alaska and the Panhandle by the weekend through mid next week. ...Guidance Evaluation and Preferences... The latest model guidance, particularly the ensemble means, continue to show good agreement on the overall synoptic scale pattern, but increasing uncertainty in the details. Nearly all of the models agree that a blocky high over northeast Russia should retreat westward by Saturday as an upper low retrogrades westward across the warming mainland Alaska and into the southeast Bering through Sunday. South of the Aleutians and into the Gulf of Alaska however remains rather chaotic as the models struggle to resolve details surrounding multiple streams/surface lows rotating around a main region of upper level low pressure. Eventually, mainland system energy should merge into the broader low south of the Aleutians, creating a persistent plume of moisture directed towards southern and southeastern Alaska. Model guidance varies to with the timing, strength, and placement of the surface lows/frontal systems. However, there has been a favorable trend in that the 12 UTC ECMWF/Canadian now seem reasonably well clustered with GEFS/NAEFS/ECMWF ensemble means. The GFS tends to be an outlier with some embedded systems. Accordingly, the WPC Alaskan medium range product suite was primarily derived from a blend of the 12 UTC ECMWF/Canadian and 12 UTC GEFS/NAEFS/ECMWF ensemble means along with large input from the seemingly reasonable 19 UTC National Blend of Models due to continuing guidance access issues at WPC and beyond. ...Weather/Hazard Highlights... It also generally remains the case that increasing moisture is likely by the weekend across south-central Alaska and the Panhandle as lead flow from low pressure over the northern Pacific, works across the Gulf. The frontal system should help direct a persistent plume of deep Pacific moisture towards the region Sunday-Wednesday. There's a pretty decent signal in the guidance for a potentially significant precipitation event, with multiple days of moderate to heavy precipitation from roughly Kodiak Island to much of the Panhandle. A strong pressure gradient setting up between low pressure in the Gulf and high pressure to the north of Alaska by early next week will result in very windy conditions. Additional low genesis is likely for the Gulf into mid-late week. Elsewhere across Alaska, the weather should generally be dry, with the exception of a few light showers across higher terrain inland. The Aleutians should also remain rather unsettled and wet through the weekend under the influence of low pressure south of the region. Temperatures across the state should start out chilly and much below normal, especially across western and eastern Alaska where daytime highs could be 20-30 degrees below normal. However, by early next week, temperatures should quickly moderate to above normal across much of the state, except the North Slope region which remains stuck beneath surface high pressure through much of 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 Hazards: - Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Sat-Wed, Jan 8-Jan 12. - High winds across portions of the Alaska Panhandle and mainland Alaska, Sat-Sun, Jan 8-Jan 9. - Much below normal temperatures across portions of mainland Alaska, Sat-Sun, Jan 8-Jan 9. - Much below normal temperatures across portions of mainland Alaska, Sat, Jan 8. 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