Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 659 PM EST Wed Nov 08 2023 Valid 12Z Sun Nov 12 2023 - 12Z Thu Nov 16 2023 ***Two intense Bering Sea low pressure systems to monitor with high winds and increasing snowfall chances*** ...Guidance Evaluation and Preferences... The model guidance is in overall good synoptic scale agreement on the main weather systems of interest, and there is above average forecast confidence even going into the middle of next week. The CMC is now more in line with the ECMWF and GFS on the main low pressure systems, although some timing and mesoscale differences remain. The low track for the Bering Sea storm is similar overall compared to yesterday's model runs, although the ECMWF is the stronger solution. The models are also strongly suggesting a stronger low to follow behind it, and the guidance suggests it could take a more southerly track across the Bering with central pressures possibly into the 955-965 mb range. Ensemble means accounted for 30-40% of the forecast blend by next Wednesday and Thursday. ...Overview and Weather/Hazards Highlights... The overall weather pattern across the Alaska domain is forecast to remain quite active for this weekend through the middle of next week, particularly across the maritime regions and the western coast of the mainland. There will be a weakening surface low across the northeastern waters of the Gulf Sunday, with a brief respite before the next low gathers strength in the northern Gulf Monday night. This low is expected to produce a round of moderate precipitation from Kodiak Island to the Kenai Peninsula on Monday, but a greater surge of moisture is expected Wednesday with very heavy mountain snow and over an inch of rain near the southern mainland coast. Things get even more interesting across the Bering and eastern Siberia with two powerful low pressure systems expected. The first storm is forecast to track from the Kamchatka Peninsula to north of the Bering Strait Sunday into Monday afternoon, with gale to storm force winds south of the low across portions of the western Bering and far western Aleutians. Although the greatest impacts are currently expected to remain west of the mainland, portions of the western mainland coast may be impacted by high winds gusting over 40 mph, and the potential for elevated tides also exists. Warm air advection ahead of the storm will likely bring a period of light to locally moderate snow for portions of the western mainland Sunday into early Monday, with several inches of accumulation possible for the some of the Interior valley locations. An even more impactful storm system is appearing on the horizon after this first storm departs, taking a track more southeast compared to the low a few days prior. This would also produce widespread storm force winds, extremely rough seas, and coastal flooding problems. Temperatures are generally expected to be in the 10s to middle 20s for highs across most of the mainland, and 30s for the southern coastal areas and 40s for the Aleutians.. Hamrick Hazards: - Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Wed, Nov 15. - High winds across portions of western mainland Alaska and the Aleutians, Sat, Nov 11. - High winds across portions of western mainland Alaska, Sun, Nov 12. - High winds across portions of western mainland Alaska, Wed, Nov 15. 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