Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 605 PM EST Fri Jan 24 2020 Valid 12Z Tue Jan 28 2020 - 12Z Sat Feb 01 2020 ...Well below average temperatures for most of mainland Alaska... ...Active pattern with two deep Gulf of Alaska storms bring heavy precipitation to portions of Alaska Panhandle and mainland next week... Through next week, the latest models and ensemble guidance continues to show average to above average consensus featuring an upper level ridge building to the west of Alaska and only gradually weakening/shifting west through the forecast period. Forecast confidence is high for a cold surface airmass settling across much of Alaska well into next week. An active North Pacific jet will send various shortwaves/surface lows across the North Pacific into the Gulf of Alaska, one such wave will deepen considerably over the northern Gulf Tuesday into Wednesday. Low depth has trended deeper than yesterday and that seems reasonable considering support. A second deep low then lifts quickly towards Southeast Alaska, keeping relatively high precipitation chances in the forecast through much of the forecast period. Low depth has trended deeper than yesterday and that seems reasonable considering support and much better guidance support. Lingering deep layered cold air and proximity to the surface low in place will support locally heavy snows through lower elevations of southern Alaska and the northern Panhandle. The 12Z deterministic guidance showed fairly high agreement through Day 4-5 with slowly increasing model spread seen beyond through the end of the forecast period. The WPC blend incorporated primarily the 12Z GFS/ECMWF with higher weights of the 12Z GEFS/NAEFS for Day 6-8. This approach accounted for changes seen in the evolution of the Southeast Alaska low by the middle/latter portions of the forecast period while maintaining some aspect of continuity given the model spread/uncertainty. Taylor/Schichtel Additional 3-7 Day Hazard information can be found on the WPC medium range hazards chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php Hazards: - Heavy precipitation across portions of the Alaska Panhandle, Thu-Fri, Jan 30-Jan 31. - Heavy snow across portions of the Alaska Panhandle and mainland Alaska, Mon-Wed, Jan 27-Jan 29. - High winds across portions of the Alaska Panhandle, mainland Alaska, and the Aleutians, Mon-Fri, Jan 27-Jan 31. - Much below normal temperatures across portions of mainland Alaska, Mon-Wed, Jan 27-Jan 29. 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