Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 633 PM EST Wed Jan 29 2020 Valid 12Z Sun Feb 02 2020 - 12Z Thu Feb 06 2020 Upper pattern will largely maintain troughing in the Bering Sea into western Alaska with ridging east of about 150W. Within that orientation, several features will propagate through the North Pacific and Gulf and try to bring in milder temperatures to at least southwestern areas of the mainland. Precipitation focus will lie primarily along/east of the Kenai peninsula and especially into the Panhandle given the continued onshore flow. Second area will be over southwestern/western Alaska as low pressure weakens on Monday. The 12Z guidance came into very good agreement for the rather complicated pattern, but with the ECMWF leading the way in run-to-run continuity, opted to use a deterministic blend for the Sun-Tue period. Ensemble means may be lagging behind the deterministic runs in the evolution of the lead system, in particular the old parent low that is forecast to wrap back to the east and northeast as northern stream energy rotates around the backside of the main weakening upper low. This scenario was contingent upon a couple things coming together but the several runs of the guidance in that fashion suggest it has some merit. For next Wed/Thu, the 12Z GFS/Canadian/ECMWF were nearly in line taking that low into the AKPEN and then Gulf with its frontal system approaching the Panhandle. To the west, better agreement exists between the models and ensembles with another system of modest strength near the western Aleutians. Temperatures will moderate from well below average to within several degrees of average over portions of at least southwestern Alaska, but how quickly that happens is uncertain. The dense cold air may be reluctant to budge at the surface despite increased southerly flow aloft. Again trended a bit slower to raise temperatures than the NBM or most guidance. Precipitation will be favored along the coast from the Aleutians eastward. Several inches of liquid equivalent (~3-5") are possible for the Panhandle, especially from Yakutat southward along the coastline. Fracasso 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 mainland Alaska and the Aleutians, Sun, Feb 2. - Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Mon-Tue, Feb 3-Feb 4. - High winds across portions of mainland Alaska and the Aleutians, Sat-Sun, Feb 1-Feb 2. - Much below normal temperatures across portions of mainland Alaska, Sat-Mon, Feb 1-Feb 3. - High significant wave heights for coastal portions of mainland Alaska and the Aleutians, Sun-Mon, Feb 2-Feb 3. 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