Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 716 PM EDT Thu Mar 21 2024 Valid 12Z Mon Mar 25 2024 - 12Z Fri Mar 29 2024 ...Guidance Evaluation and Preferences... The 12 UTC GFS/ECMWF/Canadian model solutions are overall well clustered for Monday with good ensemble support. Forecast spread increases through the rest of next week, in particular with respect to the handling of Arctic stream upper low/trough digging into western Alaska to the lee of upstream upper ridging and subsequent interaction and developments with highly energetic Pacific stream energies. This prompted a quick switch to a mainly ensemble mean composite, but kept some influence from the best matching 12 UTC ECMWF to add some detail consistent with predictability. The ECMWF and ensemble means dig Arctic stream energy more than the GFS, but a bit less than the Canadian/UKMET. This maintains max WPC product continuity, but these stream amplitude and phasing issues lower forecast confidence with time. ...Pattern Overview and Weather/Hazards Highlights... Early next week Pacific/Gulf of Alaska system energies and moisture will act to focus lingering wet conditions from the Alaska Peninsula and Kodiak Island through SouthCentral and more modestly into the Southeast before losing influence with southward translation. Coastal rains and inland/terrain snows seem generally moderate by this period. Meanwhile, guidance is trending toward more defined Arctic stream upper trough energy digging down the west coast of the mainland to the lee of initially amplified upper high/ridging upstream. This may possibly lead into closed low undercutting over the Bering Sea, meandering into mid-later next week. This uncertain pattern may look to favor high winds offshore from the Bering Strait to the Bering Sea along with moderate and windy western mainland snow potential aided by uncertain interaction/lifting moisture from southern stream energy. Later, there is an emerging guidance signal to monitor for subsequent development and approach of amplified closed upper trough/low Pacific stream energy and associated deep surface low pressure storm toward the Aleutians in about a week that would offer turbulent maritime conditions and swirling winds and rains. 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 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