Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 500 PM EST Sun Jan 14 2024 Valid 12Z Thu Jan 18 2024 - 12Z Mon Jan 22 2024 ...Guidance Evaluation/Preferences... Guidance remains well clustered in a pattern with much above normal predictability Thursday into Saturday. A 12 UTC GFS/ECMWF/UKMET/Canadian blend seems to mitigate differences reasonably and still provide good detail. Opted to then switch to the 12 UTC GEFS/NAEFS/ECMWF ensemble means amid growing forecast spread to maintain max WPC product continuity. Predictability slowly decreases through these longer time frames due to uncertainties with any retrogression/weakening of the main upper ridge/closed high that tend to persist in blocky flow and also with how the downstream digging and undercutting of northern stream energy over the mainland into the Gulf of Alaska interacts with slowly northward lifting and rotating Pacific system energies and moisture. Overall, planned manual adjustments should better link precipitation and probabilities and precipitation to forecast wind flow and also act to provide sufficient wind speeds to offset weakening from the blending process. ...Weather/Hazards Highlights... Expect a trend to colder temperatures for this forecast period for much of the state. Periodic unsettled and locally snowy/gusty periods may develop later week into next as energies digs sharply through the eastern mainland and into the Gulf of Alaska to the lee of the upstream and amplified Bering Sea centered upper high/ridge that will anchor a slow to dislodge blocky flow pattern for Alaska and vicinity. Upper trough system energies offer some timing/strength challenges, but seem likely to periodically focus enhanced winds/tighter pressure gradient gap winds and snows later week through the weekend from the North Slope/Brooks Range and eastern Interior down through the Alaska Range/SouthCentral Alaska to the Gulf of Alaska and the Southeast as colder air settles in and pressure gradients tighten. Closed northern stream upper low/trough and slow meandering/undercutting over the Gulf of Alaska along with also less certain interactions with southern stream Pacific system energies remain problematic for local focus, but overall show ample support to maintain and focus protracted and widespread maritime wind/wave impacts offshore and a renewed Southeast Alaskan precipitation trend over time. 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