Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 509 PM EST Mon Jan 15 2024 Valid 12Z Fri Jan 19 2024 - 12Z Tue Jan 23 2024 ...Cold trend statewide over the next week with potential for gusty gap winds... ...Guidance Evaluation/Preferences... Model and ensemble guidance is well clustered Friday into Saturday in a pattern with above normal predictability. A 12 UTC GFS/ECMWF/UKMET/Canadian blend seems to reasonably mitigate differences while providing good system detail. Predictability starts to decrease over the weekend due to uncertainties with retrogression and eventual weakening of a main upper ridge/closed high working over the Bering Sea. This affects downstream digging and undercutting of northern stream energy to the lee from the mainland to the Gulf of Alaska and interaction with northward rotating Pacific systems. Shifted the forecast in favor of the 12 UTC GFS/Canadian to best maintain the blocky upper ridge/closed high, but included input of the 12 UTC GEFS/ECMWF ensemble means given growing forecast spread. Blocky flow tends to persist within the slower envelope of model and ensemble forecasts. Additionally 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 stark trend to much colder temperatures for this forecast period for much of the state, with the brunt of the frigid air likely over the eastern Interior. 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 and undercutting an 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 still offer some timing/strength challenges, but seem likely to periodically focus enhanced winds/tighter pressure gradient supporting local gap winds later week through the weekend down through east-central portions of the Brooks Range/Interior/Alaska Range/SouthCentral and Southeast Alaska before working into the northern Gulf of Alaska. This northern stream upper low/trough energy remains set to undercut over Gulf waters, but offers uncertain potential to interact with southern stream Pacific system energies. It seems increasingly possible that in addition to remaining a protracted maritime wind/wave threat, there is growing support that energies/moisture lifting on the eastern periphery in cyclonic flow may lead to a renewed Southeast to SouthCentral snow threat early next week. 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