Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 657 PM EST Tue Nov 15 2022 Valid 12Z Sat Nov 19 2022 - 12Z Wed Nov 23 2022 ...Overview... An anomalously strong upper ridge and surface high over the mainland and Panhandle of Alaska in the short range period will persist through this weekend but gradually weaken with time. Temperatures by the start of the period on Saturday should start to moderate some from the short range, but still well above normal for this time of the year. As a result of the initial blocky ridge, the main storm track will be deflected to the south with low pressure systems tracking across the northern Pacific into the Gulf, which could affect southern coastal locations from the Aleutians to the Panhandle. The ridge looks to finally break and shift east as an upper low over eastern Russia sends troughing into the Bering Sea mid next week. ...Guidance/Predictability Assessment and Preferences... For the most part, model guidance remains agreeable with the overall pattern of a strong upper ridge initially over the Panhandle and mainland that should slowly weaken through the period. This good agreement for the synoptic pattern yields fair agreement in the general storm track areas around the ridge as well for at least the first few days of the period, but with less certainty on the exact details. Timing on a surface low near the Aleutians on Saturday shows a fair bit of uncertainty still on timing as it tracks into the Gulf next week. The 12z ECMWF is noticeably faster than the rest of the models on this feature and was not favored in the blend for today's forecast. The GFS (and CMC and UKMET) were slower and closer to the ensemble mean agreement. That is the main feature of note during the medium range period, but there is also plenty of shortwave uncertainty later in the period through the Bering Sea as well. With decent agreement, the WPC forecast utilized a general model blend for days 4 and 5. After this, the 12z GFS was favored more over any other deterministic solution along with increasing amounts of the ensemble means through day 8. ...Sensible Weather and Potential Hazards... With a southerly storm track, general unsettled conditions will persist across the southern coastal regions of Alaska with light to moderate precipitation from the Aleutians to the Alaska Peninsula. As the low moves into the Gulf and taps deeper moisture, precipitation should become more widespread to possibly heavy along the Southern Coast and northern Panhandle region this weekend and early next week. A front across the mainland may support some precipitation in spots, but mostly should be very light and scattered in nature. The upper ridge will support much above normal temperatures for much of the state, but especially across the North Slope. By Saturday however, temperatures should begin to moderate some as the ridge weakens, but still remaining modestly above normal through about Monday. Troughing from the Bering Sea should begin to bring temperatures across western and southwest Alaska/the Aleutians back to normal or below normal next Tuesday-Wednesday. Santorelli Hazards: - Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Sat-Tue, Nov 19-Nov 22. 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