Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 755 PM EDT Tue Mar 29 2022 Valid 12Z Sat Apr 02 2022 - 12Z Wed Apr 06 2022 ...Overview... A mid-upper high to the northwest of Alaska should retreat by early next week, giving way to rounds of general upper troughing/lows across especially western and southern parts of the state. At the surface, low systems are expected to track across the northern Pacific/Gulf of Alaska while additional low pressure may linger near the southwestern mainland. This will promote a wet pattern for southern Alaska, particularly over the Panhandle, though amounts do not look to be terribly heavy. Meanwhile a reasonably tight surface pressure gradient with an arctic high and southern Alaska lows could lead to some moderate to strong winds over the North Slope, along with some breezy conditions possible along other low tracks as well. ...Guidance/Predictability Assessment... While model guidance all shows the retreat of the aforementioned upper high over the weekend and upper lows becoming favored near and over the state, there remain notable differences in the details of these features and the individual surface lows with a fairly active storm track near the Gulf. Deterministic models are somewhat agreeable that there should be surface low pressure in the Bering/hovering near the southwest mainland through early next week, which could stay separate from a couple of lows south of the state--one in the Gulf over the weekend, and one tracking across the Aleutians Saturday, south of of the Alaska Peninsula, Sunday and then into the Gulf Monday. The ensemble means on the other hand may be erroneously splitting the difference in these low's location, showing one low near the Alaska Peninsula. Thus, stuck with the operational models led by the 06/12Z GFS and 12Z ECMWF and their separate low features for the first half of the period. These deterministic models show some spread with exact location of the lows but well within reason for a medium range forecast. Then flow well west of the state over the Kamchatka/Bering Sea gets to be out of phase around Tuesday between the GFS and CMC runs versus the 12Z ECMWF, affecting a possible low over the Aleutians next week. The previous 00Z EC clustered better with the other models, so it seems the 12Z EC is an outlier by then, and leaned away from it. Added some ensemble mean influence by the latter part of the period too with the increasing operational model differences. Deterministic models show a potent surface low coming into the northern Pacific from the southwest by next Wednesday, which will be monitored in future forecasts as it could be impactful. ...Weather/Hazard Highlights... Precipitation is possible over southern parts of Alaska from the Aleutians and Alaska Peninsula east into Southcentral and the Panhandle this weekend into next week, given moist southerly flow ahead of low pressure systems. Precipitation amounts should vary from day to day and place to place. Some rain/snow amounts could be enhanced at times, but the heaviest totals through the period will be dependent on exact low tracks that are uncertain at this point. The current forecast indicates southern portions of the Panhandle may receive the most precipitation overall, with local enhancements elsewhere. Periods of gusty winds are also possible along low tracks, and the gradient south of Arctic high pressure may support a period of strong winds across the North Slope. Above normal temperatures should be most common over the southwestern half of the mainland, with greatest anomalies being for morning lows over far southwestern areas over the weekend. The northeastern half of the mainland should see a mix of above/below normal readings, with below normal temperatures most likely over the North Slope and central-northeast interior. The general transition of the mean pattern toward lower heights aloft should lead to a gradual cooling trend over some areas, in particular expanding the coverage of below normal highs. Expect the Panhandle to see below normal highs and near to above normal lows through the period. Tate Hazards: - High winds across portions of northern mainland Alaska, Fri-Mon, Apr 1-Apr 4. 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