Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 655 PM EST Thu Mar 10 2022 Valid 12Z Mon Mar 14 2022 - 12Z Fri Mar 18 2022 ...Overview... Potent energy is forecast to dive southward into the Alaska mainland early next week after rounding the northern side of an upper high over Siberia this weekend. This will create a southwest-northeast oriented upper trough across the state around midweek, with an embedded upper low perhaps closing off near or over the Alaska Peninsula. Farther south, an active storm track is expected for the northern Pacific influencing southern Alaska with upper-level shortwaves and surface low pressure systems, especially for the first half of the week before the flow becomes more dominated by the aforementioned upper trough, but with some interaction of the various energies and additional Gulf of Alaska lows. ...Guidance/Predictability Assessment... The easternmost upper low transitioning to a trough in a series of northern Pacific systems is forecast to support a surface low pressure system moving toward the Alaska Panhandle early in the workweek. This initial surface low has fairly good clustering among model guidance, though with perhaps the GEFS and GFS runs are slightly slow Monday-Tuesday compared to consensus of the other guidance. Later lows forced by this energy train and eventually the northern stream upper trough are not quite as agreeable with the details, led by some differences in the smaller scale shortwaves that may take until the short range to resolve, but also related to differences with the trough dropping into the mainland. For the mainland trough, model guidance has trended slightly weaker today compared to the previous forecast, but the westward extent of its reach remains in question. Most deterministic guidance from the 12Z model cycle showed a westward shift in the trough/embedded low compared to the ensemble means by Wednesday-Thursday. At this point it seems too early to tell if this is a consistent trend to follow or not, since the ensemble means remained east. The 12Z ECMWF mean that was not available in time of forecast creation did show a slight westward shift compared to the previous one, but not to the extent of the operational runs. By late in the period the ensemble means agree that the primary focus for low pressure should eventually gravitate to the northeastern Pacific/Gulf of Alaska due to the mainland upper trough. However, differences in the placement and strength of the surface lows remain notable, with a general idea of ensemble means farther north with the lows and operational models farther south. Thus the WPC forecast began with a multi-model deterministic blend early in the period, but as the period progressed phased in the GEFS/EC ensemble means, which were at least somewhat well clustered. Kept mainly the ECMWF in the blend in terms of the deterministicÂguidance as it may be the best proxy for the consensus and to keep some depth for some of those lows. This led to a middle ground solution with positions of the mainland trough/upper low and surface lows, somewhat favoring the ensemble means at this point pending future model cycles. ...Weather/Hazard Highlights... Much of the mainland should see dry conditions during the period, as precipitation is expected to focus along southern parts of Alaska given the northern Pacific storm track. The Panhandle in particular could see rounds of modest to enhanced totals beginning Monday given moist inflow and a series of low pressure systems. Some lighter precipitation is also possible farther west, from the Aleutians to Alaska Peninsula to Southcentral Alaska. Additionally, brisk winds are possible next week, with current forecasts indicating gusty winds in the Gulf/northeast Pacific with the initial low Monday-Tuesday and then breezy northerly winds over the Aleutians for later in the week. A transition to colder than average temperatures is forecast next week for much of Alaska with troughing aloft. This will particularly be true in terms of highs, which could be 10-30F below normal for mid-March. The North Slope will be the main area that can expect near to above normal temperatures. Meanwhile, the Panhandle should see below normal highs through the period and a mix of above and below normal lows. Tate No significant hazards are expected over Alaska during this forecast period. 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