Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 657 PM EST Sun Mar 3 2024 Valid 12Z Thu Mar 7 2024 - 12Z Mon Mar 11 2024 ...General Overview... An upper level trough and accompanying cold front is forecast to extend southward from the Arctic going into the end of the work week, resulting in a return to colder temperatures for much of the Mainland that will persist into next weekend. Meanwhile, a low pressure system system is forecast to track south of the Aleutians and into the northern Gulf by Friday, with increasing prospects for precipitation across the Southern Coast, Southeast Alaska, and adjacent mountain ranges. A deep surface low over the western/central Aleutians on Friday is expected to produce a triple point low that will likely reach the Gulf over the weekend, but may take a more southern track compared to the previous low. ...Guidance Evaluation and Preferences... The 12Z model guidance suite generally featured above average synoptic scale agreement, although still some uncertainty in the details of individual mesoscale systems, including a northward displacement with the CMC for the low over the Gulf region Thursday into Friday. The guidance initially agrees quite well with the second storm system over the Aleutians through early Friday, after which the GFS becomes more progressive. There is good model support for a triple point low forming as this low approaches the Gulf on Saturday, and this is also strongly supported by the latest machine learning (ML) guidance with a potentially strong low evolving. Looking ahead to next Monday, a third system may reach the southern Gulf in a continued active north Pacific flow pattern, with the ML guidance favoring a more southern solution here as well, in contrast to the GFS which has this low much closer to the southern coast. The WPC progs incorporated increasing proportions of the ensemble means into the blend through the Saturday to Monday time period, with a roughly 50/50 blend of the deterministic models and ensembles by Monday. Overall, this maintained good continuity with the previous WPC Alaska forecast. ...Weather/Hazards Highlights... Precipitation chances increase across Southeast Alaska through the period as a couple of surface lows and frontal systems affect the region. Multi-day totals of several inches of precipitation is possible, especially next weekend across the coastal mountain ranges where orographic forcing is maximized. Precipitation (rain and mountain snow) should extend back into the Southeast Coast/AK Peninsula and portions of the mainland under general unsettled flow/troughing, but with much less intensity. The Aleutians should stay wet and unsettled for much of the forecast period as several systems move through the region. In terms of temperatures, relatively mild conditions can be expected across most of the mainland through about Wednesday, with above normal temperatures across Western and interior Alaska. A cold front crossing western mainland Alaska will bring readings back down to below average levels by early March standards for the western half of the state, and the North Slope, by the end of the week and lasting into the weekend. Hamrick 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