Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 649 PM EDT Sun Mar 19 2023 Valid 12Z Thu Mar 23 2023 - 12Z Mon Mar 27 2023 ...Overview/Guidance Evaluation/Predictability Assessment... A broad upper trough will be situated over the Bering Sea for the middle of the week, and shortwave energy pivoting around the southern periphery of this trough will induce a new surface low just south of the Alaska Peninsula and Kodiak Island that will become the next event to make weather headlines for southern Alaska going into Thursday. This low may be on the order of 980 mb Wednesday night before drifting southeast through the end of the week and steadily weakening. A second low may follow quickly behind this one on Friday across the northern Gulf, but should be weaker. Looking ahead to next weekend, another well organized low pressure system will likely approach the western Bering and eastern Siberia as an upper level trough becomes amplified over this region, and a downstream upper ridge will likely be in place across eastern mainland Alaska and western Canada. The model guidance initially has a good overall depiction of the synoptic scale pattern, and the latest CMC has come into better agreement with the low evolution over the Gulf and also the Bering, so a multi-deterministic model blend sufficed as a starting point in the forecast process for Thursday and Friday. The GFS begins to differ significantly by late Saturday and beyond with a stronger surface/upper high over western Alaska and the eastern Aleutians, and a slower arrival of the next Bering Sea storm and also weaker, so it was weighted less for Saturday through Monday. The ECENS accounted for nearly half of the model blend by Monday and this also had support from the operational CMC and ECMWF. ...Weather/Hazard Highlights... Coastal rain and mountain snow will likely be ongoing from the northern Gulf low Wednesday night and into Thursday, although the heaviest precipitation is likely to occur on Wednesday. Moist onshore flow from the Kenai Peninsula to the southeast Panhandle should continue to keep rain/snow showers around through Thursday night for most of these areas. Strong winds are also possible for these coastal areas early on Thursday, mainly for the Kenai Peninsula and Kodiak Island where the pressure gradient will be tightest. Winds and precipitation could make a return to western portions of the state and the Aleutians depending on the eventual track of the next low pressure system entering the Bering late in the forecast period. In terms of temperatures, expect readings to generally be running 10 to 20 degrees above late March averages for central and northern portions of the state for the end of the week. A return to colder weather is appearing likely by late Friday across much of the mainland, and this continues into Saturday. If the next Bering Sea storm system generates enough southerly flow ahead of it, temperatures may return to above average levels once again across much of central and western portions of the state by Sunday. 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