Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 751 PM EDT Sun Oct 25 2020 Valid 12Z Thu Oct 29 2020 - 12Z Mon Nov 2 2020 ...Guidance/Predictability Assessment... The forecast period begins on Thursday with a nearly stationary surface low over the northern Gulf of Alaska, and a surface high holding strong over the Interior through next weekend. Meanwhile, an active weather pattern is likely for the Arctic Coast region with a couple of shortwave disturbances. With the exception of the faster 12Z CMC across the north Pacific with the storm system crossing south of the Aleutians, the deterministic guidance indicates reasonable mass field agreement for the end of the week, and then normal levels of model spread become apparent. By the end of the forecast period next weekend, a third system is forecast to approach the western Aleutians, with decent model agreement for a day 7 forecast regarding location and intensity of the surface low, with the 12Z ECMWF/ECENS a little faster than the model consensus. This is similar to the case with yesterday's forecast. The WPC fronts and pressures forecast was primarily derived from the 12Z GFS/ECWMF/EC mean, and with time increasing the weighting of EC mean along with some of the GEFS mean. Some previous WPC continuity was also incorporated into the forecast. ...Weather/Threats Highlights.. Periods of coastal rain and heavy mountain snow is expected across the southeast panhandle and portions of the southeastern Mainland through Friday, as the surface low over the northern Gulf produces onshore flow to the east of the low. Some snow showers and gusty northwest winds are likely across the Arctic Coast region as a couple of disturbances pass north of the region, particularly for the northwestern coast where some heavier snow will be possible. Little in the way of snow is expected for the Interior as high pressure will govern the overall weather pattern. The coldest temperatures are expected to be across the east-central portion of the state, where a strong low level temperature inversion will likely develop for valley locations, especially for the latter half of the forecast period. Depending on the track of the Aleutian storm system next weekend, strong winds and rough seas may materialize across this region, along with potentially heavy precipitation. Hamrick Additional 3-7 Day Hazard information can be found on the WPC medium range hazards 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