Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 603 PM EST Sun Nov 10 2024 Valid 12Z Thu Nov 14 2024 - 12Z Mon Nov 18 2024 ***Bering Sea storm could bring gusty winds and increased snow to Southwest Alaska for the end of the week*** ...Overview... A generally cold and mainly dry weather pattern can be expected for most of the Interior and to the Arctic Coast as a large scale synoptic trough will likely be in place across the state. The main storm track will generally be near the Aleutians and southern Bering Sea, with a strong low pressure system headed towards the southwest mainland, and a secondary low forming over the northern Gulf by later in the forecast period. Coastal rain and mountain snow is looking more likely toward the end of next week and into next weekend with onshore flow associated with the incoming Gulf low pressure system late in the period. ...Guidance Evaluation/Preferences... The 12Z model guidance suite initially has some disagreement across the Bering Sea region on Thursday, both with latitudinal and intensity differences with the Bering Sea low headed for the southwest coast, and a trailing disturbance behind it near the western Aleutians. Both the UKMET and CMC offer a stronger storm compared to the weaker GFS/ECMWF solutions, so an intermediate solution regarding intensity and placement was used in the WPC forecast, and a little less weighting to the GFS given its differences across the remainder of the Bering Sea region through Friday. Looking ahead to next weekend, the guidance has trended into better agreement with a well defined triple point low developing over the northern Gulf, and then developing further going into Sunday before weakening next Monday. The guidance is also picking up on a new low pressure system tracking just south of the Aleutians by the Sunday/Monday time period, with the GFS weaker and more progressive, and the CMC slower. The ensemble means were gradually increased to about 50% of the forecast blend by next Monday. ...Weather/Hazards Highlights... The approach of the Bering Sea low towards the southwestern mainland will likely increase winds and raise the potential for some coastal flooding for the Bristol Bay region, with increased snowfall moving inland. Breezy conditions are also likely across much of the Interior above the influence of the surface temperature inversion as the storm system moves inland and weakens. The models have continued to indicate a triple point low forming as energy is transferred from the Bering Sea low, and focusing a plume of Pacific moisture over South-central and Southeast Alaska. This will likely result in some heavier precipitation in these regions, especially along the coastal terrain where a few inches of QPF is possible. Arctic high pressure north of the state will usher in winter-like temperatures for most of the forecast period, with highs struggling to get above zero for many areas across the northern and eastern Interior, and extending north across the Brooks Range. Overnight lows could reach the -20s in some of the more sheltered Interior locations. 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