Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 654 PM EST Sat Feb 1 2025 Valid 12Z Wed Feb 5 2025 - 12Z Sun Feb 9 2025 ...Synoptic Overview... The main theme for the middle of the week into next weekend will be a negative EPO pattern featured by a strong mid-upper level ridge axis extending north from the Gulf and across the mainland. This should initially be a closed upper high just south of the Alaska Peninsula on Wednesday and this slowly sinks to the south through the end of the week, with the core of the ridge likely rebuilding towards the southern mainland by next Sunday. Meanwhile, shortwave energy and accompanying surface lows are expected to track around the western periphery of that ridge and cross the central/western Aleutians into the Bering Sea. This synoptic set-up will tend to maintain above normal temperatures and mostly dry conditions across the majority of the state through next weekend. ...Guidance Evaluation and Preferences... The 12Z model guidance agrees well on most facets of the forecast to begin the period Wednesday, with the best agreement on the strength and position of the main upper ridge across the state. The region with greatest uncertainty mid-week is across the southwestern portion of the domain to include the Aleutians and the Bering Sea where the main storm track will be. The GFS is considerably faster bringing a storm system northward across the Aleutians, and also has a stronger low that develops over the eastern Gulf by Thursday, which does not have much support from the overall model consensus, so therefore the 12Z GFS was weighted less than the CMC/ECMWF solutions. There are also differences with arctic shortwave energy crossing the northern periphery of the upper ridge, with the ECMWF/ECENS serving as middle ground solutions between the slower GFS and faster CMC. By next weekend, there is still good overall model support for the ridge axis extending north across the mainland, although the GFS is displaced a little to the southeast with the axis compared to the consensus. Much greater uncertainty resides across the western Bering and into Siberia however. The ensemble means were increased to about 40-60% by next weekend. ...Weather/Hazards Highlights... The weather is forecast to be relatively pleasant for this time of year with the upper high/ridge and surface high governing the overall weather pattern. The southern half of the state is expected to be mainly on the dry side and offshore flow along the southern coastal areas should keep precipitation coverage greatly reduced. There will likely be an increase in heavier showers across portions of the Alaska Peninsula and eastern Aleutians by next weekend as the storm track gradually moves farther east. There should be some light snow or mixed precipitation (closer to the Seward Peninsula) across portions of northwestern Alaska through the middle to end of the week. Temperatures are expected to be pleasant by early February standards across the mainland with highs running about 15-25 degrees above seasonal averages. A modest cool-down is probable going into the end of the week in the wake of the arctic shortwave passage, but still a little above normal in most cases. There may be some Interior valleys that have surface inversions that don't mix out, and those areas would still remain rather cold. Another gradual warm-up is expected by next Sunday as a warm front lifts northward across the region. The Southeast Panhandle region should also be colder than average most days with an arctic surface high situated over southwestern Canada. 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