Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 650 PM EST Tue Jan 28 2025 Valid 12Z Sat Feb 01 2025 - 12Z Wed Feb 05 2025 ...Gusty gap winds possible across southeast Alaska this weekend... ...Overview... An initially amplified pattern is likely when the period begins Saturday with an upper low positioned over the northeast Pacific and an anomalously strong ridge building over the Mainland. This should promote a period of much warmer than average temperatures across most of the state. On the east side of the ridge, northerly gap winds may be a hazard for parts of the Panhandle region, particularly in favorable locations. Meanwhile, mean troughing will prevail into at least early week across the Aleutians and western Bering, though with a lot of uncertainty on individual shortwaves/surface lows rounding the base of the trough. Moist inflow east of this trough will increase precipitation chances across the Aleutians, Alaska Peninsula, and western Mainland into next weekend and early next week with some gusty winds. ...Guidance Evaluation and Preferences... Latest model guidance for today shows fairly good agreement on the overall large scale pattern described above, but plenty of uncertainty in the details. The greatest area of uncertainty lies with individual shortwaves and surface lows rounding the base of the mean troughing over the western Bering Sea, through these for the most part should not have any impact on the mainland. Downstream, there is disagreement in a shortwave into the mainland and how this may or may not temporarily erode the ridge. 12z GFS showed a much stronger shortwave than other pieces of guidance. Despite some degree of ridge erosion, ridging in some form over much of the mainland looks to stick around through at least the end of the period/Wednesday. The WPC forecast for today used a blend of the 12z deterministic guidance early in the period. By Day 6 and beyond, gradually increased the ensemble means to 60 percent of the blend by Day 8, along with a 40 percent combination of the GFS, ECMWF, and CMC. ...Weather/Hazards Highlights... Northerly winds in between the upper ridge over the Mainland and the upper low over the northeast Pacific may channel winds in favored gap areas of the Southeast this weekend, depending on the orientation and strength of the pressure gradient. At the same time, frontal systems and lows will be tracking across the northern Pacific/Aleutians/Bering Sea through the weekend, leading to precipitation spreading across the Aleutians and possibly into the Alaska Peninsula late week. Southerly gusty winds are possible in those areas as well near/along the associated cold fronts. Some precipitation is forecast to spread into the western Mainland next weekend and early next week, with some enhancement likely across the higher terrain of the Seward Peninsula and western Brooks Range. Some uncertainty on the exact amounts and potential impacts still. Temperatures may still be below average for the eastern Mainland as the period begins Saturday. These should quickly shift eastward through the weekend as upper ridging brings in warmer than average air. The greatest anomalies will be on the North Slope, where daytime highs could be 30+ degrees above normal. The exception to the warmth will be across Southeast Alaska where the upper low lingering just south of the Panhandle will keep temperatures below average into at least mid next week. Santorelli 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