Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 656 PM EST Fri Feb 21 2025 Valid 12Z Tue Feb 25 2025 - 12Z Sat Mar 1 2025 ...General Overview... A weakening surface low is expected to be in place across the northern Gulf Tuesday, followed by a second low moving north towards northern portions of the southeast Panhandle through Wednesday evening. This will be accompanied by onshore flow and is expected to locally heavy precipitation there through mid-week. A much stronger storm system develops over the north Pacific and tracks south of the Aleutians through the end of the week, and eventually reaching the Alaska Peninsula by next Saturday while weakening. This will also increase chances for moderate to heavy precipitation near the southern coastal areas. Meanwhile, an upper ridge axis is expected to extend from western Canada into the Interior through most of the forecast period, with relatively mild conditions for central and southern Alaska, and continued cold north of the Brooks Range. ...Guidance Evaluation and Preferences... There were some rather large model differences as early as Tuesday across the eastern Gulf with the first two weaker low pressure systems, and the GFS and to a lesser extent the GEFS were at odds with the better clustered CMC/ECMWF/UKMET/ECENS guidance through Wednesday. Therefore, a non-GFS blend was used across the domain for Tuesday and Wednesday to account for this, although the GFS was more in line elsewhere across the state. The differences with the GFS were actually lower going into the end of the week with the stronger Pacific low and the ridge across Alaska, so the GFS was introduced into the blend for days 6-8. Greater overall model differences become apparent by next Saturday with additional shortwave energy and surface low development behind it, so ensemble means were increased to about half for the Friday to Saturday time period. ...Weather/Hazards Highlights... Most of the state should enjoy above normal temperatures for the end of February with highs generally in the 20s and 30s for most of the southern half of the state, and lower to mid 40s near the coast. The Brooks Range will serve as the general demarcation boundary for much colder air over the North Slope and to the Arctic Coast as a strong arctic high to the north of the state provides a steady supply of very cold conditions, with lows bottoming out in the -10s and -20s. In terms of precipitation, multiple rounds of coastal rain and mountain snow can be expected for the southeast Panhandle region, and another surge of moisture in association with the big Pacific low late in the week will likely result in 1-3 inches of rainfall for parts of the Kenai Peninsula, Kodiak Island, and near the Prince William Sound, and heavy snow for the higher elevations. Widespread gale to strong force winds are likely across the open waters of the Gulf and potentially reaching some of the coastal zones, so this would create hazardous boating conditions. 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