Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 758 PM EDT Wed Apr 16 2025 Valid 12Z Sun 20 Apr 2025 - 12Z Thu 24 Apr 2025 ...General Overview... The next organized storm system develops over the central/western Aleutians on Sunday and will likely track in the general direction of the Alaska Peninsula come Tuesday morning, bringing more rain/mountain snow and gusty winds. Ahead of this storm will likely be a building ridge axis from the Gulf to the Interior, while a strong Arctic surface high and polar easterlies continue from the Brooks Range northward. An upper trough is likely to become established over the Gulf by the middle of next week. ...Guidance/Predictability Assessment... The 12Z model guidance suite, along with the 18Z GFS, are in good synoptic scale agreement across the Alaska domain for the upcoming weekend. By Monday, the GFS becomes faster with the Bering Sea storm system, and this continues to be the case going forward to Monday/Tuesday, and then north of the model consensus by mid-week as the system emerges over the Gulf, so less GFS was used for the latter half of the forecast period. Model and ensemble spread is higher than normal across the North Pacific and Gulf for Wednesday and Thursday, with multiple adjustments to the forecast expected in the days ahead. The WPC forecast transitioned to about half ensemble means by midweek. ...Weather/Hazards Highlights... Attention turns to the Aleutians storm by Sunday and into early next week with southerly flow advecting moisture towards the terrain of the Alaska Peninsula, and eventually Kodiak Island and the Kenai Peninsula. This does not appear to meet hazardous level criteria for now, but this will continue to be monitored in the days ahead. Temperatures are expected to be near to above average across central and southern portions of the mainland, and below average across the Brooks Range and to the Arctic Coast where the Arctic high will have more of an influence on the weather. There will likely be strong polar easterlies in place across northern Alaska, and even though winds are not expected to reach hazardous criteria, periods of blowing snow are possible. 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