Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 644 PM EDT Tue Apr 29 2025 Valid 12Z Sat 03 May 2025 - 12Z Wed 07 May 2025 ...General Overview... Unsettled weather conditions from the Alaska Peninsula to the southeast Panhandle courtesy of multiple low pressure systems and moist onshore flow from the Gulf. Aloft, a broad upper low is expected to be in place across the Bering for the end of the week, and then pivoting to the Gulf by Sunday and into early next week. Meanwhile, the Arctic surface high will continue to be strong and result in sustained polar easterlies north of the Brooks Range, and below average temperatures in many cases. ...Guidance/Predictability Assessment... Overall, the large scale pattern remains in good agreement amongst the deterministic and ensemble means through at least day 6 for the Bering Sea and points east. Both global and ensemble solutions lock in on a mean trough and surface low to track south of the Aleutians across the northern Gulf of Alaska through the end of the extended period with typical model differences by day 8. The low/trough feature exiting Siberia into the Bering Sea during days 7 and 8 continues to have a moderate degree of spread which lowers confidence on timing and strength of the next front to approach the region. The CMC is not as strong of an outlier as it was during the previous forecast period. In fact the latest version of the ECMWF and the GFS have trended toward that solution. To maintain some continuity, the forecast was initialized with a blend of the 12Z CMC/GFS/ECMWF/UKMET with slight emphasis toward the ECMWF and GFS. The ECMWF ensemble and GEFS means were introduced by day 5 and increased to nearly 50 percent of the weighting by day 8 to account for the noise with the Bering Sea system. ...Weather/Hazards Highlights... Late season heavy rainfall is still expected from eastern portions of the Alaska Peninsula to the Prince William Sound region for the end of the week. Precipitation intensity will decrease going into Friday as the low weakens. Wet and unsettled conditions will persist for the southern coast and the Panhandle. Periods of rain and mountain snow are expected as another storm system over the Gulf next weekend,but currently not expected to reach hazardous levels with that event. A quasi-stationary frontal boundary draped across the Interior for most of the forecast period will separate a mild and spring-like airmass across south-central Alaska, from a much colder and polar-like airmass from the Brooks Range northward. Temperatures are generally expected to be below average with the Arctic surface high continuing to govern the overall weather pattern. Campbell/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