Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 352 PM EST Sun Jan 12 2025 Valid 12Z Thu Jan 16 2025 - 12Z Mon Jan 20 2025 ...General Overview... Active weather will continue late this week into the weekend for portions of the southern Mainland and Southeast Alaska as a few low pressure systems merge with the main centroid of the system moving from south of the Aleutians into the Bering Sea. As the system grows in scale, moderate to heavy rainfall edges east across the AK Peninsula, south-central AK, and the northern AK Panhandle by the weekend. ...Model Guidance Assessment... The 12Z suite of model guidance remains in good agreement on the upper level pattern and surface features from late this week into the weekend, though there are the usual detail differences. The pressures, fronts, winds, and QPF were primarily based on a blend of the 12z deterministic guidance early on (GFS/ECMWF/CMC/UKMET) before a modest amount of the 00z ECMWF and 12z NAEFS means were used later on. Most of the other grids should be more 19z NBM based, as usual. ...Weather/Hazards Highlights... Heavy precipitation will spread across South-central and Southeast Alaska through the weekend as a broadening closed low expands eastward, shifting the atmospheric river from the Pacific slowly in that direction with time. Rain should linger across the Aleutians and southwest AK through the period. Above normal temperatures will make rain the main precipitation type in southwest AK, but wintry mixed precipitation and snow will be possible farther east and at elevation. Rain falling on top of snow could enhance snowmelt and lead to localized flooding concerns in some areas, such as Kodiak Island. The strong nature of the low will also likely produce strong gusty winds from the Aleutians to southwestern Alaska across the Bering Sea and Bering Strait. The Northern Slope should be breezy as well. Roth 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