Alaska Extended Forecast Discussion...UPDATED National Weather Service College Park MD 528 PM EDT Tue Jul 8 2025 Valid 12Z Sat 12 Jul 2025 - 12Z Wed 16 Jul 2025 ...Heat forecast to build across portions of interior and northern Alaska this period while it stays wet in the south... ...Synoptic Overview... In general, upper level troughing persists in the Bering Sea while ridging waxes and wanes across northern and central AK and ridging marches eastward across Asia. Undercutting this blocking flow in the northern stream is a fairly zonal pattern from the Aleutians into the northeast Pacific/Gulf of AK. ...Guidance Evaluation and Preferences... Overall, there is reasonable model agreement, but the devil remains in the details, especially in about a week in the Aleutians where the GFS/ECMWF bring a fairly strong low nearby. Uncertainty with the warm core ridge in AK is seen later on as the guidance isn't sure what to do with a closed low retrograding across portions of the Bering -- allow it to become absorbed by the low to the south or let it retrograde into Siberia, and then come back towards western AK, which would erode the ridge. To deal with the uncertainties in the forecast, an even blend of the deterministic 12z runs of the GFS/CMC/ECMWF/UKMET was used early on before using up to 40% of the 12z NAEFS/00z ECMWF ensemble mean solutions later on ...Weather/Hazards Highlights... A warm core moving into northern and interior AK from north of Siberia is expected to lead to a period of heat that initially builds across interior AK from the 11th to the 14th, bringing highs into the 80s, but more uncommonly brings 70s and possibly 80s to the North Slope on the 14th. Uncertainties with the warm core ridge strength later on keeps a confident answer elusive, but hazardous heat areas were added to these areas. To the south, the series of lows moving into the Gulf will bring persistent rain chances across southernmost AK, with rain on the 11th in the Panhandle and then another batch of potentially heavy rainfall on the 14th and 15th -- heavy rain hazards exist across southeast AK and the AK Panhandle. With time, as ridging to the north erodes, the rainfall footprint and rain chances spread northward into central AK and into the Brooks Range, ending the interior and northern heat. The 12z Canadian shows heavy rain across the eastern interior later on, which will be watched in case better guidance agreement emerges on this possibility on later days. 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