Alaska Extended Forecast Discussion...UPDATED National Weather Service College Park MD 623 PM EDT Sun Jul 6 2025 Valid 12Z Thu 10 Jul 2025 - 12Z Mon 14 Jul 2025 ...Synoptic Overview... Late this week, a strong Arctic trough will swing across the northern half of Alaska while a couple of upper lows track along the Aleutians and into the Gulf. By the weekend, an upper level ridge is expected to nudge its way into northwestern portions of the state and the Arctic trough should lift to the northeast. Below normal temperatures are expected under the trough, but temperatures should rebound to near normal as the upper ridge moves in. Another upper low will develop in the Bering and move across the Aleutians and into the Gulf over the weekend and into early next week. At the surface, a series of low pressure systems will track along the southern coast into the Gulf, which will create daily precipitation chances for the southern half of the state. ...Guidance Evaluation and Preferences... There is surprisingly good agreement among the 12Z model runs from the GFS/CMC/ECMWF/UKMET and their respective ensemble means. However, run-to-run consistency has been lacking as there have been some relatively large pattern changes since 00Z. The GFS and CMC have been showing slightly better run-to-run consistency than the ECMWF. The 00Z ECMWF solution diverged significantly from the general consensus late in the period, bringing a very deep upper Arctic low towards the state. No other model solutions had this low as deep or south, making this an unlikely solution. By 12Z, the ECMWF trended towards the consensus, which was to build a ridge over northwestern Alaska and keep the Arctic low far to the northeast of the state. Even though 12Z model agreement is good, there is relatively low confidence on the upper level pattern across the north late in the period as details regarding the ridge and Arctic low placement and strength still seem uncertain. WPC's forecast was composed of a near even blend of the deterministic GFS/CMC/ECMWF/UKMET for July 10-11, resulting in a middle of the road solution that represents the pattern well. For July 12-14, ensemble means from the GEFS/CMCE/ECENS were added in increasing amounts and the UKMET was taken out (not available this far out). Contributions from the GFS/CMC/ECMWF were maintained through the end of the forecast period to retain details of individual systems. ...Weather/Hazards Highlights... An Arctic front will sink south across the northern half of Alaska this week, resulting in well below average temperatures for the North Slope and much of the Interior. Temperatures on Thursday and Friday are forecast to be 10-20 degrees below average in some areas. High temperatures will likely only reach the 40s and lower 50s while lows drop to near or just below freezing. Temperatures will be cold enough to support chances for snow showers in eastern portions of the Brooks Range late this week. Temperatures should rebound to near normal by the weekend, and northwestern Alaska may see temperatures rise to slightly above average early next week if the upper ridge builds overhead. Slightly below average temperatures are also expected for Southeast Alaska due to persistent cloud cover and precipitation chances from lows tracking into the Gulf. Daily precipitation chances will exist from Kodiak Island and the Kenai Peninsula down through Southeast Alaska, and there will be potential for locally heavy rainfall, especially Thursday and Friday. Precipitation amounts should trend lower over the weekend and early next week as the Pacific low track shifts to the south, but troughing along the coast will continue chances for at least light showers. Dolan 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