Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 637 PM EDT Thu Jul 18 2024 Valid 12Z Mon Jul 22 2024 - 12Z Fri Jul 26 2024 ...Hazardous heat possible for parts of Interior Alaska early next week... ...Overview... A strong upper ridge over the mainland as the period begins Monday will promote well above normal temperatures for much of interior and northern Alaska through about mid next week, bringing some of the hottest temperatures of season thus far. A pair of deep upper lows over the Bering Sea and south of the Gulf will be slow to progress eastward within a fairly blocky early week pattern. Precipitation will be possible across parts of the Panhandle region, some locally heavy in nature, but generally not a heavy rainfall threat as the Gulf low slides into western Canada. As the ridge erodes over the Mainland by mid-week, the Bering low will shift inland bringing an increase in precipitation and much cooler temperatures. ...Guidance Evaluation/Preferences... The latest guidance continues to have a good handle on the overall synoptic pattern, and a general operational model compromise worked well for the day 4-5/Monday-Tuesday time frame. After this, there are some differences in placement/speed of the upper low as it moves through the Bering Sea. The UKMET was fast with it by Wednesday and was dropped from the forecast blend for today at this point. By later in the week, the ECMWF is much stronger with higher latitude energy that drops towards the domain, which helps to pull the Bering energy more northward and faster into the Mainland than the consensus. The GFS was noticeably slower as well with this. Favored a middle ground solution close to the ensemble means for the second half of the period, with smaller inclusions of the operational GFS, ECMWF, and CMC to help add details where feasible. ...Weather/Hazards Highlights... The surface low pressure system lifting towards the Panhandle region will bring some wet and unsettled weather to the region around Wednesday to Thursday next week. Locally heavy rainfall is possible in some locations, but generally this precipitation should remain below hazards thresholds. The Bering Sea low will spread rainfall east with time across the Aleutians and eventually into much of the Mainland later next week, with some enhancement of precipitation near favorable mountain ranges. This system may also produce some brisk winds on the backside across the Aleutians, but with speeds not likely to pose a significant hazard. Well above normal temperatures will be in place by Monday, with parts of the Mainland/Interior seeing some of the hottest temperatures of the season so far, bringing daytime highs into the 80s to near 90 degrees. These temperatures should stick around until around Wednesday before the ridge breaks down and shortwave energy ushers in cooler temperatures. By next Friday, much of Western and Central/Northern Alaska could be 10 to 20 degrees below normal. The exception to the heat will be across parts of the Southcentral to Southeast Alaska, where temperatures may be near or below normal for much of next week. Santorelli 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