Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 628 PM EDT Sat Jul 20 2024 Valid 12Z Wed Jul 24 2024 - 12Z Sun Jul 28 2024 ...Hazardous heat possible for parts of Interior Alaska into mid next week with increasing heavy rain threat late week... ...Overview... A strong upper ridge over the mainland as the period begins Wednesday will continue to promote well above normal temperatures for much of interior and northern Alaska through about mid next week. South of the ridge, a deep upper low will bring a period of moderate to locally heavy rains to parts of the Panhandle before it shifts inland on Wednesday. Another deep upper low in the Bering will shift eastward with time bringing heavy rainfall and significantly cooler temperatures into parts of the western to central/southern Mainland by next weekend. ...Guidance Evaluation/Preferences... The latest guidance continues to have a good handle on the overall synoptic pattern for the first half of the period as the upper low in the Bering lifts northeastward, but there are some mainly minor timing and detail differences that will take time to resolve. Another strong trough will drop southward from eastern Russia late week, and the models continue to show a lot of uncertainty on how this interacts with the Bering low. The better consensus (including AI/ML guidance) suggests this system should push the Bering low more south and east eventually resulting in some sort of triple point redevelopment in the Gulf. The GFS aligns with this general track, but was notably faster than the ECMWF. The CMC is stronger and faster with the northern trough and thus pushes the Bering low more eastward into northern Alaska. The WPC blend for today used a general operational model blend the first half of the period, but with greater weighting towards the ECMWF. Late in the period, leaned heavily on the ensemble means, with some operational ECMWF to help add some detail where feasible. ...Weather/Hazards Highlights... Rain, locally heavy, will be ongoing across the Panhandle region on Wednesday as an initial surface low pressure system moves through. The Bering Sea low will initially spread rain west to east across the Aleutians through about mid week, but as the cold front reaches the West Coast around Thursday or Friday next week, the threat for more widespread rains progressing steadily eastward with time increases across the Mainland into next weekend. Some of the rainfall could be heavy in spots, especially along/near the favored terrain and the southern coast as another surface low develops in the Gulf. Gusty winds may accompany this system, depending on exact strength, but should remain below hazards thresholds. Well above normal temperatures will continue through Wednesday, 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, with an increased wildfire threat as well. The ridge breaks down by Thursday and the next cold front will usher in cooler temperatures. By next Friday, much of Western and Central/Northern Alaska could be 10 to 20 degrees below normal lasting through the weekend. The exception to the heat will be across 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