Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 753 PM EDT Wed Jun 26 2024 Valid 12Z Sun Jun 30 2024 - 12Z Thu Jul 04 2024 ...Overview and Guidance Evaluation/Preferences... The ensemble means from the GEFS, EC, and CMC remain in good to excellent agreement on the evolution of the upper-air pattern across Alaska through the medium-range period. In this Rex Block configuration, an upper ridge will have a tendency to close off across the northern half of Alaska while an initially deep Bering Sea low weakens and slides under the ridge across the Gulf of Alaska through the middle of next week. The models have generally trended slower with the eastward motion of this low since yesterday. The deterministic solutions are even slower than the ensemble means. The WPC medium-range grids for Alaska was based on a general model compromise of 40% from the 12Z GFS and GEFS, 40% from the 00Z EC means and 12Z ECMWF, and 20% from the 12Z CMC and CMC mean. ...Weather/Hazards Highlights... This pattern will favor the Aleutians and AK Peninsula to be rainy, as the lingering Bering Sea cyclone gradually slides across the Aleutians reaching into the Gulf of Alaska by early next week. The double-barrel system will allow for modest rainfall in its vicinity. Winds should generally peak in the 30 kt (35 mph) range at times across the Arctic Coast and coastal areas. The terrain in south-central and northern AK are expected to have the best chance of showers and thunderstorms. There is the possibility of dry lightning strikes during the afternoons and evenings which would increase the risk for fire weather concerns given the dry fuels across the region. Ridging across the Mainland will maintain warm to hot temperatures. Afternoon maximums should lie the 80-90F range for the most part across the eastern interior sections. Highs mostly in the 60s and 70s are expected across lower elevations of south-central AK, with mainly 50s and 60s in most coastal areas, 50s and 40s across the North Slope, and mid to upper 40s in the Aleutians. Higher elevations in the terrain across south-central and southeast AK should fall below freezing overnight. The North Slope will be cool overnight with lows in the 30s, while highs will approach 60 degrees not too far inland from the shore, and perhaps to near 80 degrees farther inland over the central portion of the North Slope on Saturday. These temperatures would qualify for Hazardous Heat. The ongoing computer network issues have continued to prevent the creation of the Hazards map again today. Thereafter, a surface high pressure system gradually sliding from west to east off the northern coastline of Alaska will funnel colder air from the Arctic Ocean into the North Slope. Kong/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