Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 803 PM EDT Wed Jul 20 2022 Valid 12Z Mon Jul 25 2022 - 12Z Fri Jul 29 2022 ...Heavy rain possible across portions of coastal southern Alaska and the Southeast through Tuesday... ...Much below normal temperatures expected for parts of northern Mainland through midweek... ...General Overview... Multiple impulses of energy will eject out across the Aleutians and Gulf leading to heavy rain from the Kenai Peninsula to the Southeast as the upper level low weakens over the western half of the state. ...Guidance/Predictability Assessment... Overall, models are in agreement that the upper low weakens and that multiple impulses will track across the Aleutians/Gulf. These features will keep cooler temperatures across the northern part of the state while the southern coastal region and the Southeast will be wet for a few days. For several days now the GFS has been faster and further east with the surface features. The latest runs were hinting at being west/south of the rest of the cluster initially before returning to an eastward placement by mid/latter periods. This trend doesn't bolster confidence with it so its inclusion with the WPC blend was minimal early on and then omitted completely by the tail end of the forecast. The ECWMF has been persistent in depicting a stronger low that emerges from south of the Aleutians by the start of the week with a more amplified trough in place. Model spread in the timing and placement of the surface features increased with this cycle which decreased confidence on specifics. The WPC blend leaned heavier toward the ECWMF/EC means but also used the CMC/UKMET/GEFS means; with the means making up 50% of the blend by the end of the forecast. ...Sensible Weather... Temperatures, especially the overnight lows, are forecast to be much below normal across northern portions of the Mainland; ranging from the 30s to the low 50s. The daily maximums will mostly range from the 40s to 60s, however a few locations may actually reach the low 70s. There will be occasional breaks in the cloud cover, but most areas will be mostly cloudy to overcast. Much of the southern coastal areas and the Southeast will be in a prolonged wet period with multiple rounds of showers and thunderstorms. Periods of moderate to heavy rainfall is expected through Tuesday July 26th which may lead to areas that receive excessive rainfall and develop localized flooding concerns. During this time 3 to 7 inches of rainfall is forecast with isolated higher amounts possible. Campbell 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 - Heavy rain across portions of the Alaska Panhandle and mainland Alaska, Sun-Tue, Jul 24-Jul 26. - Much below normal temperatures across portions of mainland Alaska, Sat-Wed, Jul 23-Jul 27. 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