Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 711 PM EDT Fri Apr 29 2022 Valid 12Z Tue May 03 2022 - 12Z Sat May 07 2022 ...Guidance/Predictability Assessment... An active flow pattern is expected to evolve over the region through the extended period with a couple of storm systems likely to bring unsettled weather to portions of Alaska. The 12Z model guidance showed good agreement and clustering with the large scale pattern through much of next week, but seemed to vary more with timing and strength of individual systems, especially later next week. A general deterministic model blend (with more emphasis towards the better clustered ECMWF, GFS, and UKMET) sufficed as a starting point Tuesday and Wednesday. After this time, there is some disagreement in timing of a second system towards the Gulf later in the week, with the CMC noticeably faster than the ECMWF and GFS, although there is some north/south variance in the ECMWF and GFS as well. The GFS and ECMWF show good agreement with a deeper low dropping south along the west coast of Alaska mid-week, but also begin to diverge a little in terms of timing and location late week. Thus, a trend towards more of the ensemble means was used for days 6-8, though modest amounts of the ECMWF and GFS were maintained for some added system definition. ...Weather and Hazard Highlights... A low pressure system in the Gulf when the period begins on Tuesday will meander until about Wednesday before it weakens as it interacts/gets wrapped into a compact upper low dropping south across Western Alaska. Ample moisture ahead of the attendant cold front should direct towards the Panhandle and Southern Coast region with moderate to locally heavy rainfall possible Tuesday and into Wednesday. Moisture may linger, but precipitation should lessen in intensity mid to later next week as the low weakens, but some kind of upper troughing maintains over the Gulf. Meanwhile, a stationary boundary as well as the upper low along the West Coast should keep some scattered rain and snow showers across parts of southern Mainland Alaska and southwest Alaska as well. The next low into the Gulf next Friday into Saturday should stay south enough of the Aleutians to limit impacts, but an uptick in moisture for parts of the Southern Coast and Panhandle is once again possible by next weekend as the low drifts more into the Gulf. Temperatures across southern Alaska/the Panhandle and also the North Slope region should remain near or below normal through next week as systems move through. Across central and especially east-central Alaska, upper level ridging should keep daytime highs above normal, and combined with a remaining snow pack in the region, could lead to some flooding concerns across portions of the Yukon River Basin in eastern Alaska. Santorelli Hazards: -Flooding possible across portions of mainland Alaska, Mon-Fri, May 2-May 6. 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