Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 430 PM EDT Sun Sep 22 2019 Valid 12Z Thu Sep 26 2019 - 12Z Mon Sep 30 2019 An increasingly amplified upper-level pattern is forecast to dominate much of Alaska and the Bering Sea during the medium range period. A dissipating occluded systems will spread some rain down the Alaska Panhandle, with snow tapering off over the inland sections of southern Alaska on Thursday. Model guidance is in excellent agreement that a significant upper-level ridge will build northward toward southern Alaska for the rest of the week. This will allow a conduit of moisture to spread northward from a cut-off low in the central Pacific into southwestern Alaska later this week, possibly continuing into early next week. Global models continue to show run-to-run variability on how fast the cut-off low will move toward southwestern Alaska, leading to uncertainty with respect to the timing of the precipitation. The ECMWF has been on the fast side, while the latest 12Z run shows an even faster arrival time. Apt to lean toward the 00Z EC mean to handle the uncertainty. Therefore the WPC grids for Alaska were derived based on a consensus of the 00Z ECMWF, 00Z EC mean, 06Z GEFS mean, and 12Z GFS, with more weights given to the 00Z EC mean. Precipitation should not be excessively heavy at a particular instance but periods of rain can be expected to persist late this week into the weekend across southwestern Alaska. Nevertheless, storm total rainfall amounts could exceed 2 inches by the weekend. Kong 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