Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 355 PM EDT Thu Sep 5 2019 Valid 12Z Mon Sep 9 2019 - 12Z Fri Sep 13 2019 The forecast period begins on Monday with a broad trough over the Bering Sea and Aleutians, and a Rex block over western Canada with an upper level high over the Northwest Territories and a broad low over British Columbia. By midweek, the Bering Sea trough emerges as a low over the Gulf of Alaska, and a more powerful low pressure system emerges over the Bering Sea that lingers through the end of the week. The 00Z ECMWF was faster than the model consensus with both of these low pressure systems, and also well displaced from the EC mean. There was better agreement among the operational 00Z CMC, 12Z GFS, and the ensemble means, so a blend of those solutions served as a good starting point in the forecast process, along with less of the 00Z ECMWF. In terms of sensible weather, this equates to a rather active weather pattern for the maritime regions and coastal areas of the state, especially the Aleutians and the southern coast of Alaska. Increased moisture advection north of the Gulf low is expected to produce moderate to locally heavy rainfall from King Salmon to the southern Yukon border, including the Anchorage area. Gale force winds are likely across parts of the Aleutians and especially over the Bering sea for the middle to end of the week in association with the big surface low. Temperatures are expected to be mainly in the mid 50s to upper 60s for highs, and mid 30s to near 50 degrees for overnight lows. Hamrick -------------- Hazards: - Heavy rain across portions of mainland Alaska, Wed-Thu, Sep 11-Sep 12. Additional 3-7 Day Hazard information can be found on the WPC medium range hazards 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