Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 759 PM EDT Tue Oct 31 2023 Valid 12Z Sat Nov 04 2023 - 12Z Wed Nov 08 2023 ...Overview with Guidance Evaluation and Preferences... Relatively benign weather appears to be in store for mainland Alaska through the medium-range period as the Alaskan domain remains sandwiched between an omega block over the Arctic Ocean and a large-scale cyclonic circulation passing at some distance south of the Gulf of Alaska. Meanwhile, an upper low caught in between the aforementioned regime is forecast to linger near the west coast of Alaska but it is not expected to produce active weather. Much of the model uncertainty has been associated with the cyclone(s) south of the Gulf of Alaska for much of the forecast period. The ECMWF has been indicating a separate and stronger cyclone to head toward the coast of British Columbia late this weekend into early next week. However, the EC ensemble mean shows a slower progression of this cyclone, with the GFS and CMC indicate a single deep cyclone much farther offshore. The ECMWF solution is considered to be an outlier at this time but will be continued to be monitored in upcoming forecast cycles. By the middle of next week, ensemble means (GEFS, EC mean, and CMC mean) are in fairly good agreement to slide the upper low near the west coast of Alaska southeastward and merge with the large-scale cyclone south of the Gulf of Alaska. The merger and interactions appear to reinvigorate and expand the large-scale the cyclone offshore. Thus the WPC forecast for the Alaskan domain was based on a blend of the 12Z GFS/ECMWF/CMC early in the period with a lesser proportion from the deterministic models, especially the ECMWF, in favor of the consensus of the GEFS/CMC/EC ensemble means as the forecast period progressed. ...Weather and Hazards Highlights... Precipitation across the state should be generally light to moderate through the period, with the southern perimeter of the state expected to receive the highest amounts of precipitation. Portions of the Kodiak Island into Southcentral and parts of Southeast Alaska should see some enhanced totals from time to time but they are not likely to be very heavy. In terms of precipitation types, rain is expected in the lower elevations and some snow in the Alaska Range. Windy conditions can be expected across the Aleutians during the weekend with pattern that favors a tight pressure gradient. Temperatures will be gradually dropping closer to normal late week, but may remain slightly above average for most of the Mainland (except the Brooks Range) until early next week when the upper low goes more overhead, flipping highs to a few degrees below normal in many areas. Lows on average should stay near to above normal in most areas though. The North Slope is likely to stay above average with some milder onshore flow. Meanwhile Southeast Alaska and the Aleutians look to see temperatures generally within a few degrees of average. Kong No significant hazards are expected over Alaska during this forecast period. 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