Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 738 PM EDT Tue Oct 04 2022 Valid 12Z Sat Oct 08 2022 - 12Z Wed Oct 12 2022 ...Heavy precipitation threat for South-central to Southeastern Alaska through the weekend may return early-mid next week... ...Guidance/Predictability Assessment and Weather/Hazards Highlights... The 12 UTC ECMWF/UKMET/Canadian solutions seem best clustered over the weekend and a composite blend favoring these models seems to offer a good basis for the forecast. The 12 UTC GFS was also included in the blend with offering of a less amplified mainland to Gulf of Alaska upper trough that has some plausibility given progressive flow upstream. However, the 18 UTC GFS is trending somewhat more amplified. Regardless, expect a swath of precipitation and increased wind flow/cooling across the Interior and northern Alaska with system passage and a multi-day threat for heavy rains and terrain enhanced snows across south-central and southeastern Alaska given longer fetch moisture inflow with Gulf of Alaska system genesis under favorable upper support. Rain is probable for the Aleutians along with some renewed enhanced precipitation for the southwest/southern Interior Sunday into early next week. However, surface system timing and emphasis differences become more problematic next week in quite energetic flow. That said, model and ensemble solutions seem to favor a similar patern evolution aloft into mid-later next week and highlight development of an amplified trough from the Bering Sea through the Aleutians. There is a growing signal to monitor for the tapping of mid-latitude Pacific system energy/moisture that could fuel another threat for heavy precipitation back into south-central to southeastern Alaska at these longer time frames. The WPC medium range product suite derivation relied increaisngly on the most compatible GEFS/ECMWF ensemble means and manually applied adjustements to blend output to mitigate some system weakening inherent to the blending process, mainly for offshore surface lows given seemingly favorable upper support. Schichtel Hazards: - Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Fri-Sun, Oct 7-Oct 9. - High winds across portions of mainland Alaska, Fri, Oct 7. 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