000 FXUS63 KGRB 090501 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 1101 PM CST Wed Feb 8 2023 Updated aviation portion for 06Z TAF issuance .SHORT TERM...Tonight and Thursday Issued at 245 PM CST Wed Feb 8 2023 Mostly clear skies are expected this evening, which should allow temperatures to fall fairly quickly where there is still significant snow on the ground. Clouds will increase again after midnight and keep temperatures from falling much further later tonight. The computer models all forecast a negatively tilted 500mb trough to lift rapidly northeast from Tulsa at midnight to Milwaukee around midday Thursday and Lake Huron by Thursday evening. Strong upper diffluent flow combined with low level warm advection and Gulf moisture should produce a three or four hour period of moderate to heavy snow between 10am and 2pm with lighter snow a few hours before and after. 850mb temperatures are initially above freezing, but should drop due to evaporative cooling once precipitation begins, and cool even more due to strong vertical motion during the midday hours. So there may be some rain mixed in with the snow at the start but think the precipitation will be mostly snow. The snow will be wet and heavy and difficult to shovel and plow. .LONG TERM...Thursday Night Through Wednesday Issued at 245 PM CST Wed Feb 8 2023 Once Thursday`s system exits the region Thursday evening, a less active pattern with above normal temperatures is anticipated through this forecast period. Thursday night through Friday...As Thursday`s system continues to exit the region, lingering snow showers will prevail through Thursday evening. A couple tenths of additional slushy snowfall is possible through Thursday evening, mainly in east-central and far north-central WI. Some rain may still mix with the snow as it comes to an end in east-central WI, but there is still uncertainty with this as models vary on how quickly the colder air moves into the region from the northwest. Snow showers will continue in far north- central WI through Friday morning due to northwest winds generating lake-effect snow. Gusty northwest winds will gradually decrease throughout Thursday night and into early Friday morning. Do not anticipate major impacts from the gusty winds and snow, but cannot rule out some drifting snow in far north-central WI. Rest of the extended...A split flow will remain in place for the weekend and into next week resulting in little chances for precipitation. Saturday may be gusty due to a tightening pressure gradient from a clipper tracking north of the region. Models then indicate a weak shortwave may spark off some rain or snow showers on Monday, but there are timing and placement differences. Temperatures will also be above normal through the weekend and into early next week with high temperatures in the 30s each day. && .AVIATION...for 06Z TAF Issuance Issued at 1101 PM CST Wed Feb 8 2023 Good flying conditions are expected for most of the region still overnight, although some patchy fog has developed along the lakeshore which will affect MTW. Then attention turns to the approaching winter system from the south, which will bring IFR conditions for much of Thursday for areas roughly from Escanaba to Wisconsin Rapids and eastwards. The only change to the forecast for this system has been a slight shift southeast and a timing change of a couple hours. Those in the Fox Valley and lakeshore will likely still see a few inches of slushy accumulation through the day Thursday, especially for the southern Fox Valley and eastwards to the Lake Michigan shoreline. Snow will last most of Thursday but some improvement will already be likely towards the end of the TAF period Thursday evening. MVFR conditions will be north and west of the aforementioned line, with some lighter snow over the day Thursday. && .GRB WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory from 6 AM to 6 PM CST Thursday for WIZ022-037>040-045-048>050. && $$ SHORT TERM.....RDM LONG TERM......Kruk AVIATION.......Uhlmann