700 FXUS63 KGRB 071203 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 603 AM CST Mon Jan 7 2019 Updated aviation portion for 12Z TAF issuance .SHORT TERM...Today...Tonight...and Tuesday Issued at 356 AM CST Mon Jan 7 2019 The snow will continue to change to rain from south to north this morning. Another 2 to 4 inches of snow should fall north of a Merrill to Marinette to Washington Island line with little or no additional snow south of a Kewaunee to Stevens Point line. The precipitation should end during the afternoon. Roads and sidewalks will likely be slippery for awhile even where the snow has changed to rain so will keep the winter weather advisory for a little while there. Highs today will rise into the middle 30s in the far north to low 40s in the south. CLoudy skies will hold temperatures up tonight. Lows will be mostly in the 20s. Jet energy moving across southern Wisconsin and upper Michigan Tuesday should produce some light snow across the Northwoods and across the southern most counties of the forecast area with a small accumulation possible. .LONG TERM...Tuesday Night Through Sunday Issued at 356 AM CST Mon Jan 7 2019 Forecast concerns generally revolve around light snow chances over the period. In general, a colder pattern will be developing across the region as upper flow turns to the northwest. Due to the ongoing winter storm, only cosmetic changes were made to the multi-model blend initialization. Tuesday night through Wednesday night...A potent shortwave will be dropping across northeast WI on Tuesday evening. With sharp cyclonic flow overhead and broad cyclonic flow in the lower levels, decent moisture up to 700mb may lead to scattered snow showers across much of the area, but perhaps a bit more numerous over far northeast WI. Think any snow shower activity will tail off at most areas except over the north-central WI snow belt overnight. Dont think will see much in the way of accumulations outside of this snow belt area, where maybe a half inch to an inch could fall. Better accumulations could occur on Wednesday and Wednesday night in the Vilas county snow belt as wind trajectories become more favorable for lake effect. Will increase snow chances and forecast accums in this area. Otherwise, partly to mostly cloudy skies should continue for much of this period. The airmass will be considerably colder than the one over the past few days, with highs on Wednesday in the upper teens to low 20s. Rest of the forecast...The lake effect machine should tail off on Thursday as Arctic high pressure and associated dry air builds into the region. Should also see more clearing take place with the incoming dry air. Any clearing should be brief, however, as models continue to indicate a clipper impacting the region with light snowfall on late Thursday night through Friday night. At this time, it looks like a long duration, light snow event for most areas, though some suggestions of lake enhancement near the Lake Michigan shoreline could make things more interesting. Though the light snow should diminish early next weekend, may not see some sun until Sunday. && .AVIATION...for 12Z TAF Issuance Issued at 603 AM CST Mon Jan 7 2019 IFR conditions expected today as snow changes to rain from south to north before ending this afternoon. Gusty southeast surface winds may produce cross winds on some runways, and there may be some low level wind shear with southeast winds around 55 knots at 2000 ft through midday. Several more inches of snow could fall between 6am and 10am in far northern Wisconsin with little or none further south. Pavement areas may be snow covered even where the snow has changed to rain. Mostly cloudy skies are expected tonight and Tuesday with MVFR or VFR conditions. Some light snow is possible Tuesday as an upper level disturbance moves across the area. && .GRB WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 8 AM CST this morning for WIZ022- 038>040-073-074. Winter Weather Advisory until 9 AM CST this morning for WIZ030- 031-035>037. Winter Weather Advisory until noon CST today for WIZ005-010- 018>020. Winter Storm Warning until noon CST today for WIZ011>013-021. && $$ SHORT TERM.....RDM LONG TERM......MPC AVIATION.......RDM