822 FXUS63 KGRB 200451 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 1151 PM CDT Sun Apr 19 2020 Updated aviation portion for 06Z TAF issuance .SHORT TERM...Tonight and Monday Issued at 423 PM CDT Sun Apr 19 2020 The main focus for this forecast period is the potential for showers and thunderstorms on Monday. This evening through tonight...Generally, quiet conditions are expected for this evening and tonight as a high pressure system resides near the forecast area. The gusty west/northwest winds will decrease later this evening along with clearing skies. Below normal low temperatures are expected overnight. Clouds will begin to increase over north-central Wisconsin towards daybreak Monday as a weak boundary marches into the Upper Mississippi Valley from Canada. Monday...As the weak boundary nears the forecast area Monday morning, surface winds will turn to the west and increase. Breezy conditions are then expected for Monday afternoon with gusts to 25 to 35 mph. In addition to the higher winds, there is potential for a few sprinkles to slide across the area Monday morning along this boundary. This weak boundary is associated with a surface low pressure system located in Manitoba. Also attached to this low is a cold front that will sweep across the area Monday afternoon. As this cold front appears have a bit more to work with (steep lapse rates and some WAA), guidance shows a line of showers and isolated non- severe thunderstorms developing along the front and moving from northwest to southeast across the forecast area. There are timing differences with the weak boundary and the cold front moving across the area. The general time frame for the showers and isolated thunderstorms, associated with the cold front, is from 3 PM through the beginning of the extended forecast, with the highest chance for thunderstorms across central and east-central Wisconsin. .LONG TERM...Monday Night Through Sunday Issued at 423 PM CDT Sun Apr 19 2020 Showers will continue Monday evening as a cold front tracks through the western Great Lakes region. Rain may changeover to snow across north-central Wisconsin as colder air filters into the region, with only a dusting of snow expected at most. Some rumbles of thunder are possible ahead of the front during the evening hours. High pressure will then build in behind the departing front, with dry weather expected late Monday night into Tuesday. A weak low pressure system will then track across the Great Lakes Tuesday night into Wednesday, settling just to the south of the area Wednesday night and Thursday. This low will bring the chance for light showers at times across the area through this time period. Models become unclear from Friday into next weekend as a low pressure system gets close to the region and depending on the model it could be dry or there could be showers at times, particularly Friday and Friday night as the ECMWF and Canadian both bring a swath of rain through the region as a mid level trough tracks through. Given the forecast models this far out are not very consistent among themselves or from run to run confidence in this portion of the forecast is low. Temperatures will generally be around or a bit below normal through the week and into next weekend. && .AVIATION...for 06Z TAF Issuance Issued at 1151 PM CDT Sun Apr 19 2020 VFR conditions will continue overnight. Light south surface winds and southwest winds around 45 knots at 2000 ft could create low level wind shear late tonight north of a Rhinelander to Iron Mountain line. An approaching cold front will bring increasing clouds Monday, with scattered showers and thunderstorms in the afternoon. MVFR conditions are possible in northcentral Wisconsin, and with any shower or thunderstorm activity everywhere else. The cold front will exit the area Monday evening with clearing skies overnight. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....Hykin LONG TERM......Kurimski AVIATION.......RDM