Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
906 FXUS63 KMKX 290455 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 1155 PM CDT Mon Sep 28 2026 .KEY MESSAGES... - Periods of rain, heavy at times, will spread into southern Wisconsin Tuesday night and persist through Thursday. Expect a few rumbles of thunder as well. - Temperatures will be a few degrees above normal through Thursday, cooling down Friday through the weekend. && .SHORT TERM... Issued 1155 PM CDT Mon Sep 28 2026 Overnight through Thursday: We could see some patchy ground fog in the usual low spots again overnight due to clear skies and light winds. The visibilities at Kenosha and Sheboygan airports are bouncing around already. The surface high will start to shift east today (Tuesday) as a trough approaches from the northern Plains. Look for southerly winds to develop by early afternoon. This will usher slightly warmer air into southern WI this afternoon, but the main warm front will arrive this evening. The initial vorticity advection into southern WI this afternoon will run into dry air, but eventually the deeper moisture will arrive around midnight or a little later to bring a period of showers. There could be a few rumbles of thunder with this due to 925-850mb warm air advection and steeper mid level lapse rates. By Wednesday morning, the upper and lower jets will take on more of a west-east flow with the axis directly over southern WI. The latest GFS and NAM have trended southward over the past 24 hrs and now line it up directly overhead. WPC has our area in a slight risk for excessive rainfall Wed-Wed nt and this seems reasonable. Precipitable water values will be between 1.5 and 2 inches which is very high for this time of year (98th percentile). The rain Wed into Thu looks like it will have intermittent periods of higher rainfall rates. The short term ensembles (REFS, HREF) are showing a less than 10 percent chance for greater than 2 inches in a 24 hour period. This is due to the overall lack of convection. Timing of the more robust blobs of rain will have to wait for the event to begin. Similarly, the surface front needs to wait for a northern stream upper trough to push it south of southern WI. This could happen as early as Thursday afternoon or as late as Friday morning. Cronce && .LONG TERM... Issued 1155 PM CDT Mon Sep 28 2026 Friday through Monday: Breezy northerly winds will develop Friday in the wake of the cold front. The wind speeds will depend on the amplitude of the associated upper trough. Then high pressure will slide across the Great Lakes from Friday night through Saturday afternoon. Another upper trough will swing across Lake Superior Saturday night, but it looks like any rain will miss southern WI at this time. High pressure will return Sunday through Tuesday. Highs will be in the lower to mid 60s, with lows in the 40s. Cronce && .AVIATION... Issued 1155 PM CDT Mon Sep 28 2026 Southerly winds will then develop today (Tuesday) a low pressure approaches from the Northern Plains. Mostly clear skies early tomorrow should give way to increasing mid and high level clouds from the west by afternoon. Look for rain to start moving in tonight. Periods of rain (and low ceilings) will persist through Thursday. Cronce && .MARINE... Issued 1155 PM CDT Mon Sep 28 2026 The center of high pressure will shift over Lake Huron Tuesday. Look for areas of fog, dense possible, over the northern quarter of Lake Michigan overnight, but expect it to diminish by mid morning. Southerly winds will develop by early afternoon and continue into Thursday as a low pressure trough approaches from the northern Plains. Wind gusts to 30 knots are possible Wednesday afternoon along with building waves, particularly across central and northern portions of the lake. Expect northerly winds in the wake of the trough Thursday night into Friday. Strong high pressure will overspread the Great Lakes Friday night. A fast-moving trough should cross Lake Superior early Sunday but the amplitude is still uncertain, which would affect the wind speed. Cronce && .MKX WATCHES/WARNINGS/ADVISORIES... WI...None. LM...None. && $$ Visit us at weather.gov/milwaukee Follow us on Facebook, X, and YouTube at: www.facebook.com/NWSMilwaukee www.x.com/NWSMilwaukee www.youtube.com/NWSMilwaukee