NWS Milwaukee Forecast Discussion
912 FXUS63 KMKX 031543 AAA AFDMKX Area Forecast Discussion...UPDATED National Weather Service Milwaukee/Sullivan WI 1043 AM CDT Fri Jul 3 2026 .KEY MESSAGES... - Our severe chance has increased for southeast WI and the timing is much earlier (now through 2 PM). A few severe storms with strong winds and hail are possible. - Additional batches of showers and storms continue tonight through Sunday. Keep up with the forecast if planning to be outdoors. - Trending quieter early next week. && .UPDATE... Issued 1043 AM CDT Fri Jul 3 2026 The thunderstorm complex that was over Iowa that was expected to dissipate is actually holding together. This is bringing an area of showers and thunderstorms into south central and southeast WI (toward WI/IL border) through the next couple of hours. With the morning sunshine in southeast WI, we have managed to get a sliver of higher instability there. The latest RAP analysis is showing +2000 j/kg and bulk shear is 35-40kt along the WI/IL border. This is our chance for severe thunderstorms today. The storms that are in northwest IL are expected to reach the Kenosha area around 1 PM. The big change for our overall forecast is that while we can still see afternoon showers and thunderstorms, our severe chances will be lower this afternoon due to all the morning showers and cloud cover. Cronce && .SHORT TERM... Issued 200 AM CDT Fri Jul 3 2026 Today through Tonight: Synopsis/Mesoanalysis: Regional radar mosaics remain busy tonight following an evening of strong to severe storms across southern Wisconsin. Said storms laid down an elongated outflow boundary, which currently stretches from the Chicago metro to just south of the Des Moines, Iowa vicinity. Thanks to a southwesterly low level jet in place regionally, ascent up & over the outflow has allowed convection to blossom to the north/cool side of the boundary from Iowa across northern Illinois. Some of this activity could leak north into southern Wisconsin through the remainder of the overnight hours, particularly to the south of I-94 and US-18. Further to the west over the Central Plains, additional widespread convection is ongoing over Nebraska. While these storms will remain well west of the area through tonight, high-res forecast guidance is hinting at an affiliated remnant shortwave/MCV crossing the region this afternoon. Whether this feature will be able to trigger storm development will depend on air mass recovery in the wake of predawn showers/storms regionally, with forecast trends being monitored through the rest of this morning. In the event storms were to form this afternoon, a few would be capable of producing gusty straight line winds. Additional showers and storms are possible during the predawn hours Saturday. With clouds & areas of showers/storms around the region, temperatures are expected to remain below heat headline thresholds today. Rest of the Overnight: Will be monitoring convective trends over Iowa and northern Illinois as storms regenerate over the top of outflow boundaries laid down by earlier evening convection. Expect that development will continue over these regions through the remainder of the overnight hours given a persistent southwesterly low level jet & attendant overrunning. Whether activity manages to propagate further north/into southern Wisconsin remains more uncertain, as the low level air mass remains worked over in the wake of multiple batches of convection last evening. Best convective potential will be along/south of I-94 & US-18, where elevated instability values remain a touch higher compared to further north. Not expecting severe weather in the event convection makes it back into the area, though heavy downpours would be possible. Have maintained the existing Flood Watch over Sauk Co given antecedent wet conditions & convective chances. If appreciable precip stays south of the region through the rest of the overnight, watch will be allowed to expire as scheduled at 7 AM. This Afternoon & Evening: Forecast uncertainty increases as a remnant shortwave/MCV from storms currently over the Missouri Basin moves across the region. If sufficient destabilization can occur in advance of the feature, it could help trigger scattered storm development during the ~12-8 PM timeframe, with a few severe storms with gusty winds and hail possible. If, however, morning convection over Iowa/Illinois/southern Wisconsin holds better instability to the south of the region, storm coverage would be minimal. Will thus be monitoring trends closely, as what storms do through the morning hours will go a long way in determining what the radar looks like come afternoon. Will continue to provide forecast updates through the morning. Tonight: Will be watching for more thunderstorms during the predawn hours as one or multiple clusters of convection move into the Mississippi Valley from the Plains. Expect that convective intensities will be waning as these storms approach, likely limiting severe potential. Will continue to monitor trends and provide updates through today. Quigley && .LONG TERM... Issued 200 AM CDT Fri Jul 3 2026 Independence Day through Wednesday: The upper ridge over the eastern CONUS will gradually diminish as mid level westerlies win out as they head east of the Great Lakes region Sunday and Monday. Unfortunately, our region will remain in a battle zone of sorts for Independence Day into Sunday. From a large scale pattern perspective, it is prudent to expect an convective system or two. However the timing and details will be heavily determined by how the mesoscale is altered by convective behavior and remnant boundaries Friday and Friday night. At this time, from a large scale pattern perspective, it appears the better rain chances shift east of the area on Sunday, but this will have to be closely monitored day to day. Early next week, ensemble consensus is for a mid level ridge to build over the Rockies, nudging our upper level pattern into northwest flow. This will deliver typical July conditions with lows in the 60s and highs in the 80s. Small ripples from time to time are to be expected in this northwest flow pattern, though timing these individual waves is a futile exercise. Bottom line, there will be a good amount of dry time, and intermittent chances for showers/storms with any ripples. Gagan && .AVIATION... Issued 625 AM CDT Fri Jul 3 2026 Current area of showers and storms west of the area should have a tough time holding together as it tries to shift east into the morning hours. May see a few showers or storms make it to Madison or Janesville terminals later this morning or midday, before weakening. Otherwise, middle level clouds may be scattered to broken at times today, depending on how long the precipitation to the west keeps going. Winds should remain fairly light today into tonight. This will help determine if more showers and storms develop this afternoon and early evening across the area. There is a decent amount of uncertainty on timing and areal coverage of any showers or storms, so kept PROB03 mentions going in the TAFs for all terminals this afternoon into early evening. Stronger storms could bring strong winds and hail. There may be more chances for showers and storms at times tonight, with the better chances toward the Illinois border. Again, kept PROB30 mentions going in TAFs, though Janesville and Kenosha may see prevailing showers or storms after midnight tonight. Wood && .MARINE... Issued 200 AM CDT Fri Jul 3 2026 High pressure around 1020 mb will remain parked over the Ohio Valley and Appalachian Mountains into tonight. Meanwhile, a trough of low pressure will remain over the Great Plains through tonight. A weak low pressure area may then organize and slowly move across Wisconsin and Lake Michigan from Saturday afternoon into Sunday, or pass farther south across Illinois into the Ohio Valley. Modest south to southwest winds will become lighter today. Light to modest winds are then forecast for the weekend, but with some uncertainty on wind direction given low confidence in the track of the low. A stormy period is expected for central and southern Lake Michigan through the weekend. Patchy marine fog will be possible at times as warm and humid air flows over the relatively cooler lake. Quigley && .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