Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
103 FXUS63 KMKX 200806 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 306 AM CDT Sun Jul 20 2025 .KEY MESSAGES... - Chances for storms develop Tuesday night, and again Wednesday night into Thursday. Exact timing and intensity remains in question, with the most confidence in seeing widespread convection on Thursday. - Heat builds back into the region, with highs in the lower 90s Wednesday and Thursday. Heat index values of 100 to 105 degrees are possible on Wednesday. && .SHORT TERM... Issued 306 AM CDT Sun Jul 20 2025 Today through Monday: The cold front continues to slide WSW through southern WI early this morning. This is clearly delineated by low clouds on satellite and light northeast winds on surface observations. All precip associated with this front diminished. Meanwhile, a weak shortwave crossing southern WI kick off a few showers or sprinkles. The clouds will gradually diminish from north to south, beginning late in the morning. High pressure and dry air working into the area will give us dewpoints in the 50s by tonight, and thus lows in the upper 50s to around 60 inland from southeast WI. Our shower and storm chances will be largely protected by this high pressure today through Monday. The easterly winds will keep our temperatures in check, with highs ranging from the lower 70s east to upper 70s inland today, and upper 70s to lower 80s Monday. Expect mostly sunny skies with some diurnal cumulus clouds. Cronce && .LONG TERM... Issued 306 AM CDT Sun Jul 20 2025 Tuesday through Saturday: High pressure drifts east of the region on Tuesday, allowing southerly flow to resume and temperatures to climb rapidly (highs in the mid 80s, with low 80s further east near the lake). As surface pressure troughing east of the Rockies gradually evolves into a weak Surface low over central MN / northern WI late Tuesday, a chance for showers and thunderstorms is forecast to develop, but with the majority of the activity missing our CWA to the north (perhaps ~30% chances for our northern tier counties Tuesday PM). The aforementioned low pressure exits east, leaving a weak surface front / pressure trough southwest of it that slowly sags southward into later this week. This feature, combined with the proximity of the jet stream to our north leaves the potential for a few vort maxes to ride the crest of the ridge, yielding occasional chances for showers and storms through the remainder of the week. The majority of said chances on Wednesday (~30%) remain confined to the northern CWA (central / east-central WI) closer to the jet aloft. Chances peak area-wide on Thursday (40-50%, mainly afternoon / evening) as the aforementioned surface frontal boundary drifts closer, then taper down into Friday. Chances and timing will of course be subject to change, given the low predictability of the exact pattern. Heat is expected to peak mid week (especially Wednesday), with daytime high temps in the low to mid 90s, and dewpoints in the mid 70s (possibly even upper 70s). As such, heat headlines remain a possibility. Sheppard && .AVIATION... Issued 306 AM CDT Sun Jul 20 2025 IFR ceilings with pockets of LIFR spread into southern WI from northeast to south central in the wake of a cold front late last night into early this morning. Expect an improving trend in the same manner as drier air works into the region, with VFR everywhere by noon. Eventually clouds will become scattered or diminish everywhere by early afternoon. Brief and light showers are possible through mid morning out of mid level clouds due to a weak upper level disturbance. Cronce && .MARINE... Issued 306 AM CDT Sun Jul 20 2025 Northerly winds in the wake of a cold front will become decrease today as high pressure of 30.1 inches slides across the Upper Great Lakes. Winds will shift to the east on Monday as the high moves into Ontario. Winds will increase to around 20 knots and become southeast on Tuesday as low pressure of 29.5 inches approaches from the Central Plains. There are chances for storms Wednesday through Friday along a frontal boundary that sets up across the northern part of Lake Michigan. South to southwest winds will remain elevated Wednesday and Thursday. A low pressure trough around 29.8 inches will drop through the area Thursday night into Friday. Cronce && .MKX WATCHES/WARNINGS/ADVISORIES... WI...None. LM...None. && $$ Visit us at weather.gov/milwaukee Follow us on Facebook, Twitter, and YouTube at: www.facebook.com/NWSMilwaukee www.twitter.com/NWSMilwaukee www.youtube.com/NWSMilwaukee