Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
295 FXUS63 KMKX 100238 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 938 PM CDT Wed Jul 9 2025 .KEY MESSAGES... - Mostly dry conditions expected into tonight. Some fog may occur inland from Lake Michigan and in the Wisconsin River Valley. - Storm chances (30-40%) return Thursday afternoon and evening as an MCV moves through the upper Mississippi Valley. - Heat and humidity ramp up Friday into Saturday, along with the next widespread chances (~60-75%) for showers and thunderstorms. - Brief break from the humidity on Sunday, with muggy conditions and afternoon storm chances returning Monday-Tuesday. && .UPDATE... Issued 938 PM CDT Wed Jul 9 2025 Dry conditions are expected through the rest of the night now that the sun has gone down and we`ve lost the day time heating. There remains a chance for fog to develop overnight tonight for inland areas. Dewpoints of 64 or greater have settled in areas that remain west of the lake breeze prior to sunset. Dewpoints are at there highest in southwestern and far western Wisconsin. These areas will have the best potential for fog to develop under the clear skies and light winds. Dense fog isnt anticipated to develop overnight. Patterson && .SHORT TERM... Issued 245 PM CDT Wed Jul 9 2025 Tonight through Thursday night: A few showers can`t be ruled out along a combined lake breeze/sfc trough this afternoon along the Wisconsin/Illinois border. Otherwise most of the area should remain dry. Tonight, patchy fog is anticipated inland from Lake Michigan and in the Wisconsin River Valley. Tomorrow, models have ramped up chances (now 30-40%) for rain during the afternoon compared to previous forecasts. This is owed to an MCV from dying convection in Iowa Thursday morning, moving overhead by Thursday late afternoon and evening. PVA associated with this feature will kick off shower and thunderstorm activity over the Upper Mississippi Valley during the early afternoon, with this activity translating east into Thursday evening. While widespread severe weather is not expected model soundings depict modest mid-level lapse rates around 7 C/km amid SBCAPE around 2000 J/kg and dry low- levels. The steep lapse rates would support hail, provided the storm doesn`t collapse first amid the weak effective shear around 20 knots. Any collapsing storms may pose a localized downburst threat with high winds. CMiller && .LONG TERM... Issued 318 PM CDT Wed Jul 9 2025 Friday through Wednesday: Still a bit of uncertainty with model disagreement in the extended period, but the general consensus is that a warm front is expected to lift north over the area by Friday morning. This will usher in a more humid air mass. There may be a few showers/storms along the initial push of WAA Friday morning. An elongated trough is then expected to kick off thunderstorm activity Friday evening along the Mississippi River and that activity will work east into the overnight hours, generally weakening as it travels east. The trough will slowly swing through on Saturday as a cold front. With its slow movement, there may be a enough time for some destabilization in southeast Wisconsin, and a second round of thunderstorms may form Saturday afternoon before exiting east over Lake Michigan. The cold front will then pass Saturday night, with less humid and quieter conditions expected Sunday. A warm front is then expected to approach Monday, bringing back humidity and chances for storms Monday afternoon and Tuesday. CMiller && .AVIATION... Issued 938 PM CDT Wed Jul 9 2025 North to northeast winds will continue to weaken and become more easterly to southeasterly by daybreak Thursday. South to southeast winds will continue into Friday. Overnight tonight, winds may periodically be light and variable. Mostly clear skies and light winds will bring a chance for some patchy fog to develop inland from Lake Michigan. Low lying areas and river valleys, especially the Wisconsin River Valley will have the best potential for fog development. Visibilites are expected to fall to around 1-4 SM. Dense fog is not anticipated. Scattered rain and thunderstorms will be possible late Thursday afternoon into Thursday night. The current system we`re tracking is to the west in the Dakotas and Nebraska. As it gets closer and timing confidence increases, precipitation will be added to the TAFs. Patterson && .MARINE... Issued 230 PM CDT Wed Jul 9 2025 High pressure will linger over the Upper Great Lakes into at least Thursday night. Breezy north winds over the southern half of the lake will give way to generally light and northerly winds tonight through Thursday. A few thunderstorms may move over the southern half of the Lake Thursday night. A warm front will then lift north Friday morning, change winds to southerly over the lake. Winds remain light until they turn southwesterly Saturday ahead of an approaching cold front, where gusts may reach 20 knots. Winds then ease and become westerly following the frontal passage Saturday night into Sunday. CMiller && .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