Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
345 FXUS63 KMKX 030944 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 444 AM CDT Mon Jun 3 2024 .KEY MESSAGES... - Warm/muggy conditions prevail for the first half of this week. - Showers and thunderstorms expected later this morning through this evening. There is a conditional (level 2 out of 5) risk for some severe thunderstorms this afternoon and evening, with wind and hail as the primary threats. - Additional rounds of showers and thunderstorms Tuesday and Wednesday. - Northwest winds bring cooler and drier air to southern Wisconsin for the second half of this week. && .SHORT TERM... Issued 440 AM CDT Mon Jun 3 2024 Today and Tonight: An MCV currently over northwest Iowa will continue to drift northeastward, working with disorganized nocturnal convection to its north (SE Minnesota and northwest WI) to generate outflow boundaries capable of triggering fresh convection further east (over our CWA) late this morning into this afternoon. SBCAPE up to 2000 joules this afternoon coupled with deep shear of 25 to 45 kts will be sufficient for some organized storm clusters, with some strong to severe storms possible this afternoon and evening. Upscale storm growth and clustering along both remnant and fresh outflow boundaries could lead to training storms (which impact the same area multiple times), capable of a flash flood threat. Hail and damaging wind gusts would be the primary severe weather threats. Isolated tornadoes cannot be ruled out at this time. Storm coverage and intensity is likely to decrease late tonight as instability dwindles. Sheppard && .LONG TERM... Issued 440 AM CDT Mon Jun 3 2024 Tuesday through Sunday: As southerly warm/moist advection continues at the surface, another shortwave trough rotating through the 500mb pattern could trigger warm sector convective initiation, leading to scattered showers and thunderstorms late Tuesday afternoon (40 to 60% chance). However, model guidance suggests that more organized storms will be lined up along the cold front to our west, with 85% precip chances arriving late Tuesday evening through Tuesday night. As the cold front completely crosses the CWA Wednesday morning, precip chances begin a gradual decline (30-60% in the morning), with only 15-30% chances for showers and storms in the cool sector of the parent low pressure (Wednesday afternoon). Cool / dry air advection on northwesterly winds continues through the end of the week, with daytime highs in the low to mid 70s likely for all areas Thursday and onwards. Sheppard && .AVIATION... Issued 440 AM CDT Mon Jun 3 2024 VFR conditions continue early this morning, with showers and thunderstorms gradually developing and approaching from the southwest, with arrival timing and chances reflected in the TAFs. In the event storms arrive late this morning (western airports only, KMSN and KJVL) they are unlikely to be severe, but may produce sub-severe localized wind gusts and lightning. Some strong to severe storms are possible (all areas) this afternoon and evening, with damaging wind gusts, hail, and frequent lightning as the primary threats. Broken cumulonimbus cloud bases are likely to remain VFR altitude (generally 4000 ft) for the earliest storms, then gradually lower towards 3000-ft MVFR levels later in the event, perhaps 2000-ft or lower for areas that see repeated hits from thunderstorms (mid- afternoon through evening). As shower and thunderstorm coverage decreases tonight, lingering clouds at 3,000 to 10,000 ft are expected. In the event that gaps can form in these clouds, fog formation will be possible, and a few patches of dense fog cannot be ruled out. Only 15 to 25% precip and thunder chances for the late tonight period (may be excluded from TAFs depending on confidence level). Sheppard && .MARINE... Issued 440 AM CDT Mon Jun 3 2024 An area of low pressure over southern Alberta to the northern Great Plains deepens to around 29.2 inches today, then drifts northeastward into Ontario through Wednesday. Southerly winds develop today, continuing though Tuesday night. Then a cold front crosses Lake Michigan Wednesday, causing winds to veer westerly. Westerly winds look to continue through the end of the week as the meandering low over south- central Canada weakens to around 29.4 inches. Expect periods of showers and thunderstorms from this afternoon through Wednesday. With humid air moving in from the south today and tonight, fog may develop late tonight through early Tuesday over the waters, and patches of dense fog are possible. Model guidance suggests that northwestern areas of Lake MI will be most susceptible to fog formation. Sheppard && .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