Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
996 FXUS63 KMKX 261527 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 1027 AM CDT Sun May 26 2024 .KEY MESSAGES... - Widespread showers (with a few rumbles of thunder possible) continue this morning into the early afternoon. - Scattered showers and thunderstorms in the 3 PM to 8 PM timeframe today, with a very small potential for severe thunderstorms with hail and/or wind gusts along and south of US-18/I-94. Showers clear out later in the evening. - Southeast winds and building waves lead to a Moderate Swim Risk for Lake Michigan beaches today. - Chance for showers/storms Monday and Tuesday, particularly in the afternoon hours (roughly 40% chance), but quieter weather midweek. && .UPDATE... Issued 1025 AM CDT Sun May 26 2024 The first batch of WAA-driven rainshowers currently overspreads most of the CWA, moving northeastward towards Sheboygan. Some weak thunderstorms are present behind this initial line, but said storms are likely to remain weak and elevated for the remainder of the morning, given the southeast flow off of Lake Michigan. Most will lose thunder potential before entering the CWA. Diffluent / cyclonic flow and PVA aloft, coupled with continued 850mb moist advection will allow skies to remain overcast for most of today, preventing the sun from generating much surface based instability. A dry slot wrapping into the low could allow for some breaks in the clouds over far south and southwest WI in the mid to late afternoon, but even then, it would likely be mostly cloudy. One would expect the shortwave trough passing this afternoon to steepen mid-level lapse rates, yet models indicate that thermal ridging at 500mb could linger longer than previously anticipated, further reducing afternoon destabilization. That said, as the center of the surface low approaches southwestern WI, the wind field will then allow the surface low to drag the warm front into our CWA without the stabilizing effect of Lake MI, bringing SBCAPE up to 1000 joules and MLCAPE > 500 joules to areas along and south of I-94/US-18. The exact values / positioning of said instability depends heavily on the exact warm frontal positioning, which is still tough to predict, but a marginal (level 1 out of 5) risk of severe weather is generally expected from 3 PM to 8 PM CDT today, along and south of the I-94/US-18 corridor. Storm strength / coverage gradually decreases later this evening, leaving most areas dry by midnight. Sheppard && .SHORT TERM... Issued 300 AM CDT Sun May 26 2024 Today through Monday night: Showers and weak storms will gradually push in by around daybreak this morning as the surface low and corresponding upper shortwave lifts northeast into the region. This system looks likely to make for a fairly wet morning and early afternoon with any individual area looking at a 3-4 hour period of mostly moderate rainfall (far west/northwest CWA will see rain last much of the day). Largely, chances for storms seems fairly limited but with some weak instability, especially along and south of I-94 some rumbles of thunder cannot be ruled out. Now in the far southeast the situation is a bit different as rain should hold off until at least noon which could increase severe risk. However, models continue to keep the warm front south of the region with limited instability overall. This will limit the potential for severe storms as anything would have to be elevated and even then instability will be very limited. However we cannot rule out the very slight potential for some stronger wind and small hail. As the initial swath of rain swings through the surface low will begin moving overhead the region. We should (70%) see the dry slot impact the region for a few hours keeping things dry for a few hours in the mid to late afternoon. However later in the afternoon and into the early evening some showers and maybe even a few storms will be expected in association with the surface low. Given cooler conditions aloft we should expect some better lapse rates which could (10%) give some secondary risk for hailers during this period. Models suggest largely just showers but conditions support at least weak potential. The deepening surface low will gradually push northwest into the northern Great Lakes region and into Ontario. Monday may feature some additional precip chances (35-45%) due to some additional shortwave activity in the region along with some moisture. Best chances for precip are focused further west but there will be some storms chances for much of the CWA. Storms will be at least partially diurnally driven as instability increase somewhat into the afternoon across the area. Stronger storms not expected at this time due to lack of shear. Southeast winds and building waves are likely to create Moderate Swim Risk conditions on today for Lake Michigan beaches. A High Swim Risk cannot be ruled out but trends have pushed nearshore waves down this afternoon. Kuroski && .LONG TERM... Issued 300 AM CDT Sun May 26 2024 Tuesday through Saturday: Tuesday will also feature continued chances (40-50%) for showers and storms, though weak, due largely to the upper trough digging through the region. While there remains some uncertainty with this upper trough and its progression from central Canada into the western Great Lakes region the trend points toward better chances for a day similar to Monday with diurnal convective influence but with less certainty in regards to location of where we should see shower/storms and how widespread it will be. Recent trends do suggest best chances will be further north. By midweek it appears for at least a short period we will finally return to drier conditions with higher pressure sliding in ahead of ridging aloft. Friday looks a bit more uncertain but most models suggest a drier solution with any precip concerns holding off until at least Saturday. The weekend looks as though it will feature a system coming through but models disagree on timing. However that will be something to watch as the week progresses. Kuroski && .AVIATION... Issued 1025 AM CDT Sun May 26 2024 Widespread rainshowers continue to gradually lower cloud ceilings, with MVFR / Fuel-Alt levels expected this afternoon (beginning with western areas closer to the core of the low pressure), followed by IFR tonight. As the core of the low passes, expect southeast winds to veer west and then northwest this evening. Rainshowers should decrease to scattered coverage this afternoon, but would then be more likely to possess thunder (50% chance). Airports south of KMSN and KMKE would be the most likely to experience any stronger storms, with a very low chance (risk level 1 out of 5) for severe thunderstorms with wind gusts and hail. Showers exit from southwest to northeast late this evening, with KSBM being the only airport with much of a chance for rain (50%) after midnight. Cloud ceilings gradually lift on Monday. Sheppard && .MARINE... Issued 300 AM CDT Sun May 26 2024 High pressure over Lower Michigan will move east into New England today, while low pressure lifts from Kansas into western Illinois by this afternoon, and then to southern Lake Michigan by late tonight. This will result in increasing southeast to east winds across the lake for today, with showers and thunderstorms likely at times today, largely for the southern portion of the lake. That low will then progress northeastward to Lake Huron by Monday afternoon, with winds quickly turning northwesterly as the low departs. West to northwest flow will persist into mid week, with winds gradually weakening over time as high pressure eventually builds into the region. Slight chance for small craft conditions to be met this afternoon and again Monday afternoon. Kuroski && .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