Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
622 FXUS63 KMKX 080356 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 1056 PM CDT Tue May 7 2024 .KEY MESSAGES... - Just a few lingering showers into the early morning hours. - More rain Wednesday night and Thursday with chances for thunderstorms as well. && .UPDATE... Issued 1055 PM CDT Tue May 7 2024 Just a few lingering showers are expected over the next 2-3 hours. Otherwise low pressure will continue to weaken over the northern Great Lakes tnt-Wed while shortwave ridging is expected aloft. A nice and warm day is expected for Wed with cooling near the lake. Gehring && .SHORT TERM... Issued 314 PM CDT Tue May 7 2024 Tonight through Wednesday night: Periods of rain and thunderstorms will continue across southern Wisconsin through this evening. The window for severe thunderstorms will be over the next couple or hours with the best chances across southeastern Wisconsin. The warm front is currently snaking across far southern Wisconsin. This is the area that highlights the best threat for strong to severe storms. Far southeast Wisconsin is also right along the better CAPE and effective bulk shear gradient which will give those areas the best chance for any type of supercellular development. Storms that ride along the warm front will have the best potential for any brief tornadoes over the next couple hours. The warm front will provide the surge of winds and just enough of a change in direction to be able to actualize any brief spin ups. Steep mid level lapse rates, upper level synoptic support, and the warm/moisture air advection across our forecast area make hail the primary threat. Can`t rule out some isolated damaging winds especially with any thunderstorms quickly collapses. Additional showers and thunderstorms are expected to develop later this afternoon and evening. As the environment becomes more worked over due to the ongoing rain/storms the chances for any strong to severe thunderstorms will decrease. The rain chances will persist until the warm/occluded front moves out over Lake Michigan late this evening. Overnight tonight, dry weather is expected. The dry conditions will be short lived as additional rain and storms are expected Wednesday afternoon and evening. For rain and storms Wednesday, the potential for strong to severe storms is very low. This will largely be in part to the easterly winds and the mid level lift/support remaining south of the state. An upper level trough will swing through the region providing some lift and there will be some decent moisture. Overall looking more like a stratiform type of set up with southern Wisconsin remaining on the northern side of the mid and sfc level troughing. The easterly winds look to undercut any potential for warmer air to move in near the surface as well which will keep any rain/storm elevated. So while there will be rain and a few claps of thunder, severe weather is not anticipated. Rain is likely to linger into the overnight hours Wednesday. Patterson && .LONG TERM... Issued 314 PM CDT Tue May 7 2024 Thursday through Tuesday: Rain is expected to continue through Thursday afternoon (50-60%) as mid-level cyclonic flow associated a shortwave trough and surface low pressure across Indiana and Ohio propagate eastward. Mid- level lapse rates of 5-6 C/km and mid-level CAPE values upwards of 100 J/kg combined with the synoptic scale influences across southern Wisconsin may give rise to a few rumbles of thunder on Thursday mainly along the Wisconsin/Illinois border, but primarily rain is expected especially into the afternoon. Heading into the weekend and early next week, a fairly unsettled pattern develops across the upper midwest with multiple mid-level shortwave troughs and ridges propagating across Wisconsin. Brief 500hPa ridging and warm air advection on Friday is expected across the state throughout the morning and early afternoon, allowing for quiet weather conditions Friday morning. A 500hPa shortwave trough and cold air advection will quickly follow this ridge providing synoptic scale ascent and steepening lapse rates such that showers and thunderstorms develop across southern Wisconsin Friday afternoon into Saturday morning (30-40%). A surface low is expected to develop across southern Ontario in response to the upper-level wave and sink southward across Lake Michigan providing for additional shower and thunderstorm development Saturday afternoon. Another brief 500hPa ridge then builds across Wisconsin again on Sunday. Model guidance begins to diverge in their solutions on Monday as another mid-level shortwave trough traverses the upper midwest through early next week. Falkinham && .AVIATION... Issued 1055 PM CDT Tue May 7 2024 Areas of ground fog may form tnt due to the rainfall, but it should remain rather limited in coverage and intensity due to very dry air just above the surface. Otherwise VFR conditions through Wed. MVFR Cigs and Vsbys will then develop as rain arrives Wed evening into the overnight. Cigs may fall below 1 kft for the overnight hours. Gehring && .MARINE... Issued 314 PM CDT Tue May 7 2024 Breezy east to southeast winds will prevail through much of Wednesday as a low around 29.1 inches lingers over the northern Great Plains. Periods of showers ans thunderstorms will continue through this evening. A few storms occlude be strong with gusty winds and hail, particularly this afternoon and early this evening. Best chance for strong to severe storms will be across the southern third of the Lake. Fog has begun to develop across the central third of the lake as warm moist air surges northward. The best chances for fog development will be for open water zones north of the warm front through this evening. Winds will shift to northeast over the lake Wednesday afternoon and evening as a second area of low pressure around 29.5 inches pass south of Lake Michigan. Additional periods of showers and thunderstorms are possible from Wednesday evening through Thursday, with conditions drying out Thursday night. Northerly winds will persist through Friday morning, prior to turning out of the southwest on Friday afternoon as a 29.7 inch low pressure moves across Ontario. Gales are not anticipated through the duration of the period. Patterson && .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