Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
677 FXUS63 KMKX 050321 AAA AFDMKX Area Forecast Discussion...UPDATED National Weather Service Milwaukee/Sullivan WI 1021 PM CDT Tue Jun 4 2024 .KEY MESSAGES... - Scattered thunderstorms will continue tonight, with the main concern being locally heavy rainfall. - Northwest winds bring cooler and drier air to southern Wisconsin for the second half of this week. && .UPDATE... Issued 1021 PM CDT Tue Jun 4 2024 Scattered thunderstorms will persist through at least early tonight ahead of an approaching cold front, likely gradually losing their strength through the night as instability decreases. Locally heavy rainfall is the main concern at this point given already saturated soils across the area. Unlike last night though, storms have been moving at a good enough speed to limit the flooding threat. DDV && .SHORT TERM... Issued 240 PM CDT Tue Jun 4 2024 Tonight through Wednesday night: A negative tilt shortwave will continue to lift northeast this afternoon and with increasing instability with upper 60 to near 70 degree DPs we should (30-50%) expect scattered storm development later this afternoon into the evening. However with little to no shear we expect these storms to largely be of the popcorn style with limited severe risk with the only real risk for hail up to an inch and brief strong gust from collapsing storms. Latest CAMs suggest some storms but mostly weak and lacking persistence. As storms weaken as they slide northeast into the mid evening that were associated with the shortwave we will then see the effects of the longwave trough in west central Canada ejecting another wave of energy through the area. This, in association with the cold front, will be the cause of convection through the afternoon in MN but the remnants of this convection will try to slide through in the late evening and overnight hours. This is expected to be weak if not actively dissipating as it pushes across southern WI. Latest CAMs suggest that this and any remaining activity from the early shortwave will likely (70%) be weak. Given PWATs upwards of 1.5 inches any storms could again be efficient rain producers, but with storms likely being transient and scattered expect mostly an isolated flooding risk. Following the front we will see a brief period of quiet weather behind the shortwave ejection overnight but then upper low in Canada will again eject some shortwave energy into the western Great Lakes for Wednesday afternoon and evening. Given some decent midlevel lapse rates and enough low level moisture behind the cold front we could expect a few weak storms and showers but nothing severe would be anticipated at this time. Kuroski && .LONG TERM... Issued 240 PM CDT Tue Jun 4 2024 Thursday through Tuesday: We will remain under cyclonic flow until Friday night and then a brief break in that flow (with weak ridging) is possible. With a secondary closed upper low moving into south central Canada right behind the exiting one, another embedded shortwave is expected to trek across WI Saturday afternoon or night. The upper low will remain overhead through Sunday night, so there is a chance for showers and perhaps isolated thunderstorms each afternoon as well. Highs will be around 70 through Monday, with lows in the lower 50s. Cloud cover should be primarily diurnally driven. Winds will be out of the west-northwest through this period, and the speeds will be higher, around 15 to 22 mph, each afternoon with peak daytime heating and mixing. Cronce && .AVIATION... Issued 1021 PM CDT Tue Jun 4 2024 Scattered storms will continue through at least early tonight, with locally heavy rainfall possible. Though storm intensity will likely decrease overnight, there will be a threat for lightning until the cold front clears the forecast area early Wednesday morning. Mainly VFR conditions will persist ahead of the cold front, outside of lower ceilings and visibilities within thunderstorms. Lower ceilings are then expected to move through for a short while behind the cold front, with clearing skies west to east during the day Wednesday. Winds will shift to westerly behind the front tomorrow, with breezy winds likely in the afternoon. A shortwave will then bring a chance for showers and a few storms to southern Wisconsin tomorrow evening. DDV && .MARINE... Issued 240 PM CDT Tue Jun 4 2024 A low pressure trough will continue to slide east across south central Canada tonight with southerly winds continuing ahead of the associated cold front. Showers and thunderstorms are possible late this afternoon through tonight. The cold front will cross Lake Michigan Wednesday morning, causing winds to veer westerly. Widespread showers and storms will end by around noon Wednesday. Scattered showers are possible each afternoon through the weekend. Westerly winds continue through the end of the week as low pressure over south central Canada weakens. 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