Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
054 FXUS63 KMKX 290318 AAA AFDMKX Area Forecast Discussion...UPDATED National Weather Service Milwaukee/Sullivan WI 1018 PM CDT Fri Jun 28 2024 .KEY MESSAGES... - Showers and storms will exit from west to east during the overnight hours. The threat for severe storms is low, but lightning is a threat for those outdoors. - River flooding and high water levels remain elevated into this weekend. Additional rises will be possible with any heavier rainfall. - Dangerous swim conditions on Lake Michigan will continue along southeast WI beaches this evening with a high swim risk for Sheboygan and Ozaukee Counties` beaches. && .UPDATE... Issued 1018 PM CDT Fri Jun 28 2024 A line of showers and thunderstorms tracked east-southeast through portions of southern WI, mainly north of I-94, for the majority of the evening. Lightning was on the leading edge of the area/line of storms. The outflow boundary sagged southward over the last couple of hours which now has the main line of storms lined up along the I-94 corridor from Madison to Milwaukee. Showers are spotty in far southern WI. We have been watching the cluster of thunderstorms track from Grant County now to Dane County. The lack of MUCAPE and shear is preventing any organized structure to this cluster of storms, so heavy rain and lightning are the threats. Thankfully, the cluster is moving along so flash flooding risk is low. The main cold front is way back in southeast MN. We could see showers between this round that will exit shortly after 1 AM and the main front that is not expected to move through until 7 or 8 AM. A meso model or two suggest scattered convection ahead of and along that front, but there is not a lot of confidence in seeing that hold together all the way through southern WI with the lack of strong dynamics. Cronce && .SHORT TERM... Issued 315 PM CDT Fri Jun 28 2024 Tonight through Saturday night: There`ll be a bit of a break in the rain late this afternoon but as we go into the evening hours, a convectively forced MCV should provide impetus for another round of rain during the overnight hours. CAPE values in our area, in combination with this MCV, are expected to be elevated above the surface and weak at around 500 J/kg, with most of the better shear confined to along or south of the Wisconsin-Illinois border. As a result, stronger storms may be limited over our area, but rumbles of thunder and some lightning may occur with tonight`s activity. Along with the thunderstorms, dangerous swim conditions will linger at southeast WI beaches this evening into tonight with a high swim risk for Sheboygan and Ozaukee Counties` beaches. Gusty southerly to southeasterly winds will keep waves high until winds ease after midnight tonight and become slightly offshore with time. As we go toward daybreak, activity should wane in the wake of the MCV as subsidence spreads over the area, and a dry period may occur as a cold front sags southeast through southern WI. This front will clear out 70 degree dew points and cloud cover that will build and linger overnight, but some 60 degree dewpoints may remain. A secondary cold front will move through during the afternoon hours, and with the morning cold front providing clearer skies and leaving some 60 to 65 degree dewpoints behind, SBCAPE should build to 1500 J/kg in an environment marked by 30 knots of effective shear. Convergence along the front tomorrow afternoon may create some widely scattered thunderstorms, with coverage limited by weak forcing aloft and skinny CAPE profiles that may cause dry air entrainment. If any storms get going and mature, dry low levels may promote isolated gusty winds and modest lapse rates may support small hail. Activity should then clear with the front as it moves southeast Saturday evening. CMiller && .LONG TERM... Issued 313 PM CDT Fri Jun 28 2024 Sunday through Friday: High pressure takes hold Sunday into Monday, promoting dry and cool conditions as daytime highs will only reach around 70 on Sunday and around 75 on Monday. Conditions then look to turn active Tuesday through Friday as long-range models depict multiple frontal passages and waves of WAA promoting almost daily chances for showers and storms, typical of an active summertime pattern in the upper midwest. CMiller && .AVIATION... Issued 1018 PM CDT Fri Jun 28 2024 A period of IFR ceilings are possible between this exiting round of showers and storms (ending around 1 AM) and the main cold front (exiting southeast WI around 7 AM). MVFR is more likely. Light rain showers are also possible during this time. There is a low chance of scattered storms ahead of an along the main cold front early in the morning. Look for VFR diurnal cumulus clouds Saturday. A few pop-up showers and thunderstorms are possible during the afternoon. Cronce && .MARINE... Issued 258 PM CDT Fri Jun 28 2024 Breezy south to southeasterlies will continue into the overnight hours as low pressure of 29.5 translates eastward overnight. Tomorrow, a pair of cold fronts will slide southeast with time, bringing the winds southwest midday, and then northwest by tomorrow evening. Gusty northwest winds are then expect Saturday night through Sunday. CMiller && .MKX WATCHES/WARNINGS/ADVISORIES... WI...Beach Hazards Statement...WIZ052-WIZ060 until 1 AM Saturday. LM...Small Craft Advisory...LMZ643-LMZ644 until 1 AM Saturday. && $$ 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