Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
580 FXUS63 KMKX 110925 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 425 AM CDT Tue Jun 11 2024 .KEY MESSAGES... - Showers and thunderstorms are possible at times Wednesday night into Thursday evening, with uncertainty with timing and placement of convection lingering. - Warmer and more humid conditions for Wednesday into Thursday. - A significant warm up still looks likely for Sunday into early next week. && .SHORT TERM... Issued 425 AM CDT Tue Jun 11 2024 Today through Wednesday: Middle to high clouds will gradually increase today, as a 500 mb shortwave trough approaches the region from the west northwest. This feature should move across the region tonight, along with a surface trough. Forecast soundings are showing just enough warm air and moisture advection in the 850 mb layer to bring in some weak to modest elevated instability later this afternoon and tonight. These features should result in widely scattered showers and perhaps a few thunderstorms from later this afternoon into the overnight hours tonight. CAMs are showing this general trend with the showers as well, with any more organized thunderstorms with the surface trough to the west of the area later this afternoon into early this evening. These storms should dissipate this evening with the loss of daytime heating. Another pleasant day is expected today, with highs in the lower to middle 70s. A southeast lake breeze may cool things down near Lake Michigan this afternoon. Steady warm air advection tonight into Wednesday will bring warmer and more humid air into the region, with southwest winds. It looks to remain dry for most of Wednesday, as any convection should remain to the west. Highs should reach into the middle 80s for most of the area, with a lake breeze possible near the shoreline in the afternoon. Wood && .LONG TERM... Issued 425 AM CDT Tue Jun 11 2024 Wednesday night through Monday: CAMs are showing convection developing somewhere near the warm front in southern Minnesota Wednesday afternoon, then shifting southeast into northern Iowa and perhaps clipping far southwest Wisconsin Wednesday night. Additional convection may develop further northeast across northwest Wisconsin Wednesday evening and perhaps shift southeast toward the area overnight. A lot will depend on the low level jet feeds into these areas, and where it focuses upward vertical motion. It should weaken somewhat overnight as it shifts more to the southeast over the area. All in all, probably will see weakening convection move southeast toward and into the area later Wednesday evening and overnight, perhaps lingering into Thursday morning. There is enough elevated CAPE for perhaps gusty winds and small hail, but think most of this activity should be weakening and bring some locally heavy rainfall at worst. Have likely PoPs for the rain and some thunderstorms over northern and western parts of the area later Wednesday night. Warm and more humid conditions will linger Thursday, with highs in the middle 80s and dew points in the 60s. Any chances for convective development on Thursday will depend on how far south the effective cold front develops. The models and ensembles seem to be trending south with the frontal position into northern Illinois, where most of them develop more convection Thursday afternoon and evening. The decaying showers and storms from overnight Wednesday night into Thursday morning may also help push the effective front southward. Kept chances for showers and storms going for Thursday afternoon and evening, mainly in southern and southeastern portions of the area closest to the front. Strong to perhaps some severe storms could occur in the moist and unstable airmass ahead of the front, but this could be in northern Illinois. Also lacking good upper level support over the region, so the front may be the only good trigger mechanism for storms. Will continue to watch this potential and where the front may set up. High pressure then moves southeast into the region for Friday and to the east Saturday, bringing dry conditions and more seasonable temperatures with less humidity. Ensembles remain fairly confident with a warm up for Sunday into early next week over the region. Cluster Mean forecasts generally show a 500 mb ridge axis building over the eastern Great Lakes region, with southwest flow over the northern and central Plains into the western Great Lakes region. This setup should allow for south to southwest winds to bring very warm and humid conditions back into the region. NBM is showing 25th to 75th percentile spreads of middle 80s to lower to middle 90s for highs for most of the area. Went with upper 80s to lower 90s for highs Sunday into Monday, and heat index values may climb into the middle 90s each day. In addition, rounds of showers and thunderstorms may occur, though there is a good amount of uncertainty in the timing and placement of frontal features and subsequent convection. Ensemble members continue to show more wetness than not, so another thing to watch for the extended period. Wood && .AVIATION... Issued 425 AM CDT Tue Jun 11 2024 Middle to high clouds will gradually move into the area today and linger tonight, before shifting east on Wednesday. Light south to southwest winds are expected today, with a southeast lake breeze possibly reaching the terminals near Lake Michigan this afternoon. Light southwest winds are then anticipated tonight into Wednesday. Any southeast lake breeze Wednesday afternoon may be confined to near the shoreline, and may stay east of the terminals near the lake. Warmer and more humid conditions are expected on Wednesday as well. Any showers and storms are likely to remain west of the area. Wood && .MARINE... Issued 425 AM CDT Tue Jun 11 2024 Winds will become south to southeast today, as high pressure around 30.0 inches moves to the southeast of the region. South to southwest winds will then linger tonight into Wednesday. Increasing southwest winds are expected for Thursday, ahead of an approaching cold front. These winds may reach Small Craft Advisory levels for the nearshore waters. There are chances of thunderstorms at times Wednesday night into Thursday evening, though there is uncertainty with the timing and location of storms. Later forecasts should get a better handle on where storms may occur during this time. Winds will shift to the northwest and north behind the front Thursday night into Friday, with high pressure around 30.2 inches moving into the region. Wood && .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