Marine Weather and Tide Forecast for Greendale, WI

UPDATE
Issued 711 PM CDT Wed Jul 15 2026

Could see a shower or storm fire along a backdoor cold front early this evening, but otherwise dry weather will persist through tonight. The main focus for the the overnight hours will be tracking the progression of smoke from Canadian wildfires into southern Wisconsin. The latest obs and HRRR forecast suggest the HRRR is a bit too fast with pushing the lower level smoke southwestward into the forecast area. The smoke may take a few more hours to progress farther into southern Wisconsin. The near surface smoke should largely stay confined to the northeast side of the frontal boundary, which is expected to stall roughly from the Wisconsin Dells to Kenosha overnight.

DDV

SHORT TERM
Issued 245 PM CDT Wed Jul 15 2026

Tonight through Thursday night:

As the Heat Advisory is lifted from the CWA tonight, temperatures are expected to begin to trend slightly cooler.
Overnight, low temperatures are expected to drop to the low 70s and potentially the high 60s near the lakeshore as a backdoor cold front stalls across the CWA Dewpoint temperatures will be in the low 60s near the lakeshore and high 60s inland, extending the humid conditions. Upper- level northwesterly flow along the jet stream creates a high potential for wildfire smoke from Canada and northern Minnesota to advect into Wisconsin, mainly impacting areas along and east of I-90 corridor bringing a reduction in visibility at times tonight through Thursday.

The persistent hot and humid airmass, especially for southwestern WI Thursday will keep temperatures in the upper 80s to around 90F across the region, but the stalling of a backdoor cold front and the presence of wildfire smoke may decrease the predicted high temperatures. This front also invites the potential for isolated to scattered showers and storms across the CWA, but the upper-level ridging and smoke may inhibit convection and lower precipitation chances (currently 20-30%).
If any thunderstorms do develop, expect them to be brief and pulsey in nature given the lack of shear. Nevertheless still will be capable of producing gusty winds as they collapse.
Otherwise expect poor air quality and decreased visibility to continue on Thursday, and potentially into Friday morning due to smoke at the surface.

Zawlocki/Wagner

LONG TERM
Issued 245 PM CDT Wed Jul 15 2026

Friday through Wednesday:

Main story of the extended will be the gradually cooler temps into next week along with periodic shower and thunderstorm chances.

Expect temps to gradually cool through the weekend. Friday and Saturday are still looking at above normal temps with highs in the upper 80s to lower 90s along with dewpoints in the upper 60s to lower 70s. However, not looking as hot as the start of the week as the upper-level ridge begins to flatten with a series of mid-level shortwave troughs traversing the region, which will bring along with it increased daily shower and storm chances.
Friday will be the first of these waves as mid-level vorticity treks through as the stalled boundary lifts northward as warm front ahead of a developing surface low in the Plains. This will place southern WI in the warm sector, but not much in the way of forcing to concentrate development. Nevertheless with the increasing PWATs and building instability still could see scattered shower and thunderstorm development. More likely pulse type convection if anything develops on Friday. Better forcing arrives Saturday as the surface low pushes over the Upper Great Lakes dragging a cold front through the area.
However, the latest guidance has the boundary sliding south through the morning and departing by the early afternoon. While forcing and moisture better align with a second mid-level shortwave trough arrival, the timing may not be conducive to build up enough instability for stronger storm development unless this system slows down in the next few model runs and/or remnant upstream convection/ remnant MCS moves into the area focusing redevelopment. Nevertheless, will see additional round of shower and thunderstorm chances for Saturday.

Once the cold front swings through the area on Saturday, it looks to usher in a cooler Canadian airmass with surface high pressure for Sunday. Looking at cooler temps with daytime highs in the low to mid 80s. Southerly flow along with a brief warm up and higher dewpoints return for the start of next week. Then expecting another mid-level trough to develop and traverse the Upper Great Lakes region later Monday into Tuesday. GFS and ECMWF both prog a deepening surface low across Ontario and dragging a cold front down across our neck of the woods. Again this will be the focus for another window for increase PoP chances. Given the better upper-level jet placement along with increased deep layer shear and instability, could not rule out seeing a some scattered stronger storm activity later Monday into Tuesday. Still plenty of time, for things to shift, but worth keeping an eye on given the more favorable upper-level setup at this time.

Otherwise, behind the early week system expect a stronger push of Canadian air to advect in toward the middle of next week and given the 6-10 day trends, there is even a potential to see near to below normal temps.

Wagner

AVIATION
Issued 711 PM CDT Wed Jul 15 2026

Could see a shower or storm fire along a backdoor cold front early this evening, but otherwise dry weather will persist through tonight. Isolated to scattered showers and storms will be possible tomorrow afternoon into the evening, mainly along and southwest of a line from the Wisconsin Dells to Burlington.

The other focus for the overnight hours into Thursday will be tracking the progression of smoke from Canadian wildfires into southern Wisconsin. The latest obs and HRRR forecast suggest the HRRR is a bit too fast with pushing the lower level smoke southwestward into the forecast area. The smoke may take a few more hours to progress farther into southern Wisconsin. The near surface smoke should largely stay confined to the northeast side of the frontal boundary, which is expected to stall roughly from the Wisconsin Dells to Kenosha overnight into Thursday. Visibilities could drop as low as 1-3 miles in areas that do see the smoke.

DDV

MARINE
Issued 245 PM CDT Wed Jul 15 2026

High pressure gradually breaks down this evening as a weak area of low pressure works its way across Lake Superior and down Lake Michigan. This has brought a northeasterly wind shift across the Lake and will continue Thursday. Additional seeing wildfire smoke from northern MN and northwestern Ontario reducing visibility across the northern third of the open waters to 1 nm or less at times this afternoon and likely to continue into Thursday. Thus a Marine Dense Smoke Advisory has been issued. Smoke is expected to continue to spread southward, but uncertain on how low visibilities will fall for the southern portions of Lake Michigan. Will continue to monitor if an expansion of the advisory will be needed.

Otherwise, lighter winds expected again on Thursday as another high pressure briefly builds back into the region before influence from a low pressure developing over the northern Plains pushes eastward through the weekend bringing more southwesterly flow for Friday into Saturday. Then as the low tracking northeastward, it will drag a cold front across the Lake resulting in northerly wind shift through the day Saturday with another high pressure building over the region for Sunday.
Additionally will see periodic shower and thunderstorm chances across the lake for the end of the week through the weekend.

Wagner

MKX WATCHES/WARNINGS/ADVISORIES
WI
Heat Advisory
WIZ046-WIZ047-WIZ051-WIZ052-WIZ056-WIZ057- WIZ058-WIZ059-WIZ060-WIZ062-WIZ063-WIZ064-WIZ065-WIZ066- WIZ067-WIZ068-WIZ069-WIZ070-WIZ071-WIZ072 until 8 PM Wednesday.

LM...None.