Marine Weather and Tide Forecast for Greendale, WI

SHORT TERM
Issued 250 PM CDT Tue Apr 22 2025

Tonight through Wednesday night:

Later this afternoon and evening, the surface warm front continues to be the focus for any convective initiation. Most models still keep the warm front to the south of the CWA in northern Illinois with convection largely remaining south. There remains a chance (20-30%) that the the warm front does not sag as far south as expected and if that is the case, convection would likely initiate further north over at least parts of southern WI. Regardless of where the front sets up the risks for strong to severe storms seems fairly limited based on what CAMs are currently showing however 1000-1500 J/kg of instability and 40ish kts of effective shear is suggestive of some organized convection with the primary risks being hail and damaging winds.
The winds seem to be the larger threat given some of the sounding profiles suggestive of a bit of an inverted V with strong enough DCAPE to bring some damaging wind potential.
Overall chances remain limited for strong to severe storms, however.

Later overnight into Wednesday expect that warm front to slide back north introducing increased precip/storm chances (40-60%)
with some morning/early afternoon influence from a weak shortwave with additional influence into the afternoon from increased WAA (weak LLJ) and low to midlevel moisture. The level of instability through the day Wednesday is a bit more uncertain but models are at the least bringing 500-1000J/kg of MUCAPE to the region. The strong to severe storm potential seems fairly similar to today (in northern IL), but convection seems likely to be more consistent through the morning and into the afternoon. This may limit the upper bounds of our instability throughout the day in addition to causing cold pools in these areas further limiting the potential for stronger surface based storms. Outside of some isolated hail, general storms seems most likely with this. Wed evening/night we will gradually loose our moisture and instability with largely just showers and weak storms expected (mostly further west) but gradually dissipating across the region and shifting further north as the warm front slides further north. Cannot rule out some stronger evening storms but by the overnight period the environment is weak with CAMs suggestive of little to no activity during this period.

Kuroski

LONG TERM
Issued 250 PM CDT Tue Apr 22 2025

Thursday through Friday night:

Thursday may end up being largely quiet with the surface trough/warm front lifting well north of the area according to models. There could be some ongoing activity in the northwest parts of the CWA Thursday from the surface trough but there is also some forcing aloft with a shortwave in the area. Influence from the shortwave isn't all that noticeable in models but with moisture aloft it appears as though the influence might be a bit underdone. Perhaps the day Thursday could see a bit more activity though it would still likely be focused further northwest. Into Thursday night there remains significant differences between models on what will occur with the surface low as the EC, NAM and Canadian deterministic models all have the low coming through Thursday night into Friday bringing more widespread showers and perhaps some weak storms, while the GFS develops the low further south and east and thus brings less precip overall. By Friday night things come back into line with models suggestive of higher pressure pushing in behind the front with drier conditions as an upper level ridge slides in.

Kuroski

Saturday through Tuesday:

Dry weather is expected on Saturday into Sunday with surface high pressure and a mid level ridge overhead. Friday and Saturday will be the cooler in the wake of the low.

Another system will approach the state Monday and Tuesday. South winds ahead of low pressure in the northern plains will bring a warm and humid air mass into southern Wisconsin. There is a chance for showers and storms during this time. It is early to pin down the details, but storms could be strong to severe. There is favorable instability and shear both days with an approaching mid level trough.

Marquardt

AVIATION
Issued 250 PM CDT Tue Apr 22 2025

Drier conditions are more likely (70-80%) the rest of this afternoon into the evening with the warm front sagging south and bringing storm chances to northern IL while remaining on the drier side in southern WI. We cannot rule out a few storms/showers pushing north of the WI/IL border but it appears less likely at this point. Any storms would carry some VSBY restrictions possible. Overnight tonight into Wednesday the warm front will kick back north bring scattered showers and storms to southern WI with the best chance toward southwest WI. Models indicate some MVFR CIGS will be possible across parts of southern WI Wednesday but may be more SCT to BKN. Precip/storm chances will continue through the day Wednesday before gradually dissipating or at least becoming more isolated into the evening and overnight hours. Again, MVFR/IFR VSBYS will be expected with heavier showers or storms Wednesday.

Otherwise expect light to modest winds today, predominantly from the south but turning more west as the front sags south. Near the lake a lake breeze will likely develop bringing more east to southeast winds behind it into this afternoon. Light southerly winds will dominate Wednesday.

Kuroski

MARINE
Issued 250 PM CDT Tue Apr 22 2025

Light to modest southeast winds later this afternoon into the evening as weak high pressure lingers in the eastern Great Lakes region with a low pressure system sits around the northern ND/MN border. The surface low will continue to weaken as it gradually lifts northeast into Wednesday morning. The weak warm front will then lift north into Wednesday morning and continue gradually lifting north through Wednesday night into Thursday. Expecting periodic shower and thunderstorm chances along the frontal boundary as it slides north. Winds will remain fairly light through Wednesday as the low pressure to the north weakens as it lifts northward into central Canada. Expecting to see the front to gradually wash out into Thursday as high pressure builds across the Upper Great Lakes. Winds look to be variable through the end of the week before gradually increasing into Friday as another weak surface low works it way across the Midwest from the Plains.

Kuroski

MKX WATCHES/WARNINGS/ADVISORIES
WI...None.
LM...None.