Marine Weather and Tide Forecast for Spring Green, WI

UPDATE
Issued 949 AM CST Thu Nov 6 2025

Main forecast challenge for today is the timing of gustier winds. If these winds begin to pick up during the mid-afternoon hours, marginal fire weather concerns develop with forecasted dew point temperatures in the low to mid 20s. Will be monitoring trends through the early afternoon. By the late evening hours, additional moisture from upstream will become capable of producing isolated showers, becoming more numerous overnight as boundary layer moistens. By this point, the front will likely be placed over southeastern Wisconsin, putting the main core of high probabilities for precipitation (60-80 percent) over that region.

MH

SHORT TERM
Issued 340 AM CST Thu Nov 6 2025

Today through Friday:

High pressure over the region now which will keep winds fairly light through at least this morning. However, this high pressure will quickly exit the region to the east later this afternoon, with perhaps some upper clouds building in over the course of the day as another system approaches from the west.
Into this afternoon winds will increase from the south and precip chances will increase into the evening, as the low to mid levels moisten up with strong LLJ and WAA. The signals for PVA in the upper levels continue to be modest, but the focus for ascent continues to be in large part driven by midlevel WAA/LLJ.

Models have largely come in line on precip chances tonight. The downward trend in pops for western parts of the CWA has continued with models suggestive of dry air potentially holding off precip in western parts of the CWA as the system pushes into the area. Then the influx of moisture is expected to occur right over the central and eastern parts of the CWA While some showery activity is expected in western parts of the CWA, models definitely show lighter and less widespread potential (30-50%).
The most likely outcome looks to be that more widespread showers develop in the central and eastern portions of the CWA as moisture and forcing increase with the LLJ moving directly overhead. Thus central and eastern parts of the CWA continue to see much better precip chances (50-80%, best chances in the far east). It should be noted that because moisture depth is still not profound in any way that its not expected to be a washout with QPF very likely remaining well under 0.25in for most if not all of the CWA Highest rainfall will very likely be seen on the southeastern parts of the CWA This system will push out Friday morning as the surface low pushes out toward the far easter Great Lakes region. A few showers on the backend of this system late Friday afternoon/evening now appears more likely with some TROWAL like effects at 700mb with some moisture as well as the upper trough bring PVA (with moisture). Forcing is relatively weak and moisture isn't deep but there is enough there, with CAMs hinting at it as well, to put some attention toward it. Otherwise expect breezy northwest winds behind the low Friday.

Kuroski

LONG TERM
Issued 340 AM CST Thu Nov 6 2025

Friday Night through Wednesday:

There may be a few light showers remaining Friday night, as some low level moisture and clouds linger within passing 500 mb vorticity maxima and associated CVA. Gusty northwest winds Friday evening should weaken and become north early Saturday, though this will allow for cold air advection to push through the area. Low clouds may linger into Saturday. Temperatures look to drop into the upper 20s to middle 30s Friday night, with mainly middle 40s on Saturday.

Low pressure should then develop over far northern Missouri Saturday, then into northern or central Indiana Saturday night.
This will be accompanied by a 500 mb shortwave trough, with a secondary trough pushing southeast into the area by early Sunday morning. There is a band of 850 mb to 700 mb frontogenesis response that shifts across the area, which would be in the layer of the best moisture. The path of this system may continue to vary over the next few days, and this will influence precipitation timing and types across southern Wisconsin.

At this time, it appears that mainly rain should spread east into the area Saturday afternoon, mixing with and changing to snow Saturday evening and overnight. The NAM is a little further north with the low track and has more of the main precipitation affecting the forecast area, versus the ECMWF/GFS which are a little further south and keeps the main precipitation over the southern and southeastern parts of the area. Ensembles seem to be more like the ECMWF/GFS with the low track, though the EPS has a somewhat deeper surface low than the weaker GEFS/CMC. The path of the 850 mb to 700 mb frontogenesis response will be key for any focused precipitation/snow.

For now, may continue to keep the higher PoPs (40 to 60 percent)
confined to the southern and southeastern parts of the area, though this may change in later forecasts. Any snow should be the wet, slushy variety and would mainly stick to the cooler grassy surfaces, with roads mainly wet. Areas near the lake would also be milder and may be more rain than snow.

However, heavier rates within the frontogenesis response band may keep bring some slushy accumulation onto roads. It is still early to pinpoint amounts given the low track uncertainty, so keep up with the forecast. It does not look to be an impactful winter weather event at this time.

Gusty northwest winds behind the strengthening low to the southeast on Sunday will bring strong cold air advection into the area. Some light snow showers may linger Sunday, as a deep 500 mb trough shifts into the region. Cold temperatures below seasonal normal values are expected, with lows Saturday night in the 20s and highs only in the middle 30s for Sunday. Ensembles suggest the coldest night will be Sunday night, with upper teens to lower 20s expected. Wind chills may be in the teens each night Saturday night into Monday night.

500 mb cluster analysis suggests the deep and anomalously low 500 mb height trough should gradually push east of the region by later Tuesday into Wednesday. A flat ridge may then push east toward and into the region by late in the week. A general warm air advection pattern may set up Tuesday into the rest of next week, which should allow for temperatures to return to more seasonable values.

Wood

AVIATION
Issued 949 AM CST Thu Nov 6 2025

VFR conditions continue throughout the remainder of today and into late tonight, with MVFR conditions possible as showers develop along a cold front during the late overnight hours, primarily from JVL to SBM eastward. Isolated showery activity is possible across all of southern Wisconsin during the evening to early overnight hours, but will cause minimal impacts.

Light southeasterly winds will become gusty at 20 to 25 kt from west to east mid-afternoon today into this evening. Gusts around 25 kt continue through the overnight hours, shifting to become southerly. The cold front late tonight into early Friday morning will shift winds to west-southwesterly, then west-northwesterly with gusts to 20 kt into Friday afternoon.

MH

MARINE
Issued 340 AM CST Thu Nov 6 2025

Light northwest winds will turn south today, as high pressure pushes out and low pressure pushes in. Southerly winds increasing this evening into tonight ahead of the approaching low pressure. There is increasing confidence in a round of gales during this period, with a Gale Warning now in effect for the entire lake tonight. Small Craft Advisory starts this afternoon and carries through 0z Saturday.

This low pressure system will then pass by just to the north Friday morning, with winds becoming west to northwest during the day Friday behind the low and an associated cold front. More periods of gusty winds will be possible the second half of the weekend into at least early next week. Additional gales becoming more likely especially for Sunday into Monday. Small Craft conditions expected at various times over the course of the next week.

Kuroski

MKX WATCHES/WARNINGS/ADVISORIES
WI...None.
LM
Gale Warning
LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563- LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779- LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...8 PM Thursday to 6 AM Friday.

Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646...3 PM Thursday to 6 PM Friday.