textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Dense Fog Advisory until 6 AM CST Friday for Lakeshore Counties. The dense fog may spread north and west tonight as winds remain light and low level moisture increases. - Moderate to briefly heavy rainfall rates are possible Friday into Friday night, with embedded thunderstorms expected. Strong to potentially severe storms are expected Friday afternoon into Friday night. All hazards will be possible at times from Friday morning through Friday night.

- Rain with perhaps a few embedded thunderstorms Tuesday into Tuesday night, with snow developing Tuesday night into Wednesday.

- Very mild Friday and again Monday and Tuesday.

SHORT TERM

Issued 1241 PM CST Thu Mar 5 2026

Tonight through Saturday:

Light winds, overcast skies and fog is the name of the game for the afternoon through tonight for southern Wisconsin. Low level moisture is high, light rain fell overnight further adding to that moisture and winds are light, the perfect recipe for lingering fog and stratus. The fog will slowly rise bringing visibilities above 1/4 mile but many areas may not see it completely clear. Visibilites are likely to remain around 2-4 SM miles through the evening. Under this pattern, widespread dense fog will likely (60% chance or higher) return again tonight. Counties along and south of I-94 and along Lake Michigan are the most likely to see dense fog return tonight. Those counties away from the lake and north of 94 wont get off scot- free but its more of a question on how dense it will be and how widespread. As winds turn southerly tonight and warmer air moves in the likelihood that all of southern Wisconsin sees dense fog grows.

Friday will be a fun peak at a high shear low CAPE severe day. Kicking things off early with a push of WAA Friday morning, widespread rain and thunderstorms will move into the state (POPs 80% or higher). Rain and storms will move in from the southwest to the northeast during the morning. Shear in the predawn hours will be around 200 m^2/s^2 and quickly increase to around 400 m^2/s^2 (or higher in some areas). The primary threat in the morning hours will be predominately hail, lightning and brief heavy rain. Dewpoints will still be a bit low as the breezy south winds kick in and storms are likely to be mostly elevated. By far the better environment for this early morning convection will be to our south, but in these high shear environments any CAPE we get will only enhance storms further. The primary area under the gun for stronger to severe storms in the morning hours will be far southern and southwestern Wisconsin.

Heading into the afternoon hours this is where storms become more scattered to isolated. For some this may be no storms again until the evening while other may wonder if there was ever a break in the rain/storms. The storm mode will slowly shift to supercellular during this time as shear remains high, dewpoints are on the rise with steady WAA and the sfc low starts to move into the state. This expands the threat area to all of southern Wisconsin overtime. The immediate lakeshore areas will be the last ones to see this flip over strong/severe storm chances as winds will need to shift to southerly or southwest. Any easterly component will undercut storm development until the winds shifts away from Lake Michigan. Once the sfc low and warm front start to move into the state mid to late afternoon, thats when storm coverage increases again and hazards increase. With any of the scattered convection that develop in the afternoon all hazards will be on the table including strong winds, hail and tornadoes. Storms that latch onto the warm front will be be the primary concern. With the strong shear, these storms are likely to be low topped so hail will become a secondary concern to winds and tornadoes. Again these storms are likely to be more isolated to scattered during this time frame. Brief heavy rain is possible.

Heading into this evening into the overnight hours the LLJ starts to kick in and Wisconsin will be in the warm sector. With the warm front continuing to push onward into northern Michigan, we will have high shear, low CAPE and a cold front barreling down on the CWA. All hazards will remain on the table as a line of thunderstorms develops along the cold front. This will make storms widespread again along a southwest to northeast line along the front. Right now the timing of the cold front has it moving in during the late evening hours around 8 to 10 PM in our west then progressing east with time. QLCS tornadoes (quick hitting smaller tors) will be mostly likely along the front, but can't rule out some slightly stronger or longer lived ones. Any segment of the line that starts to bow out will pose a high wind threat. Hail by far will be the smaller threat by this time in the day. Immediate lakeshore areas will again be battling the more stable air, but southwest winds should be strong enough to combat that cooler lake air. The cold front is not expected to clear the state until early Saturday morning around 3 to 5 AM.

With a frozen ground and chances for heavy rain all day there will be some nuisance ponding occuring as well. All rain is likely to be run off as the frozen ground fails to absorb it. River, creeks and lakes have room to take in the extra water will little concerns, but areas where the rain would normally soak in could have some ponding at times. Given all of this with multiple rounds of severe weather, this is a great time to review any safety plans you have and make sure you stay up to date with the forecast. Early season systems tend to catch people off guard. Make sure you have multiple ways to receive warnings especially options that will wake you up at night.

Once the cold front has cleared Saturday morning, there may be some light rain lingering on the back side. These will be very light showers and should exit to the east quickly. Lakeshore counties could see these light showers linger into the early afternoon. High pressure then builds in for some quiet after the storms.

Patterson

LONG TERM

Issued 1241 PM CST Thu Mar 5 2026

Saturday Night through Thursday:

Clear skies with light winds and lows down to the lower 30s are expected Saturday night due to high pressure briefly taking hold as it expands from the Plains. The northern stream upper level jet will set up across the southern Canadian provinces and a couple waves along it will drive our weather for early next week.

Weak low pressure crossing Ontario on Sunday will drop the associated cold front into northern WI by the afternoon. Southern WI will get sunny skies and gusty southwest winds Sunday afternoon. High temperatures Sunday will likely reach 60, and potentially 63 to 64 along the southeast lakeshore due to downsloping off the Kettle Moraine.

The next low crossing Ontario and the associated cold front may or may not dip into southern WI. The GFS and its ensembles maintain a stronger surface low and a push of the colder air briefly into srn WI, compared to the ECMWF. The only (minor) operational impacts of where this front actually goes are our wind directions and our high temps for Monday. The NBM model blend has highs in the upper 60s, which is right around the record high for Madison and Milwaukee. The frontal placement will create a more definite yes/no for breaking a record, especially for Milwaukee (possible onshore wind direction).

Yet another low will cross the Northern Plains and northern WI Tuesday. Ahead of it, expect our temps to remain mild, with over a 40 percent chance of exceeding the record high of 67 at MSN. There is a separate shortwave trough crossing the center of the country that may try to phase with the northern system as it crosses the Great Lakes. Rain chances increase over southern WI Tuesday afternoon and evening along the front, with greater than 75% south of a Port Washington to Janesville line. Slight chance of thunder with this in far southeast WI, with better chances over IL and IN.

Cooler temperatures and dry weather will return Wed-Thu, but temps will continue to be above normal.

AVIATION

Issued 1241 PM CST Thu Mar 5 2026

Low ceilings of 200 to 500 feet AGL will linger through Friday morning. The dense fog with visibility of 1/4 mile is still hanging on across southeast WI thanks to the light onshore flow off of Lake Michigan. The dense fog is sitting just offshore of Sheboygan, but is more diffuse inland at the SBM airport.

Dense fog is expected to return during the overnight hours, with highest confidence near Lake Michigan and medium-high confidence for a period of dense fog at MSN and JVL toward the morning hours between 08Z and 11Z. The dense fog may improve to BR after 11Z, but overall will linger until the widespread rain pushes in from west to east. Thunderstorms are likely along this initial band of rain. Look for scattered showers and a lower chance of lightning from late morning until mid afternoon. We could see some clearing during the afternoon, especially in southeast WI.

A round of thunderstorms is looking more likely during the evening hours and severe storms are possible.

Cronce

MARINE

Issued 1241 PM CST Thu Mar 5 2026

East to northeast winds will continue through much of today, as weak low pressure around 29.9 inches passes across the northern Ohio River Valley. Rain and drizzle are possible across the southern half of the lake into today, while marine dense fog with visibilities of 1 nautical mile or less continues across the southern third of the open waters today into tonight. Its possible that fog could start to expand further north this evening into tonight as southerly winds develop across the Lake.

Low pressure around 29.5 inches will develop in the central Plains Thursday night, and track toward the Upper Mississippi River Valley by Friday evening. This low will move near or just north of Lake Michigan later Friday night into Saturday morning, quickly moving into Quebec by Saturday evening.

As the low passes to the north, breezy southerly winds will develop for Friday afternoon and night, then shifting west to northwest on Saturday, with the passage of the cold front. Widespread rain and embedded thunderstorms will accompany the approaching and passing low Friday into Friday night. Breezy southwest winds are then forecast for Sunday into Monday.

Patterson

MKX WATCHES/WARNINGS/ADVISORIES

WI...Dense Fog Advisory...WIZ052-WIZ060-WIZ066-WIZ071-WIZ072 until 6 AM Friday.

LM...Dense Fog Advisory...LMZ080-LMZ644-LMZ645-LMZ646-LMZ671-LMZ673- LMZ675-LMZ777-LMZ779-LMZ872-LMZ874-LMZ876-LMZ878 until 6 AM Friday.