textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Showers and thunderstorms expected this afternoon/evening, with coverage peaking between 4-10 PM. A few storms could produce large hail, particularly along & south of I-94 and US-18.

- Areas of light freezing rain & freezing drizzle remain forecast late tonight into early Wednesday morning (particularly 3-10 AM) to the north & west of the Milwaukee metro. Winter Weather Advisory is now in effect across Marquette, Green Lake, Fond du Lac, and Sheboygan Counties, where light icing is possible.

- Quick round of light to occasionally moderate snow remains forecast Wednesday morning & afternoon (~10 AM - 4 PM), with slushy accumulations up to half an inch.

- High precip chances (65-85%) Thursday evening/night, with expectations for some snow to mix in with rain late overnight into Friday morning.

- Additional precipitation chances develop Saturday into Sunday. High confidence in precipitation, but confidence in precipitation type and placement is lower. Snow is possible Sunday.

SHORT TERM

Issued 235 PM CDT Tue Mar 10 2026

Tonight through Wednesday:

Late This Afternoon through This Evening; Will be monitoring for blossoming elevated convection during the 4-10 PM time frame as elevated instability moves into the area. 18Z upstream soundings from ILX and DVN confirm the presence of steep mid-level lapse rates (~8+ C/km), which are likely to advect toward the US-18 and I-94 Corridors prior to elevated convective initiation. Combined with ample effective shear (~50+ kts), will thus be looking at an environment that will at least initially be favorable for mid-level mesocyclones, which combined with very flow freezing levels will support large hail potential in developing storms. Anticipate that this potential will be maximized along and south of the I-94 & US-18 Corridors, where the elevated instability plume will arrive earliest & be highest in magnitude. A stout inversion/very stable near- surface layer should preclude any damaging wind potential, though trends will nevertheless be monitored. Keep up with the forecast & have a way to receive warnings late this afternoon/early this evening, particularly if planning to be outdoors in southern Wisconsin. Expect new rainfall totals in the 0.25-0.5" range, with a few locally higher totals to 1" possible where any heavier thunderstorms track.

Late Tonight through early Wednesday Morning: Convective potential will wane as an upper shortwave/affiliated elevated instability pivots east of the area. Despite the loss of deeper ascent, residual warm advection/isentropic ascent in the 850-700 mb layer is expected to translate to drizzle potential from predawn through early morning, with potential peaking during the ~3-9 AM time frame. With cold advection becoming established near the surface, could thus see sub-freezing surface temperatures creeping in from northwest to southeast during the period of drizzle, leading to some freezing drizzle or very light freezing rain potential. Chances will be greatest to the north and west of the Milwaukee area, where colder temperatures will arrive sooner. Despite mild road temperatures from the recent warm up, do have some concerns for light icing impacts on elevated and untreated surfaces, particularly across far northern locations where temperatures will be sub-freezing through a larger portion of the overnight hours. Have thus issued a Winter Weather Advisory for said light icing impacts in Marquette, Green Lake, Fond du Lac, and Sheboygan Counties between 1 AM and 1 PM. With icing impacts waning by late Wednesday morning, may ultimately be able to let this Advisory go earlier than the scheduled 1 PM CDT expiration, with Wednesday morning trends dictating the final decision. Budget a few extra minutes of travel time if planning to be on the roads Wednesday morning, particularly to the north and west of the Milwaukee area.

Late Wednesday Morning through Wednesday Afternoon: A band of 850- 700 mb frontogenesis will quickly pivot through the area, bringing deep enough lift for cloud ice & a quick round of snow across the area. Expect an initially wet/slushy snow character, trending drier by early afternoon. Anticipate rates in the 0.25"/0.5" per hour, particularly directly beneath the frontogenesis, though progressive nature of the snow should limit residence time of said rates in any given location. Thus expecting snowfall accumulations near or below a half inch in the Wednesday snow. Will be monitoring for any changes through tonight.

Quigley

LONG TERM

Issued 235 PM CDT Tue Mar 10 2026

Wednesday night through Tuesday:

Mostly clear skies and decreasing winds are expected Wednesday night under the influence of high pressure centered well to the south. This should allow for near normal lows in the low to mid 20s. These sky and wind conditions should last into Thursday morning, with increasing clouds likely in the afternoon ahead of approaching low pressure. Southerly winds will also increase in the afternoon, pushing high temps a little above normal into the mid 40s most places.

Deepening low pressure is expected to move through northern Wisconsin Thursday evening and overnight, reaching northern lake Huron by early Friday afternoon. This forecast low track lines up fairly well with the latest ECMWF and GFS deterministic tracks and ensemble averages, which would keep the majority of snowfall north of the forecast area. Should see mainly rain Thu evening and overnight, with a brief mix with or change over to snow possible early Fri morning as the system is pulling away. Kept precip chances on the high end (70-90%) given the strength of this system. This is backed up by high probabilities for 24 hour measurable precip via latest ECMWF and GFS ensembles. Not out of the question for a rumble or two of thunder with the rain showers as the warm sector moves through Thu night. Southerly winds ahead of the cold front will likely be breezy Thu night, with stronger winds expected Friday behind the front. Could approach/hit Wind Advisory conditions Friday if this system pans out as latest models are suggesting.

Decreasing clouds and lighter winds are likely later Friday into Friday night as high pressure briefly moves through the area. Warm advection aloft ahead of the next approaching low is progged to move into the area later Friday night or early Saturday, which will bring increased clouds along with light precip chances (mainly snow). Deepening low pressure is then expected to move through the Great Lakes region Saturday night through Sunday night. This will have the potential to be a significant snow producer for locations north/west of the low track. As is common with deepening/phasing systems like this, the big question will be the track of the low and timing of the phasing, which will impact where the swath of snow sets up. Latest ECMWF and GFS ensemble MSLP averages take the low over or just to the south of Chicago, a favorable track for snow across at least the northern forecast area. There remains a pretty wide spread in individual ensemble members though, and this system is several days out, so confidence in snow totals for any particular location remains on the lower end for now. This storm will be worth keeping an eye on though.

Colder and drier conditions are expected to settle into the region behind the departing low early next week, as high pressure moves in from the northwest. Below normal temps are likely Monday and Tuesday.

DDV

AVIATION

Issued 235 PM CDT Tue Mar 10 2026

Mix of flight categories prevails early this afternoon as low stratus clouds erode from northeast to southwest. Areas experiencing clearing---particularly to the north and west of I-94 and Lake Michigan---will break into a brief period of VFR flight categories. Have maintained reduced flight categories at sites closer to Lake Michigan and along/south of I-94, where low level stratus will persist this afternoon. Given the sharp cutoff to the low level stratus deck, will monitor trends & amend accordingly through the remainder of the afternoon.

Reduced flight categories will return to all sites by late afternoon/early evening as an upper disturbance moves in from the southwest. Disturbance will bring -RA & embedded -TSRA by late afternoon, with updated mentions & timings being inserted in the 18Z update per latest model guidance trends. Will be closely monitoring radar trends through the next several hours for additional amendments to the going prevailing groups. Continue to expect the potential for some large hail in embedded convection, particularly along and south of I-94 where elevated instability will be greatest. Expect majority of CB to conclude by late evening.

Reduced flight categories will continue through the overnight/remainder of the period as northerly winds bring steadily colder temperatures to southern Wisconsin. Arriving colder air & continuing precipitation chances will lead to increasing -SN chances at all fields by mid-late morning Wednesday. Could see a period of light FZDZ or FZRA as the transition in p-type occurs, with the greatest potential for light icing impacts in the vicinity of SBM. Will be monitoring for any southeast expansions in anticipated FZRA/FZDZ coverage through tonight. If any such expansions occur, will update prevailing groups accordingly at south-central and southeastern aerodromes.

Quigley

MARINE

Issued 235 PM CDT Tue Mar 10 2026

Low pressure of 29.6 inches near the northern Kansas/Missouri border early this afternoon will head northeast the remainder of today into tonight, reaching southwest Michigan early Wednesday morning. Northeast winds will remain breezy today across roughly the northern two-thirds of the lake, becoming northerly tonight as the low passes over far southern Lake Michigan. Gusty northwest winds are likely Wednesday into Wednesday evening behind the low. Not out of the question for a few gusts to 35 knots during this period, particularly across eastern portions of the lake. Confidence for widespread gales isn't high enough at this point though for a Gale Watch or Warning. The current Small Craft Advisory may need to be extended through Wednesday evening based on latest winds and waves.

Lighter winds are likely Wednesday night into early Thursday as high pressure of 30.2 inches briefly moves through. Strong low pressure of 29.1 inches is then expected to move through northern Wisconsin into northern Michigan Thursday night into Friday. Increasing southerly winds are expected later Thursday into Thursday night ahead of the low. Though the cold lake may dampen the gust potential Thursday night, southerly gales will still be possible. There is a better chance for west to northwest gales on Friday behind the low. Could even see a few gusts approach storm force per latest models.

Winds are expected to ease Friday night into Saturday as high pressure of 30.2 inches moves in from the northwest. Another strong low pressure system is likely to move through the region late in the weekend into early next week, with another round of gales possible.

DDV

MKX WATCHES/WARNINGS/ADVISORIES

WI...Winter Weather Advisory...WIZ046-WIZ047-WIZ051-WIZ052...1 AM Wednesday to 1 PM Wednesday.

LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646 until 1 AM Thursday.