A line of thunderstorms from the approach of a strong cold front resulted in straight-line wind damage in the Village of Sullivan. Numerous tree damage occurred and structural damage to a storage building.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS MKX wrote it up.
A line of thunderstorms from the approach of a strong cold front resulted in straight-line wind damage in the Village of Sullivan. Numerous tree damage occurred and structural damage to a storage building. The training of thunderstorms also resulted in the flash flooding and closure of some streets in Lafayette County.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Milwaukee, WI wrote its last area forecast discussion before the first event at Sep 19, 10:49 PM CST, 1 hour 31 minutes earlier.
Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 1149 PM CDT Wed Sep 19 2018 .UPDATE... Thunderstorms are moving east into western and southwestern Wisconsin at this hour. A gradual push to the east-northeast is expected overnight. The primary concern remains localized areas of heavy rain. A widespread 1-2 inches of rain is expected, which shouldn't cause too many issues, but localized areas of 3-4" aren't entirely out of the question. Should these enhanced areas of heavier rain develop, flash flood may become a concern in a few spots. && .AVIATION(06Z TAFS)... Convection will move into the region overnight. MVFR to IFR ceilings can be expected with this activity, along with occasional drops to IFR vis in and around the heavier thunderstorms. Rain/thunderstorms will lift north of the area Thursday as a warm front lifts across the region. Behind this front, southerly to southwesterly winds will become quite gusty, with 15-20 knots Thursday afternoon and evening. VFR will prevail Thursday afternoon and evening. && .PREV DISCUSSION... (Issued 943 PM CDT Wed Sep 19 2018) UPDATE... Convection has fired across Iowa, with a few small areas of thunderstorms pushing into southern Wisconsin. This should be the trend through the overnight hours, with a slow but steady eastward movement to the storms. Heavy rain remains the primary concern, though overall trends suggest that the heaviest rain will be transient enough to preclude the need for a Flash Flood Watch at this time. MARINE... Southerly winds will increase tomorrow across the lake as low pressure strengthens over the Plains. Southerly winds are expected to approach gales across the northern portion of Lake Michigan tomorrow night, with gales continuing into Friday as winds become westerly behind a cold front. Further south, winds will be between 25 and 30 knots. A Small Craft Advisory will likely be needed for the nearshore waters Thursday night and Friday. With the increasing winds, waves will build to 6 to 8 feet across the open waters Thursday evening, reaching their peak across the northern portions of the lake early Friday morning, with waves between 10 and 12 feet expected. High pressure will eventually build into the region over the weekend, with much less impactful wind and wave conditions by Saturday morning. PREV DISCUSSION... (Issued 621 PM CDT Wed Sep 19 2018) AVIATION(00Z TAFS)... Variable flight conditions are in place across the area right now. For the eastern terminals, VFR is prevailing behind the rain that fell earlier this afternoon. Further west, an area of MVFR ceilings has pushed into MSN, and will likely remain this evening. It remains unclear right now whether these lower ceilings will push further east with time, and if so, how far. Thunderstorms are already developing at this hour across far northern Iowa and southern Minnesota, and will push east into the region after midnight. MVFR to IFR conditions are likely with this activity late tonight into the first half of the morning tomorrow. Once this precipitation moves through/dissipates tomorrow morning, VFR will return to the area. However, south to southwest winds will become quite gusty by afternoon with 20 to perhaps 30 knot gusts at times. This will continue through the afternoon as a frontal boundary begins to approach the region from the west. PREV DISCUSSION... (Issued 356 PM CDT Wed Sep 19 2018) SHORT TERM... Tonight and Thursday...Forecast confidence is medium to high: An area of rain continues to push across southern Wisconsin this afternoon. This should continue to decrease in intensity as it moves east through late afternoon. Dry weather is then expected for the evening hours into early tonight. Attention will then turn to showers and storms that will likely develop as a warm front lifts through later tonight into Thursday morning. Could see a few stronger storms and some locally heavy rainfall. Models are in decent agreement in focusing the precipitation along and north of a Madison to Milwaukee line. It should be dry late Thursday morning through the afternoon with the warm front north of the area and the cold front well to the west. It should get warm and humid tomorrow given this setup. Could see places approach 90 toward the IL border given enough clearing. LONG TERM... Thursday Night...Forecast Confidence is Medium. Primary forecast challenge will be additional rain and severe chances with the cold front passage. As has been the trend the past day or so, the cold front arrival has trended later, with its passage now slated to be late Thursday night into the daylight hours of Friday morning. Diurnally speaking, not an ideal time for severe. The 12z suite of model output does indeed show a pretty sharp drop in CAPE across the region heading into the overnight hours Thursday night. As this occurs, model QPF sharply decreases. As a result there is some uncertainty with the forecast. There will be plenty of shear both in the deep layer and in the 0-3km layer, and forcing with the front should be potent enough to maintain convection as it moves into the area Thursday evening. As a result, convection that develops to our west and northwest tomorrow afternoon should be able to survive as it moves into southern Wisconsin. If a severe risk can be maintained, the best opportunity would be during the evening hours and west of a line from Fond du Lac to Madison to Darlington. Wind and hail are the primary risks, though 0-3km shear will be strong enough to be concerned about a tornado or two. Any rainfall will be progressive enough (and waning) to preclude any heavy rain risk. Friday through Sunday...Forecast Confidence is High. The front will clear southeastern Wisconsin by the mid morning hours and cold advection will spread over the region. Temperatures will be tricky given CAA and cloud cover. Will likely be a situation of initially falling temperatures leveling out and then a minor rise in the afternoon. Much of the day should be in the 60s, starting off in the lower 70s in the southeast before dropping behind the front. High pressure moves over the region Friday night into Saturday and dominates our weather regime through the weekend. Lows will be in the 40s and highs will be in the 60s to around 70 degrees. Monday through Wednesday...Forecast Confidence is Medium. Warm advection kicks in Monday, with modest moisture return. A cold front is still slated to move into the region Monday night into Tuesday and rain chances during this time frame remain prudent. More questions than answers forecast wise heading into the middle of next week as there are decent timing differences. Fundamental pattern change across North America will begin to take shape. The GFS is quicker to bring in an additional round of rain and then sharply cooler temperatures. The ECMWF is about a day later timing wise. Bottom line, sharply cooler conditions are looking more likely during the latter half of next week. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...None. LM...None. && Update...Boxell Tonight/Thursday and Aviation/Marine...Boxell Thursday Night through Wednesday...99
Hazardous Weather Outlook National Weather Service Milwaukee/Sullivan WI 406 PM CDT Wed Sep 19 2018 WIZ046-047-051-052-056>060-062>072-202115- Marquette-Green Lake-Fond Du Lac-Sheboygan-Sauk-Columbia-Dodge- Washington-Ozaukee-Iowa-Dane-Jefferson-Waukesha-Milwaukee- Lafayette-Green-Rock-Walworth-Racine-Kenosha- 406 PM CDT Wed Sep 19 2018 This Hazardous Weather Outlook is for portions of east central Wisconsin, south central Wisconsin and southeast Wisconsin. .DAY ONE...Tonight There is a moderate swim risk through this evening for the beaches along Lake Michigan. Breaking waves and currents are expected. Stay away from dangerous areas like piers, breakwalls and river outlets. A few thunderstorms are possible this afternoon into early this evening. Occasional cloud to ground lightning is the primary hazard expected. Additional thunderstorms are expected overnight tonight. A few strong storms are possible with hail to the size of pennies and wind gusts to 50 mph possible. Locally heavy rainfall is possible with this activity, especially for areas north of interstate 94. .DAYS TWO THROUGH SEVEN...Thursday through Wednesday Any lingering thunderstorms Thursday morning will exit to the north and east by the mid morning hours. There remains a chance of strong to severe thunderstorms Thursday evening, mainly along and northwest of a line from Fond du Lac to Madison to Darlington. Damaging winds and large hail are the main hazards expected. This activity is expected to weaken as it moves further into southern and southeastern Wisconsin overnight Thursday night. There is a chance for a few thunderstorms Monday night and Tuesday. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed Thursday evening. LMZ643>646-202115- Sheboygan to Port Washington WI- Port Washington to North Point Light WI- North Point Light to Wind Point WI- Wind Point WI to Winthrop Harbor IL- 406 PM CDT Wed Sep 19 2018 This Hazardous Weather Outlook is for portions of Lake Michigan. .DAY ONE...Tonight There is a chance of thunderstorms later this afternoon into this evening, with thunderstorms expected later tonight. .DAYS TWO THROUGH SEVEN...Thursday through Wednesday There are chances for thunderstorms Thursday into Thursday night, and again Monday and Tuesday. Small Craft Advisory conditions are likely later Thursday into Friday evening, as a strong low pressure system and cold front move through the region. A few gale force gusts are possible Thursday night into Friday afternoon. LMZ080-261-362-364-366-563-565-567-669-671-673-675-777-779-868- 870-872-874-876-878-202115- Lake Michigan Michigan City IN to St. Joseph MI 5 NM offshore to mid-line of lake.- Lake Michigan from Seul Choix Point to Rock Island Passage 5NM offshore to Mid Lake- Lake Michigan South of a line from Seul Choix Point to the Mackinac Bridge and North of a line from Charlevoix MI to South Fox Island 5NM offshore- Lake Michigan from Charlevoix to Point Betsie MI 5NM Offshore to mid lake- Lake Michigan from Point Betsie to Manistee MI 5NM offshore to Mid Lake- Lake Michigan from Rock Island Passage to Sturgeon Bay WI 5NM offshore to mid lake- Lake Michigan from Sturgeon Bay to Two Rivers WI 5NM offshore to Mid Lake- Lake Michigan from Two Rivers to Sheboygan WI 5NM offshore to Mid Lake- Lake Michigan from Sheboygan to Port Washington WI 5NM offshore to Mid Lake- Lake Michigan from Port Washington to North Point Light WI 5NM offshore to Mid Lake- Lake Michigan from North Point Light to Wind Point WI 5NM offshore to Mid Lake- Lake Michigan from Wind Point WI to Winthrop Harbor IL 5NM offshore to Mid Lake- Lake Michigan from Winthrop Harbor to Wilmette Harbor IL 5NM offshore to Mid Lake- Lake Michigan from Wilmette Harbor to Michigan City in 5NM offshore to Mid Lake- Lake Michigan from Pentwater to Manistee MI 5NM offshore to Mid Lake- Lake Michigan from Whitehall to Pentwater MI 5NM offshore to Mid Lake- Lake Michigan from Grand Haven to Whitehall MI 5NM offshore to Mid Lake- Lake Michigan from Holland to Grand Haven MI 5NM offshore to Mid Lake- Lake Michigan from South Haven to Holland MI 5NM offshore to Mid lake- Lake Michigan from St Joseph to South Haven MI 5NM offshore to Mid Lake- 406 PM CDT Wed Sep 19 2018 This Hazardous Weather Outlook is for the open waters of Lake Michigan. .DAY ONE...Tonight There is a slight chance of thunderstorms later this evening, with thunderstorms likely late tonight. .DAYS TWO THROUGH SEVEN...Thursday through Wednesday Gale force winds are possible late Thursday evening through early Friday evening across the north half of Lake Michigan. There are chances for thunderstorms Thursday into Thursday night, and again Monday night and Tuesday. www.weather.gov/mkx
The Quad Cities radar (KDVN), 128 km away, was scanning. The volume nearest the first event began at 06:17 UTC.
2 thunderstorm wind, 1 flash flood. Local standard time, as filed.
A few roads closed in Belmont and Darlington due to flooding.
A small number of trees blown down near Rome on highway Y.
Portions of a roof blown off a storage building. Numerous large tree branches down throughout Sullivan.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wisconsin in 2018Every state in 2018This day in weather historyWarnings in Wisconsin, September 2018
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 787907, 787569, 787567.