During the early evening hours of April 18th, a decaying line of thunderstorms produced damaging wind gusts across a swath from Knox to Sullivan Counties and eastward as far as Bartholomew County near Columbus. The damage was most intense in the Knox County area where numerous trees were downed.
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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 IND wrote it up.
During the early evening hours of April 18th, a decaying line of thunderstorms produced damaging wind gusts across a swath from Knox to Sullivan Counties and eastward as far as Bartholomew County near Columbus. The damage was most intense in the Knox County area where numerous trees were downed.
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 Indianapolis, IN wrote its last area forecast discussion before the first event at Apr 18, 8:24 PM EST, 29 minutes earlier. Its key messages:
Area Forecast Discussion National Weather Service Indianapolis IN 924 PM EDT Thu Apr 18 2024 .KEY MESSAGES... - Severe storms and are possible through the early overnight and locally heavy rain is possible through daybreak. - Cooler but dry Friday through Monday. Some frost potential mainly north Sunday morning, more widespread frost possible Monday morning. - Increasing rain chances next Tuesday, low chance for thunderstorms && .FORECAST UPDATE... Issued at 923 PM EDT Thu Apr 18 2024 Latest radar loop was showing a broken line of strong to severe thunderstorms moving east and southeast across east central Illinois with individual cells moving northeast around 30 mph. These storms were within a SW-NE oriented instability axis with SB CAPE to 1500+ J/kg. Further west, CAPEs were only around 500 J/kg, over the lower Wabash Valley, where the Severe Thunderstorm Watch extended to. HRRR has had a good handle on this broken line of convection and moves it over central Indiana 02z-06z. The combination of low level convergence from frontal boundaries and a surface low tracking through, moisture transport, instability and 30 to 40 knot deep shear has lead to some upstream damage over the LSX, ILX and PAH forecast areas. CAMS in good agreement the squall line will gradually weaken as it moves into the more stable air in place across east central and southeastern parts of central Indiana. That said, the Watch currently runs through 3 AM over parts of the lower Wabash Valley. Radar was showing additional convection further northwest across west central Illinois. This convection should roll across central Indiana overnight with instability waning, not be a course for concern regarding severe weather. Upstream 6 hour MRMS QPE was showing a few localized areas of an inch or so to 2 inches or so, but otherwise, don't atnicipate to many water concerns in addition to the ongoing river flooding. Wind gusts will approach 25 mph and turn to the northwest overnight in the wake of the cold front. The gusty winds and cloud cover will temper the cold advection and should keep temperatures to no lower than middle 40s to lower 50s by daybreak. && .SHORT TERM (This evening through Friday)... Issued at 317 PM EDT Thu Apr 18 2024 It's another day of above normal temperatures and a conditional threat for severe weather. Satellite shows high clouds currently over central Indiana while surface observations show temperatures warming into the 70s and dew points creeping higher over the SW counties. Thunderstorms will move in this evening, likely entering the state between 8 and 10 pm and tracking eastward through the overnight hours. The storms in question are currently over Missouri as of this afternoon. As they approach, winds will start to increase to around 10-15 mph with non-thunderstorm gusts possible through the night. Withe the severe threat, confidence remains low given the conditional nature. The latest CAMs show that variables may not line up quite right, but if they do damaging winds will be the main threat while an isolated tornado and isolated hail can't be ruled out. Isolated flooding may also be a concern as up to an inch of rain will be possible as the line of storms moves through a region that already has a pretty saturated ground. The best threat for severe weather will be over the SW counties where the best instability and moisture content will be. As the storms reach the area, CAPE of 500 to 1000 J/kg are expected, especially over those SW counties, but looks to drop to less than 500 J/kg over the following few hours. However, latest CAMs are showing less than impressive shear and helicity over the area and the surface low driving this system looks to lift as it reaches central Indiana. Lapse rates of 7 C/km may still be around when the line arrives but confidence is low and it seems more likely that those will have dropped off beforehand. The line of storms and the cold front causing them are expected to move out of the forecast area by sunrise or shortly after. Highs tomorrow will be lower and closer to normal, reaching only the mid 50s to low 60s. Otherwise, nice weather is expected for the day tomorrow with only partly cloudy skies remaining. && .LONG TERM (Friday night through Thursday)... Issued at 317 PM EDT Thu Apr 18 2024 Friday night through Monday... Quiet weather conditions are expected for several days as surface high pressure remains dominant over the region. Aloft, guidance shows a few upper level impulses traversing the region which could help to keep clouds around at times over the weekend. A weak LLJ associated with an upper disturbance moving through Saturday will likely help promote breezy conditions. Gusts up to 25 mph are possible during the day. Expect temperatures to trend cooler heading into the weekend due to cold air advection. Lows dropping into the 30s both Saturday/Sunday night combined with relatively light winds could support the potential for frost. There is higher confidence in frost Sunday night into Monday morning at this time since guidance shows much less cloud cover. Greater cloud cover from an upper level impulse Saturday night leads to higher uncertainty. Highs are generally going to range from the low 50s to near 60F over the weekend before warming up early next week. Monday night onward... Rain chances return late Monday night into Tuesday as a shortwave trough and associated low pressure system move across the Great Lakes Region. Return flow ahead of the approaching system should allow for temperatures to continue moderating. Sufficient moisture return combined with increasing dynamics supports likely POPs on Tuesday. The system is likely going to move out Tuesday night. Cold air advection and surface high pressure building in behind the departing low will allow for quiet weather conditions to return briefly before another system approaches late next week. && .AVIATION (00Z TAF Issuance)... Issued at 616 PM EDT Thu Apr 18 2024 Impacts: - Showers and thunderstorms moving in 00Z-02Z and ending 09z-11z - MVFR and briefly worse flying conditions will accompany the convection and MVFR or worse will likely hang around a few hours after the convection moves out - Damaging winds to 50 knots possible in the stronger cells - Winds will shift to NW, in the wake of the front, with gusts to near 25 knots, after 05z-15z Discussion: Showers and thunderstorms, with the leading edge likely linear, will sweep across central Indiana late this evening into the overnight. Deteriorating flying conditions will accompany the convection and low ceilings will hang around a few hours after frontal passage. Damaging winds are possible mainly with the leading line and later winds will turn northwest and gust to near 25 knots behind the cold front. && .IND WATCHES/WARNINGS/ADVISORIES... None. && UPDATE...MK SHORT TERM...KF LONG TERM...Melo AVIATION...MK
Hazardous Weather Outlook...UPDATED National Weather Service Indianapolis IN 940 PM EDT Thu Apr 18 2024 INZ021-028>031-035>049-051>057-060>065-067>072-191000- Carroll-Warren-Tippecanoe-Clinton-Howard-Fountain-Montgomery- Boone-Tipton-Hamilton-Madison-Delaware-Randolph-Vermillion-Parke- Putnam-Hendricks-Marion-Hancock-Henry-Vigo-Clay-Owen-Morgan- Johnson-Shelby-Rush-Sullivan-Greene-Monroe-Brown-Bartholomew- Decatur-Knox-Daviess-Martin-Lawrence-Jackson-Jennings- 940 PM EDT Thu Apr 18 2024 This Hazardous Weather Outlook is for Central Indiana. .DAY ONE...Tonight. Weather hazards expected... Elevated hail risk. Elevated thunderstorm wind damage risk. Elevated lightning risk. DISCUSSION... Scattered to numerous thunderstorms are expected this evening and into tonight. Severe storms are possible with damaging winds as the primary hazard. A lower risk for large hail, localized flooding, and tornadoes also exists. Lightning is a hazard with any thunderstorm. Storm motion will be to the northeast 30-40 mph. .DAYS TWO THROUGH SEVEN...Friday through Tuesday. No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation is requested this evening into the early overnight. && This product in graphical format...along with other weather... hydrological and climate information...at: http://www.weather.gov/erh/ghwo?wfo=ind http://www.weather.gov/ind WFO IND
The Evansville,IN radar (KVWX), 95 km away, was scanning. The volume nearest the first event began at 01:53 UTC.
9 thunderstorm wind. Local standard time, as filed.
A 60 mph thunderstorm wind gust was measured at this location.
Several large trees downed by thunderstorm wind gusts on the 11400 block of Sugar Lane.
Several trees and utility lines downed by thunderstorm wind gusts across Vincennes.
A 60 mph thunderstorm wind gust was estimated at this location.
Semi truck was overturned by thunderstorm wind gusts across US Highway 41.
A tree was downed by thunderstorm wind gusts along 1050 West in Lyons.
Multiple tree limbs and branches downed by thunderstorm wind gusts along State Road 54 near Eastern Greene Middle School.
Thunderstorm winds downed two hardwood branches.
A live and well established pine tree was snapped at the base by thunderstorm wind gusts.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Indiana in 2024Every state in 2024This day in weather historyWarnings in Indiana, April 2024
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: 1163716, 1163720, 1163717, 1163718, 1163719, 1163721, 1163722, 1163724, 1163723.