Two rounds of thunderstorms impacted central Indiana during the Sunday before Memorial day with a quick microburst in the morning followed by a QLCS tornado across Knox county followed by a swath of thunderstorm winds. Damage beyond Knox county was more widespread but not quite as intense as the EF-2 tornado.
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 IND wrote it up.
Two rounds of thunderstorms impacted central Indiana during the Sunday before Memorial day with a quick microburst in the morning followed by a QLCS tornado across Knox county followed by a swath of thunderstorm winds. Damage beyond Knox county was more widespread but not quite as intense as the EF-2 tornado.
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 May 26, 9:31 AM EST, 35 minutes earlier. Its key messages:
Area Forecast Discussion National Weather Service Indianapolis IN 1031 AM EDT Sun May 26 2024 .KEY MESSAGES... - Thunderstorms likely later this morning through early afternoon and again this evening. - Some storms will be severe with damaging winds the primary threat. - Low rain chances continue through Tuesday with dry conditions expected for mid-late in the work week. && .MESOSCALE UPDATE... Issued at 1031 AM EDT Sun May 26 2024 Bottom line up front: Line of convection moving into central Indiana may still strengthen some as it moves through, with gusty winds, small hail, lightning, and heavy rain the threats. Not a lot has changed in thinking with this initial line of storms. Observations in Illinois have shown wind gusts around 35 mph with some reports of small hail. Steep mid-level lapse rates remain ahead of the line. Also, some heating continues ahead of the line, albeit limited thanks to cloud cover, and low level moisture continues to push north. Thus, while some strengthening may occur, storms will still generally produce small hail and perhaps some wind gusts around 40 mph. An isolated stronger storm remains possible. More stratiform rain with embedded thunder will linger behind the initial line of storms. && .SHORT TERM (Today and tonight)... Issued at 259 AM EDT Sun May 26 2024 We will attempt to further refine timing of one, potentially two, rounds of thunderstorms and explain forecast caveats, uncertainties, and potential alternate scenarios. These situations are complicated with mesoscale processes that are difficult to resolve even at this close time range often dictating the outcome. Current thinking is round #1 of thunderstorms will arrive around or just before noon and exit by around 4pm, and round #2 of thunderstorms would arrive around 8pm and continue until around 1am. See analysis below for more details. Phasing of a northern stream shortwave trough with an active subtropical jet has occurred in the central Plains early this morning, resulting in extensive convection within a reservoir or strong instability. This seems to be the origin of the lead shortwave trough shown in the model PV and vorticity fields arriving in our region early today. These convectively-induced perturbations are sensitive to model errors with their parent convection, most notably when cold pools are not adequately modeled. This explains some of the variance on timing and magnitude of an MCS or remnant MCS that is expected to reach Indiana late morning/midday. There appear to be two possible scenarios with the first round: Scenario #1. A mature MCS that is able to sustain during the diurnal minimum given downstream reservoir of at least modest instability. In this scenario a cold pool-driven forward propagating convective system would move into Indiana potentially earlier than the aforementioned window, perhaps as early as mid-morning. An attendant strong/damaging wind threat would accompany this system, along with heavy rain and lightning. Negatives for this scenario to occur include: (a) MCS may outpace the midlevel wind maxima and stronger shear values resulting in cold pool dominance and weakening (c) a tendency for upshear propagation to dominate over downshear propagation resulting in a more southeastward path, given expected southwesterly oriented low-level jet. Positives for this scenario to occur include: (a) models' tendency to underestimate cold pool strength, especially with convection spawn in such an impressive thermodynamic environment upstream in the Plains, (b) magnitude of moisture that is expected to surge northward later tonight as a result of mass response from the upstream trough driving higher instability than typical during the diurnal minima. Scenario #2. A weaker band of remnant convection driven by warm/moist advection that could be delayed until the nose of stronger midlevel jet arrives, possibly not reaching Indiana until midday/early afternoon. This scenario would not be driven by a substantial cold pool and convection would likely be rooted above the surface and not particularly impactful aside for rain and some lightning threat. Latest observational data shows that the modified continental air mass that moved in yesterday wasn't particularly intrusive into lower latitudes. Mid-60 to low-70 degree surface dew points are located near or just south of the Ohio River and will return northward early this morning in response to strengthening isallobaric flow in response to the upstream mid-latitude system. In fact, this may result in some advection fog, albeit likely not widespread or significant. A developing MCV is now apparent across northwest Missouri with extensive trailing convection into northeast Oklahoma. Although this trailing convection is intense, it doesn't appear to have formed a consolidated cold pool yet and a mature cold pool-driven system is at least a few hours from forming, most likely. We will continue to monitor trends closely to our west to assess the placement and magnitude of a forward propagating system in Missouri, or whether upshear propagation begins to dominate as mentioned above, causing a more southeastward track into southern Illinois and west Kentucky. A reasonable worst case scenario is a mature forward propagating MCS moving into Indiana mid-late morning with an attendant damaging wind threat. 0-3-km shear vector orientation and magnitude would support QLCS mesovortices near and north of the apex of any localized surges, and the low-level thermodynamic environment is sufficient for a nonzero tornado risk. The most likely scenario is an MCS moving into Indiana by late morning and progressing through with strong to locally damaging winds, but perhaps weakening and progressing slower as shear becomes weaker. The CAMs that support the most intense MCS also indicate a fairly strong wake mesohigh (i.e., a couple recent runs of the HRRR), so we'll need to watch for a potential enhancement of gradient winds for a brief period as the MCS departs if the stronger scenario does play out. We are fairly confident in a period of wake mesoscale subsidence before additional thunderstorms become possible by evening. What is not currently clear is the duration of any trailing stratiform rain during the midday into the afternoon. Trailing stratiform rain becomes more likely when the cold pool dominates and shear magnitude is relatively weak, and this appears to be a plausible scenario. Given the difficulty of the models in handling the convective system to begin with, rain cessation during the afternoon this is one of the greatest uncertainties for today's forecast, and we'll need to monitor trends and refine precipitation probabilities throughout the day. Unlike some mid-summer scenarios where tropospheric flow is weak and a convectively-overturned air mass can eliminate subsequent convective development, there should be fairly swift mass movement with this system. Depending on the degree of overturning of the upstream environment, a ~40-50-kt low-level jet should be effective at replenishing moisture and instability by evening across at least a portion of our area. A second shortwave trough is expected to approach by then resulting in a period of ascent and convective development both along its advancing front, and probably also along differential mixing zones that may be along the edge of remnant cold pools. Most of this redevelopment should occur to our southwest, and perhaps into the southwest portion of our forecast area, and then move into at least the southern portion of our area. This part of the forecast is also uncertain and will depend on how the first round of convection plays out. Nonetheless, the parameter space should become supportive of severe storms with the second round. Veered low-level flow and relatively straight hodographs with shear vectors aligned nearly parallel to the advancing front would suggest cell mergers and quick upscale growth over Illinois, with only a low chance of supercells ahead of the frontal convection into Indiana. Large hail and damaging wind would be the threats, and in a reasonable worst case scenario any cells that can interact with modifying remnant cold pools would have some potential for tornadoes. This is most likely southwest of our area. Our area may be impacted more after peak convective intensity into the mid-late evening hours, before convection weakens and shifts east by the predawn hours Monday morning. Localized flooding is possible where multiple heavy rain-producing thunderstorms occur. 1-hour flash flood guidance is around 1.5-2.0 inches. && .LONG TERM (Monday through Saturday)... Issued at 259 AM EDT Sun May 26 2024 Monday through Wednesday... Broad upper troughing will remain across the eastern CONUS through the first half of the extended with multiple shortwaves expected to move across the region. This will keep low rain chances in the forecast at times. Moisture return should remain limited ahead of these disturbances as a cold front settles across the southeast so look for QPF amounts to remain light. Isolated light showers or drizzle may be ongoing during the first half of the day Monday with broad cyclonic flow still in place, mainly across northern portions of the area. A better chance for precipitation is then expected towards the evening and overnight hours as an upper level impulse approaches. Subtle moisture return and daytime heating may provide a narrow corridor of modest instability for isolated thunderstorms from central IL to west/southwest portions of central IN during the evening. Forecast soundings also show sufficient deep-layer shear which could support a organized storms containing strong sub-severe wind gusts. Severe weather appears unlikely at this time due to limited amount of instability. A second shortwave is expected to provide another opportunity for precipitation late Tuesday. The best chance for rain will be across N/NE counties closer to the upper wave where stronger forcing should be in place. Weak moisture return will keep rainfall amounts light. A cold front associated with this system will result in a brief cooldown midweek. Lows are expected to fall well into the 40s Thursday morning. Ensemble guidance is in good agreement that surface high pressure begins to build in Wednesday providing quiet weather conditions. Thursday onward... Upper ridging and surface high pressure will likely provide quiet weather conditions for Thursday and Friday. Surface high pressure then begins to slide east on Saturday with the weather pattern expected to become more unsettled as an upper trough moves into the region. Other than the brief cooldown midweek temperatures are expected to generally remain near seasonal through the extended. && .AVIATION (12Z TAF Issuance)... Issued at 619 AM EDT Sun May 26 2024 Impacts: - First round of storms 15-20z; second round 00-05z - Southwest winds will gust to 25 knots Sunday; higher near storms Discussion: There is still a low probability of brief MVFR ceilings or visibility early-mid morning as low-level flow strengths and moisture returns. Otherwise, thunderstorms are possible at any TAF site late morning/midday and again this evening. Timing is uncertain and coverage appears limited enough to handle with VC and PROB30 for now. Gradient wind gusts may peak around 25 knots at times today from the south-southwest. && .IND WATCHES/WARNINGS/ADVISORIES... None. && MESOSCALE...50 SHORT TERM...BRB/Melo LONG TERM...Melo AVIATION...BRB
Hazardous Weather Outlook National Weather Service Indianapolis IN 947 AM EDT Sun May 26 2024 INZ021-028>031-035>049-051>057-060>065-067>072-271400- 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- Including the cities of Delphi, Flora, Williamsport, West Lebanon, Lafayette, West Lafayette, Frankfort, Kokomo, Attica, Covington, Veedersburg, Crawfordsville, Lebanon, Zionsville, Tipton, Fishers, Carmel, Noblesville, Anderson, Muncie, Winchester, Union City, Farmland, Parker City, Clinton, Fairview Park, Rockville, Montezuma, Rosedale, Greencastle, Plainfield, Brownsburg, Danville, Indianapolis, Greenfield, New Castle, Terre Haute, Brazil, Spencer, Gosport, Martinsville, Mooresville, Greenwood, Franklin, Shelbyville, Rushville, Sullivan, Carlisle, Shelburn, Farmersburg, Linton, Bloomfield, Jasonville, Worthington, Bloomington, Nashville, Columbus, Greensburg, Vincennes, Washington, Loogootee, Shoals, Bedford, Mitchell, Seymour, and North Vernon 947 AM EDT Sun May 26 2024 This hazardous weather outlook is for central Indiana. .DAY ONE...Today and Tonight. Thunderstorms will move northeast through central Indiana late this morning through mid afternoon. Additional thunderstorms are likely this evening and tonight. Some storms will be severe with damaging winds being the primary threat. Large hail and tornadoes are also possible. The highest chances for severe storms will be with the evening storms. Heavy rainfall could cause localized flooding. Storm motion will generally be from the southwest or west at around 40 mph. .DAYS TWO THROUGH SEVEN...Monday through Saturday. Isolated thunderstorms are possible for parts of the area on Tuesday. .SPOTTER INFORMATION STATEMENT... Spotter activation will likely be needed today and tonight. && 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
Special Weather Statement
National Weather Service Indianapolis IN
1024 AM EDT Sun May 26 2024
INZ060-261515-
Sullivan IN-
1024 AM EDT Sun May 26 2024
...A strong thunderstorm will impact portions of Sullivan County
through 1115 AM EDT...
At 1023 AM EDT, Doppler radar was tracking a strong thunderstorm over
Palestine, or 7 miles east of Robinson, moving northeast at 40 mph.
HAZARD...Winds in excess of 40 mph and penny size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor hail damage to vegetation is
possible.
Locations impacted include...
Sullivan, Shelburn, Farmersburg, Dugger, Hymera, Carlisle, Merom,
Turtle Creek Reservoir, Graysville, and Paxton.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 3910 8762 3926 8743 3926 8727 3923 8724
3905 8724 3890 8752 3891 8753 3892 8753
3896 8751 3897 8753 3899 8758 3899 8756
3900 8758 3903 8757 3904 8758 3906 8757
3908 8760 3909 8762
TIME...MOT...LOC 1423Z 228DEG 33KT 3899 8760
MAX HAIL SIZE...0.75 IN
MAX WIND GUST...40 MPH
WhiteSpecial Weather Statement
National Weather Service Indianapolis IN
1055 AM EDT Sun May 26 2024
INZ052-053-060-061-067-068-261530-
Daviess IN-Knox IN-Clay IN-Owen IN-Greene IN-Sullivan IN-
1055 AM EDT Sun May 26 2024
...Strong thunderstorms will impact portions of southeastern
Sullivan, northeastern Knox, south central Clay, southwestern Owen,
western Greene and northwestern Daviess Counties through 1130 AM EDT
...
At 1054 AM EDT, Doppler radar was tracking strong thunderstorms along
a line extending from 6 miles east of Sullivan to 14 miles southwest
of Linton to near Russellville. Movement was northeast at 35 mph.
HAZARD...Wind gusts of 50 to 55 mph and half inch hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor hail damage to vegetation is
possible.
Locations impacted include...
Linton, Bloomfield, Bicknell, Jasonville, Worthington, Dugger, Lyons,
Elnora, Bruceville, Plainville, Sandborn, Edwardsport, Switz City,
Newberry, Freelandville, Pleasantville, and Vicksburg.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 3926 8694 3908 8687 3881 8712 3869 8745
3884 8737 3912 8734
TIME...MOT...LOC 1454Z 238DEG 31KT 3908 8730 3887 8731 3878 8747
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...55 MPH
WhiteSpecial Weather Statement
National Weather Service Indianapolis IN
1101 AM EDT Sun May 26 2024
INZ067-068-261545-
Daviess IN-Knox IN-
1101 AM EDT Sun May 26 2024
...Strong thunderstorms will impact portions of Knox and Daviess
Counties through 1145 AM EDT...
At 1100 AM EDT, Doppler radar was tracking strong thunderstorms along
a line extending from near St. Francisville to 9 miles southeast of
Vincennes to near Petersburg. Movement was northeast at 40 mph.
HAZARD...Wind gusts of 50 to 55 mph and half inch hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor hail damage to vegetation is
possible.
Locations impacted include...
Vincennes, Washington, Bicknell, Odon, Elnora, Monroe City,
Wheatland, Bruceville, Plainville, Sandborn, Montgomery, Edwardsport,
Freelandville, and Vincennes University.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 3859 8764 3859 8761 3861 8763 3867 8757
3869 8753 3875 8750 3890 8737 3890 8710
3881 8693 3852 8708 3854 8711 3852 8715
3855 8720 3854 8725 3851 8730 3854 8735
3854 8737 3852 8736 3854 8740 3856 8765
TIME...MOT...LOC 1500Z 209DEG 36KT 3859 8756 3858 8738 3848 8720
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...55 MPH
WhiteThe Indianapolis radar (KIND), 100 km away, was scanning. The volume nearest the first event began at 15:06 UTC.
6 thunderstorm wind, 1 hail, 1 tornado. Local standard time, as filed.
Several trees uprooted, a couple snapped, some power lines down from trees, and a little structural damage mainly from trees falling on homes caused by thunderstorm wind gusts.
The tornado with peak winds of 112 mph began near Decker where tree damage was found near the starting point. At the start, funnel clouds were jumping as most|of the damage was confined to the trees while houses remained|undamaged. The tornado quickly strengthened in producing low end|EF2 damage about a half mile east of Decker where a pole barn was|destroyed with debris found over a mile east of the original|damage location. In that same lot, a school bus was picked up and|moved about 20 yards away.
A sporadic damage path continued for about 2.5 miles northeast of|Decker with EF1 damage to mainly trees and one other small barn.|The sporadic damage path persisted through rural portions of|southern Knox County with EF0 tree and power line damage. About 3|miles southwest of Monroe City, the tornado hit another garage|structure, pushing in its bolted doors and causing the structure|to collapse. Debris from that structure was thrown about a mile|northeastward into a field, with drone footage capturing|circulations carved in the ground in that field. There were likely|a few circulations associated with the main tornado as additional|tree damage was found on the north side of this same property,|with no damage in between, leaving the house unaffected.
The tornado continued on its northeast path through southern Knox|County about a mile south of Monroe City, causing EF0 damage to|trees. The tornado lifted in rural portions of southeast Knox|County just prior to the Knox/Daviess County line.
Tree downed by thunderstorm wind gusts onto a house.
Power outages caused by thunderstorm wind gusts.
Straight line wind damage to trees was observed through eastern Daviess County. There was a localized area of more intense damage southwest of Washington.
Widespread tree damage from thunderstorm wind gusts occurred around West|Boggs Lake north of Loogootee where hundreds of trees were downed.
A large metal warehouse building sustained damage as thunderstorm wind entered|the structure under an awning on the south side of the building. Nearby tree damage was also noted.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Indiana in 2024Every state in 2024This day in weather historyThe tornado archive for Indiana, 2024Warnings in Indiana, May 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: 1169858, 1169859, 1171255, 1169861, 1169860, 1171256, 1171258, 1171259.