Numerous pulse thunderstorms crossed central Indiana from west to east from pre-dawn to mid-morning hours. Despite several strong storms, a stable boundary layer prevented higher wind gusts from mixing down to the surface while a high freezing level melted larger hail aloft before it could reach the ground.
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.
Numerous pulse thunderstorms crossed central Indiana from west to east from pre-dawn to mid-morning hours. Despite several strong storms, a stable boundary layer prevented higher wind gusts from mixing down to the surface while a high freezing level melted larger hail aloft before it could reach the ground. One marginally severe cell did, however, track southeastward across Johnson and Bartholomew Counties around 900 AM EDT.
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 Aug 12, 7:25 AM EST, 12 minutes earlier.
Area Forecast Discussion National Weather Service Indianapolis IN 825 AM EDT Sat Aug 12 2023 .Mesoscale Update... Issued at 823 AM EDT Sat Aug 12 2023 Morning convection continues across Central Indiana and is moving E- SE around 25 to 30 MPH. This area of convection continues to follow the leading edge of a theta-e gradient helping support the weakly forced thunderstorms. These thunderstorms are being fueled by this moderately moist air mass along with 7.0 C/km mid level lapse rates leading to around 1000 J/kg of MLCAPE. VWP wind profiles show weak to moderate 0-3km shear enough for semi- sustained updrafts and Organized clusters; reaching storm tops of 30-35 kft. This along with a relative dry 850-750mb layer could create breif downbursts of 40-45 mph. A few of the cells have sustained more porlonged cores capable of producing 0.5 to 0.75 in hail but there are still minimal signs that hail 1" or greater is possible, likely due to a saturated near surface layer and a freezing level of 12 kft. With all that said, all storms are expected to remain strong but under severe criteria, and should continue through the morning hours until gradient induced forncing in reduced and moved eastward. With the storm motion under 30kts, along with rain rates of 2-4 inches/hr minor areal flooding and ponding on roadways is possible, especially in areas that receive multiple rounds of thunderstorms. && .Short Term...(Today and tonight) Issued at 303 AM EDT Sat Aug 12 2023 Top concerns for Saturday... - Temporal and Spatial extent of convection this morning - Strength of convection that does develop and potential for severe - Potential for brief heavy downpours from slow moving convection Will start with early this morning... Quiet conditions across Central Indiana early this morning, with not much of a T/Td spread across the state. A few locations have begun to observe fog develop, but this still appears to be limited to areas of the Wabash Valley and points southwest of Indy metro. VAD profile from KIND still showing some movement to air above the deck at 1kft agl, which does appear to be enough friction inhibiting fog from becoming more widespread. What fog does develop, should dissipate shortly after daybreak. Satellite imagery early this morning also showing the upstream complex that has developed over far Northern Missouri and Southeast Iowa, with cloud shield beginning to flirt with eastern Illinois as of 7Z. The question is whether any of this early morning convection will drift east into Central Indiana around daybreak. The main theta- e axis continues to be focused well to the southwest of the forecast area, and has been the case of late this seems to be the best zone to be following the track of convective elements due to the instability associated. The gradient of higher theta-e is on the doorsteps to the far Southwest Indiana counties, and some indications are present that advection of this axis and gradient could lift northeast a touch more this morning. But likely not until later in the morning or closer to midday. Midday through Afternoon... Late last evening an area of convection was decaying as it moved into Northern Illinois, but this boundary still exists. The expectation is that the boundary will continue to drift south this morning, and with the instability gradient beginning to grow stronger, some differential heating will help to engage parcels by mid/late morning and pop some convection. As was eluded to in the first few bullet points, the challenge remains on the temporal and spatial side of this development. Cloud cover from the earlier mentioned complex nearing Eastern Illinois could also pose an impact to the placement, as clouds will create a modified environment on the north/south due to differential heating that would take place. The challenge along with what is outlined above is also on how far northeast the theta-e axis/gradient drifts north and forward speed to the boundary sliding south. Trends have suggested that these two parameters may not gel completely and perhaps remain displaced until later in the day/evening. Focusing more robust convective elements to the far southwest and southeast of the Indy metro. Have taken a conservative approach and held onto the midday solution, but confidence in strong thunderstorm development does appear to be minimal. But as was mentioned prior, the atmosphere can easily be modified due to differential elements. The moisture rich environment adds yet another element of concern to slow moving storms and potential for warm rain processes to introduce some flooding potential. But again confidence of this is low at this time. Tonight...Longwave flow does favor a progressive push to the afternoon/evening convection/clouds with the boundary allowing a light northerly surface conditions late tonight. So expect clouds to dissipate along with precip chances and result in a dry overnight. Temps should be able to radiate lower than has been the case the last few nights from the northerly flow into the low/mid 60s. && .Long Term...(Sunday through Friday) Issued at 303 AM EDT Sat Aug 12 2023 Sunday and Sunday Evening... Sunday should start quiet with typical late summer-type weather as light southwesterly winds hold rather humid conditions and mostly sunny skies allow insolation to easily boost temperatures into the low to mid-80s. Convection chances will increase for the afternoon, when scattered to numerous showers/t-storms may slide west to east across mainly southern counties. Adequate parameters will include low/moderate vertical wind shear and CAPE climbing to the 1000-1500 J/kg range for at least a few hours in the afternoon...although this may be somewhat offset by decreasing mid-level lapse rates through peak heating. Suspect any afternoon cells die off with the falling sun before a more organized rain threat later Sunday night. Sunday's high temperatures in the 82-86F range may be the highest for central Indiana until the following weekend. Late Sunday night through Wednesday... Guidance continues to show a deeper upper trough crossing the Midwest through the early workweek...promoting surface low pressure and the corresponding baroclinic zone passing over Indiana in the Sunday night-Monday night timeframe. Opportunities for organized, if not widespread precipitation should follow the approaching system into early Monday...as well as convective potential later Monday from what could be a solid combination of upper forcing and daytime heating. Amid this system's moderate to higher levels of deep shear, it appears instability will be quite limited with the first round of showers...yet both CAPE and mid-level lapse rates should be adequate later Monday to promote strong/severe cells. Any risk here is conditional on position and timing of the system's low level features/boundaries as well as how much skies clear between the two areas of precipitation...however, at least moderate confidence in the associated cold front lagging enough to encourage convection over the CWA's southeastern half Monday afternoon. A noticeable transition to more early autumn type conditions will be felt into the mid-week as the belly of the H500 trough crosses Indiana around the Tuesday timeframe. Cool air advection will be the rule with broad surface high pressure plunging to the southeast over the central Plains...with the corresponding forecast H850 20*C contour extending from International Falls, MN to the Louisiana Gulf coast Tuesday night. Tuesday may be a somewhat dreary day despite lower humidity as the system's warm frontal occlusion may drag near the region holding low cloud and scattered light precipitation. Nevertheless expect fair and cool conditions to take over for the Tuesday night-Wednesday time frame under an unseasonably dry column and slackening northwest to westerly surface flow. After a moderately humid and seasonable Sunday night...below normal temperatures are expected through this period, first under greater cloud cover and reduced heights...and then with at least 1-2 overnights in the 50s, likely starting Tuesday night on the heels of the departing system. Thursday and Friday... Models are still debating how the synoptic pattern will trend through the late workweek...with large run to run variations offering solutions from a somewhat strong front bringing convective chances on Thursday...to a retracting upper zonal flow into southern Canada allowing the hot subtropical ridge to build north and east over most of the CONUS. Imagine at the very least decent return flow will bring seasonable deep moisture and 80s on Thursday...although rain chances are questionable with even some of the more amplified ensemble solutions showing low QPF. Stuck with the Blends' slightly below normal readings for these two days, with a low probability of Friday trending much warmer in subsequent updates. && .Aviation...(12Z TAF Issuance) Issued at 702 AM EDT Sat Aug 12 2023 Impacts: - Morning convection impacting airfields - Thunderstorm chances increase after daybreak through afternoon. Discussion: Some scattered showers and thunderstorms have been sliding east/southeast across Central Indiana early this morning and impacting some of the airfields. Expect brief reduction to MVFR CIGs and perhaps due to any downpours that VSBYs could also drop to around 3-4sm, before returning back to P6SM. Then the challenge is on timing and placement as several of the latest hi-res simulations are fluctuating in their placement. So confidence remains low on those items, but still anticipate the best timing to be after 16z and likely persist thru 19-20Z. Then winds will shift to westerly and eventually northwesterly. && .IND WATCHES/WARNINGS/ADVISORIES... None. && Mesoscale...Updike Short Term...Beach Long Term...AGM Aviation...Beach
Hazardous Weather Outlook National Weather Service Indianapolis IN 342 AM EDT Sat Aug 12 2023 INZ021-028>031-035>049-051>057-060>065-067>072-130745- 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 342 AM EDT Sat Aug 12 2023 This hazardous weather outlook is for central Indiana. .DAY ONE...Today and Tonight. Isolated to scattered thunderstorms early this morning mainly west of Kokomo to Indianapolis. A strong storm or two cannot be ruled out, with gusty winds possible, but lightning, heavy rain, and localized flooding will be the primary hazards. Additional scattered thunderstorms will be possible midday through afternoon. A few of which could be strong to severe this afternoon. Any thunderstorm will be capable of heavy rainfall and lightning. Heavy rainfall may lead to localized flooding. Storm motion will generally be from the west at 30-40 MPH. .DAYS TWO THROUGH SEVEN...Sunday through Friday. Scattered thunderstorms will be possible Sunday afternoon into Monday. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed this morning and again this afternoon. && More information, along with other weather, hydrological and climate information can be found at http://weather.gov/ind
Special Weather Statement
National Weather Service Indianapolis IN
733 AM EDT Sat Aug 12 2023
INZ060-061-067-068-121200-
Daviess IN-Knox IN-Greene IN-Sullivan IN-
733 AM EDT Sat Aug 12 2023
...A strong thunderstorm will impact portions of southeastern
Sullivan, northeastern Knox, southwestern Greene and northwestern
Daviess Counties through 800 AM EDT...
At 733 AM EDT, Doppler radar was tracking a strong thunderstorm 11
miles south of Sullivan, or 20 miles northeast of Vincennes, moving
east at 25 mph.
HAZARD...Winds in excess of 40 mph.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects.
This storm will remain over mainly rural areas of southeastern
Sullivan, northeastern Knox, southwestern Greene and northwestern
Daviess Counties, including the following locations... Lyons,
Newberry, Edwardsport, Elnora, Oaktown, Pleasantville, Carlisle,
Freelandville, Paxton, and Plainville.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 3886 8745 3904 8739 3900 8694 3873 8703
TIME...MOT...LOC 1133Z 284DEG 22KT 3894 8734
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH
MKSpecial Weather Statement
National Weather Service Indianapolis IN
745 AM EDT Sat Aug 12 2023
INZ046-047-054-055-121215-
Johnson IN-Morgan IN-Hendricks IN-Marion IN-
745 AM EDT Sat Aug 12 2023
...A strong thunderstorm will impact portions of northeastern Morgan,
western Johnson, southeastern Hendricks and southwestern Marion
Counties through 815 AM EDT...
At 745 AM EDT, Doppler radar was tracking a strong thunderstorm near
Mooresville, or 22 miles southwest of Indianapolis, moving east at 25
mph.
HAZARD...Winds in excess of 30 mph and half inch hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
This strong thunderstorm will be near...
Mooresville around 750 AM EDT.
This includes Interstate 70 between mile markers 57 and 62.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
&&
LAT...LON 3950 8657 3963 8652 3965 8610 3938 8614
TIME...MOT...LOC 1145Z 276DEG 20KT 3955 8646
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...30 MPH
MKSpecial Weather Statement
National Weather Service Indianapolis IN
748 AM EDT Sat Aug 12 2023
INZ044-045-051-052-121215-
Clay IN-Putnam IN-Parke IN-Vigo IN-
748 AM EDT Sat Aug 12 2023
...A strong thunderstorm will impact portions of northeastern Vigo,
north central Clay, southeastern Parke and southwestern Putnam
Counties through 815 AM EDT...
At 748 AM EDT, Doppler radar was tracking a strong thunderstorm 8
miles northwest of Brazil, or 14 miles northeast of Terre Haute,
moving east at 30 mph.
HAZARD...Winds in excess of 40 mph.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects.
This storm will remain over mainly rural areas of northeastern Vigo,
north central Clay, southeastern Parke and southwestern Putnam
Counties, including the following locations... Bridgeton, Reelsville,
Lena, Cloverdale, Carbon, Rosedale, and Harmony.
This includes Interstate 70 between mile markers 34 and 41.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
&&
LAT...LON 3959 8729 3970 8726 3974 8677 3947 8680
TIME...MOT...LOC 1148Z 274DEG 27KT 3963 8720
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH
MKSpecial Weather Statement
National Weather Service Indianapolis IN
804 AM EDT Sat Aug 12 2023
INZ061-067>070-121230-
Daviess IN-Knox IN-Martin IN-Lawrence IN-Greene IN-
804 AM EDT Sat Aug 12 2023
...A strong thunderstorm will impact portions of northeastern Knox,
Martin, southern Greene, western Lawrence and northern Daviess
Counties through 830 AM EDT...
At 804 AM EDT, Doppler radar was tracking a strong thunderstorm 10
miles southwest of Bloomfield, or 29 miles west of Bedford, moving
east at 35 mph.
HAZARD...Winds in excess of 30 mph and half inch hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
This storm will remain over mainly rural areas of northeastern Knox,
Martin, southern Greene, western Lawrence and northern Daviess
Counties, including the following locations... Newberry, Loogootee,
West Boggs Lake, Indian Springs, Huron, Crane, Burns City, Odon,
Williams, and Elnora.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
&&
LAT...LON 3872 8723 3898 8712 3900 8668 3899 8668
3899 8657 3869 8667 3869 8668 3864 8668
TIME...MOT...LOC 1204Z 273DEG 31KT 3889 8703
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...30 MPH
MKSpecial Weather Statement
National Weather Service Indianapolis IN
815 AM EDT Sat Aug 12 2023
INZ067>069-121245-
Daviess IN-Knox IN-Martin IN-
815 AM EDT Sat Aug 12 2023
...A strong thunderstorm will impact portions of east central Knox,
southern Martin and southern Daviess Counties through 845 AM EDT...
At 815 AM EDT, Doppler radar was tracking a strong thunderstorm 7
miles east of Washington, or 17 miles northeast of Petersburg, moving
east at 35 mph.
HAZARD...Winds in excess of 30 mph and half inch hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
This strong thunderstorm will be near...
Shoals around 830 AM EDT.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
&&
LAT...LON 3850 8696 3850 8698 3851 8700 3850 8706
3854 8711 3853 8714 3852 8715 3855 8718
3855 8720 3854 8722 3854 8725 3853 8725
3855 8733 3871 8723 3866 8668 3853 8668
3853 8683 3849 8688 3851 8693 3849 8695
TIME...MOT...LOC 1215Z 273DEG 31KT 3867 8704
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...30 MPH
MKSpecial Weather Statement
National Weather Service Indianapolis IN
820 AM EDT Sat Aug 12 2023
INZ054-055-063-121300-
Johnson IN-Brown IN-Morgan IN-
820 AM EDT Sat Aug 12 2023
...A strong thunderstorm will impact portions of eastern Morgan,
southern Johnson and northern Brown Counties through 900 AM EDT...
At 820 AM EDT, Doppler radar was tracking a strong thunderstorm 7
miles northeast of Martinsville, or 22 miles south of Indianapolis,
moving southeast at 20 mph.
HAZARD...Winds in excess of 40 mph and half inch hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
This storm will remain over mainly rural areas of eastern Morgan,
southern Johnson and northern Brown Counties, including the following
locations... Mahalasville, Peoga, Morgantown, Waverly, Trafalgar,
Spearsville, Princes Lakes, Centerton, Brooklyn, and Bargersville.
This includes Interstate 65 between mile markers 87 and 90.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
&&
LAT...LON 3933 8638 3934 8638 3934 8640 3946 8657
3959 8632 3947 8596 3934 8607 3934 8608
3933 8608 3920 8620
TIME...MOT...LOC 1220Z 302DEG 16KT 3948 8630
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH
MKThe Indianapolis radar (KIND), 23 km away, was scanning. The volume nearest the first event began at 12:38 UTC.
1 thunderstorm wind, 1 hail. Local standard time, as filed.
Thunderstorm winds downed a few small to medium sized tree branches, while flattening an approximate one-third acre of soybean crop.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Indiana in 2023Every state in 2023This day in weather historyWarnings in Indiana, August 2023
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: 1107856, 1107855.