A band of moderate to heavy rainfall moved northeast over portions of central Indiana influenced by a warm front lifting northeast during the afternoon of August the 20th. A more intense portion of the band moved over Carroll County producing a single wind damage report.
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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.
A band of moderate to heavy rainfall moved northeast over portions of central Indiana influenced by a warm front lifting northeast during the afternoon of August the 20th. A more intense portion of the band moved over Carroll County producing a single wind damage report.
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 20, 12:35 PM EST, 22 minutes earlier.
Area Forecast Discussion National Weather Service Indianapolis IN 135 PM EDT Mon Aug 20 2018 .UPDATE... The AVIATION Section has been updated below. && .SYNOPSIS... Issued at 310 AM EDT Mon Aug 20 2018 A low pressure system will bring showers and some thunderstorms to central Indiana today & Tuesday. High pressure will then bring dry and cooler conditions mid-week, but rain chances will return to parts of the area for the weekend as warm and humid conditions return. && .NEAR TERM /Rest of Today/... Issued at 945 AM EDT Mon Aug 20 2018 With models handling the morning convection very poorly, had to make fail significant changes to late morning and early afternoon POPs. The convection across Illinois this morning fell apart as it approached the IL/IN boundary. Thus, dropped POPs across the SE portions of the state. Skies will continue to be mostly cloudy to cloudy today with the best chances for widespread rain and thunderstorms later this evening. Relevant portions of previous discussion follows... Isentropic lift will increase this morning ahead of a warm front associated with the low pressure system to the west. 850mb flow will increase and will pump more moisture into the area. The next round of forcing looks to remain just west of the area before 00Z, so will hold off on higher PoPs until the Tonight period. A decent amount of uncertainty exists on how much if any clearing occurs in the warm sector this afternoon. This will have an impact on high tempertures as well as how much instability builds. This leads to lower confidence in the threat for severe storms today. The Storm Prediction Center's Marginal Risk for much of the area looks reasonable given this setup. Precipitable water values will be high today, so locally heavy rain will be a threat as well. Given the uncertainty in cloud cover this afternoon, stuck with the model blend for high temperatures. && .SHORT TERM...(Tonight through Wednesday night) Issued at 310 AM EDT Mon Aug 20 2018 Models are close enough that the model blend initialization was accepted for most items. Another round of forcing moves in this evening and will likely generate another band of convection. Will go likely PoPs across the forecast area as this forcing works its way east into the early overnight hours. The actual cold front moves in late tonight, and this could bring more convection. Thus will continue with likely PoPs for much of the area overnight, diminishing late. As mentioned in the near term section, the amount of instability will be in question this evening. If enough builds, severe storms will remain possible this evening, mainly across the western half of the area. Locally heavy rain will remain a threat with the high moisture content of the atmosphere. An upper trough will remain across the area on Tuesday, so continued with mainly chance PoPs across the area. Kept some lingering shower chances across parts of the area Tuesday night as the system exits. High pressure will then build in and provide dry and cooler conditions Wednesday. && .LONG TERM /Thursday through Sunday Night/... Issued at 335 AM EDT Mon Aug 20 2018 High pressure centered over the Lower Midwest will keep conditions dry from Thursday through Friday morning, which is a little longer than previous model runs. Then shower and thunderstorm chances will increase from the northwest on Friday afternoon as an upper low enters the Upper Midwest. The highest chances for showers and thunderstorms will be on Friday night when forcing is the best with this disturbance. After that, just low chances for periodic showers and thunderstorms can be expected for the remainder of the weekend as weak waves rotate around a ridge of high pressure to the south. Meanwhile, temperatures through the period will start out below normal for Thursday and Friday, increasing back into the mid 80s to upper 80s by Saturday and Sunday. Overnight lows in the mid to upper 50s on Thursday night will also rebound back into the 60s through the end of the extended period. && .AVIATION /Discussion for 201800z TAFs/... Issued at 128 PM EDT Mon Aug 20 2018 Brief MVFR with current showers and storms moving NE through TAF sites becomes VFR in warm sector as winds swing from SE to south and get a bit gusty. Widely scattered convection in warm sector into this evening dies by sunset. A line of showers and storms just now developing in SC MO will expand and impact the TAF sites between 210400z and 210900z. Once this line passes through decks lower to MVFR then IFR by 210900z most areas before eventually rising back to MVFR by midday Tuesday. Winds will become south at or above 10 knots and somewhat gusty this afternoon as peaks of sun mix down stronger winds from aloft. Stabilization by sundown will end gustiness and drop wind speeds below 10 knots as south winds become southwest then west. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && SYNOPSIS...50 NEAR TERM...50/White SHORT TERM...50 LONG TERM....TDUD AVIATION...Tucek
Hazardous Weather Outlook National Weather Service Indianapolis IN 413 AM EDT Mon Aug 20 2018 INZ021-028>031-035>049-051>057-060>065-067>072-210815- 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 Lafayette, Frankfort, Kokomo, Crawfordsville, Anderson, Muncie, Indianapolis, Terre Haute, Shelbyville, Bloomington, Columbus, Vincennes, Bedford, and Seymour 413 AM EDT Mon Aug 20 2018 This hazardous weather outlook is for central Indiana. .DAY ONE...Today and Tonight. Outlook: Scattered thunderstorms will be around. Isolated strong to severe storms are possible, mainly west of US 31. Hazards: Damaging winds, heavy rain, localized flooding, and lightning. Timing: Highest chances for severe storms will be this afternoon and evening. Heavy rain and lightning are possible any time. Discussion: A low pressure system will bring showers and some thunderstorms to central Indiana today and tonight. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. Outlook: Thunderstorms are possible Tuesday. More storms are possible across all or parts of central Indiana from Friday night through Sunday. Lightning is a threat with any thunderstorm. Discussion: A cold front will move through on Tuesday. Warm and humid air will return for the weekend, bringing the threat for some thunderstorms with it. .SPOTTER INFORMATION STATEMENT... Spotter activation cannot be ruled out this afternoon and evening. Spotters are encouraged to report any heavy rain, flooding, or strong winds observed. && More information, along with other weather, hydrological and climate information can be found at http://weather.gov/ind
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1159 AM EDT MON AUG 20 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1158 AM HEAVY RAIN 2 SW TURKEY RUN STATE P 39.87N 87.25W
08/20/2018 M0.75 INCH PARKE IN TRAINED SPOTTER
THE DURATION OF THE HEAVY RAIN EVENT WAS 5
MINUTES.
&&
AWPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
110 PM EDT MON AUG 20 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0103 PM HEAVY RAIN CRAWFORDSVILLE 40.04N 86.90W
08/20/2018 M1.62 INCH MONTGOMERY IN EMERGENCY MNGR
THE DURATION OF THE HEAVY RAIN EVENT WAS 15
MINUTES.
&&
AWSpecial Weather Statement National Weather Service Indianapolis IN 116 PM EDT MON AUG 20 2018 INZ029-030-036-037-201745- Montgomery IN-Clinton IN-Boone IN-Tippecanoe IN- 116 PM EDT MON AUG 20 2018 ...SPECIAL WEATHER STATEMENT... At 113 PM EDT, Doppler radar was tracking a strong thunderstorm 7 miles southwest of Frankfort, moving northeast at 30 mph. Winds in excess of 30 mph will be possible with this storm. Torrential rainfall is also occurring. Locations impacted include... Frankfort, Rossville, Thorntown, Mulberry, Colfax, Clarks Hill and Michigantown. PRECAUTIONARY/PREPAREDNESS ACTIONS... Very heavy rainfall is the main threat with this storm. Rainfall rates up to 4 inches per hour and rainfall totals approaching 2 inches in some areas may lead to localized flooding. Do not drive your vehicle through flooded roadways. && LAT...LON 4037 8624 4002 8663 4019 8682 4043 8667 TIME...MOT...LOC 1713Z 205DEG 30KT 4020 8661 DRT
Special Weather Statement
National Weather Service Indianapolis IN
145 PM EDT MON AUG 20 2018
INZ021-030-031-201830-
Howard IN-Clinton IN-Carroll IN-
145 PM EDT MON AUG 20 2018
...SIGNIFICANT WEATHER ADVISORY FOR EASTERN CARROLL...CLINTON AND
WESTERN HOWARD COUNTIES UNTIL 230 PM EDT...
At 145 PM EDT, Doppler radar was tracking a strong thunderstorm near
Frankfort, moving northeast at 40 mph.
Wind gusts of 50 to 55 mph will be possible with this storm.
Locations impacted include...
Kokomo, Frankfort, Flora, Rossville, Russiaville, Camden, Burlington
and Michigantown.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Very heavy rainfall is the main threat with this storm. Rainfall
rates up to 4 inches per hour and rainfall totals approaching 2
inches in some areas may lead to localized flooding. Do not drive
your vehicle through flooded roadways.
&&
LAT...LON 4056 8637 4056 8604 4040 8618 4040 8624
4032 8624 4020 8633 4030 8665 4069 8652
4069 8637
TIME...MOT...LOC 1745Z 206DEG 34KT 4032 8640
AW/DTThe Indianapolis radar (KIND), 81 km away, was scanning. The volume nearest the first event began at 17:54 UTC.
1 thunderstorm wind. Local standard time, as filed.
A barn roof was torn off, multiple large trees were downed, and a power line was down due to damaging thunderstorm wind gusts.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Indiana in 2018Every state in 2018This day in weather historyWarnings in Indiana, August 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: 783086.