EF1 tornado, Millersburg, Kentucky, December 21, 2013

1. EF065 to 85 mph

   Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

2. EF186 to 110 mphthis tornado

   Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

3. EF2111 to 135 mph

   Considerable damage. Roofs torn off well-built houses, frame homes shifted on their foundations, mobile homes destroyed, large trees snapped or uprooted, cars lifted off the ground.

4. EF3136 to 165 mph

   Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

5. EF4166 to 200 mph

   Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

6. EF5over 200 mph

   Incredible damage. Strong frame houses swept off their foundations, car-sized missiles thrown more than 100 meters, steel-reinforced concrete badly damaged, high-rise buildings deformed.

7. Unrated

   The survey recorded a tornado but could not put a number on it, most often because it crossed open country and damaged nothing a rating can be read from.

Rating

EF1

Date

December 21, 2013

Touchdown

11:41 PM EST (04:41 UTC)

Lifted

11:45 PM EST (04:45 UTC)

On the ground

4 minutes

Path length

5.7 miles (9.2 km)

Path width

125 yards (114 m)

Deaths

0

Injuries

0

Property damage

$150,000

County

Bourbon County

Touchdown point

38.300, -84.248

Lift-off point

38.332, -84.150

Record number

1312212241-01

22 damage points were recorded along this path by NWS LMK, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 100 mph.

• tops of roof moved onto Highway 1842
• 2 barns destroyed, trees split. uprooted in a NE to SE direction
• 1469 Dutch Chapel Rd, significant roof damage, garage destroyed, damage scattered NE to ESE
• damage scattered to 1471 Dutch Chapel Rd, about 300 yards

Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.

A deep trough embedded within the southern stream of the jet combined with unseasonably rich moisture to bring widespread flooding and a regional severe weather outbreak to the Lower Ohio Valley during the afternoon and evening of December 21st. Heavy rains, on the order of 2 to locally as much as 3 inches, developed during the morning hours across southern Indiana and the Kentucky counties along the Ohio River. These heavy rains, augmented by a December record 1.7 inches of precipitable water, developed along a stationary front that lay along but just north of the Ohio River from Cairo, IL to Cincinnati. These early rains, combined with thunderstorms during the afternoon and early evening, brought areal and river flooding to north central Kentucky. ||By early afternoon, low pressure deepened as it moved northeast across central Illinois and northern Indiana. Rains ceased by mid-day as central Kentucky fell within the warm sector of the developing cyclone. Record high temperatures in the lower 70s arrived by early evening. A severe squall line developed by mid-afternoon from southern Illinois southwards along the Mississippi River. This line of storms, fueled by ample moisture and an exceptionally strong low level jet in excess of 50 kts, became severe as it moved across southern Indiana and central Kentucky during the evening hours. Three circulations within this line produced tornadoes across central Kentucky and the Bluegrass Region. For the Louisville weather office, these 3 December tornadoes were the first observed since 1971. This line also brought widespread damaging winds, especially to the Bluegrass Region and Hart and Barren Counties in Central Kentucky.

A survey confirmed that an EF-1 tornado was embedded within a severe squall line that brought widespread damage to northern Bourbon County. An area of concentrated damage was surveyed along Colville and Steele Ford Roads as well as Endicott Lane. Along these roads several large barns and outbuildings were either destroyed or heavily damaged. EF-1 damage was confirmed along Endicott Lane as some well-anchored barn footers were lifted up and thrown 75 yards. Several residents also reported a loud roar within torrential rain as the line of storms passed.

From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down.

The county was under a severe thunderstorm watch, issued at 02:22 UTC and running to 06:06 UTC.

Every warning and watch covering the touchdown point that day, from the Iowa Environmental Mesonet's archive of National Weather Service products. Lead time is measured from the issue of the warning in force to the touchdown time in the database, both of which were recorded to the minute by different people.

The Storm Prediction Center had this point in a Slight Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 00:46 UTC.

SPC's Day 1 convective outlook as it stood when the tornado began, read at the touchdown point. The same archive is on the radar archive.

The radiosonde launches on either side of the tornado, from the nearest station that was launching then, drawn and analyzed the way Storm Lab does: the same diagram, the same parcel and shear definitions SPC's mesoanalysis uses.

Mount Sterling (IOB), 34 km from the path, in the two hours either side.

From the Iowa Environmental Mesonet's archive of airport observations.

The Jackson,KY radar (KJKL), 112 km away, was scanning. The volume nearest the touchdown began at 04:39 UTC.

Open the radar archive at this moment, over the track

Reflectivity and velocity, decoded from the Level II archive in the browser. Volumes take a few seconds to open the first time.

Local storm reports within 60 km of the path, in the three hours either side.

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

The live radar over the trackEvery 2013 tornado in KentuckyEvery tornado in Kentucky since 1950Warnings in force in Kentucky nowThe forecast where you are

13 more were confirmed in the United States that day.

Ratings are the survey's, read off the damage rather than measured; the rating scale is above. Tornado counts rise through the record as reporting improved, so a year in the 1950s is not comparable with one today except for the strongest tornadoes, which were always noticed.

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.