Alert archive / Indiana / Tornado Watches in 2018

Tornado Watch 290

July 20, 201816 counties in Indiana; 5 counties in Michigan

The Storm Prediction Center issued this tornado watch at Jul 20, 2018, 2:12 PM EDT for 16 counties in Indiana; 5 counties in Michigan. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Jul 20, 2018, 2:12 PM EDT (18:12 UTC)
Expired
Jul 20, 2018, 5:17 PM EDT
In force
3 hr
Issued by
the Storm Prediction Center
Largest hail expected
1.5 in
Strongest gust expected
60 kt
All 21 counties

Adams County, IN, Allen County, IN, Blackford County, IN, DeKalb County, IN, Elkhart County, IN, Grant County, IN, Huntington County, IN, Jay County, IN, Kosciusko County, IN, LaGrange County, IN, Miami County, IN, Noble County, IN, Steuben County, IN, Wabash County, IN, Wells County, IN, Whitley County, IN, Branch County, MI, Cass County, MI, Kalamazoo County, MI, Saint Joseph County, MI, Van Buren County, MI

The radar

The Northern Indiana radar (KIWX), 27 km from the middle of the area, began a volume at 18:16 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
30%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
50%
One or more gusts of 65 knots or more
20%
Ten or more severe hail reports
50%
One or more hailstones of 2 inches or more
20%
Six or more combined severe hail and wind reports
80%

Warnings issued inside it

7 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Jul 20, 2:24 PM EDTSevere Thunderstorm WarningIWXElkhart, Kosciusko, LaGrange, Noble, Saint Joseph51 min
Jul 20, 2:36 PM EDTTornado WarningIWXKosciusko, Wabash, Whitley22 min
Jul 20, 3:00 PM EDTSevere Thunderstorm WarningIWXAllen, Huntington, Wabash, Whitley45 min
Jul 20, 3:11 PM EDTTornado WarningIWXHuntington, Wabash18 min
Jul 20, 3:40 PM EDTSevere Thunderstorm WarningIWXAdams, Blackford, Grant, Huntington, Jay, Wells50 min
Jul 20, 3:45 PM EDTTornado WarningIWXBlackford30 min
Jul 20, 4:07 PM EDTSevere Thunderstorm WarningIWXAdams, Allen, Wells38 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Detroit, MI (KDTX), launched 12:00Z, 6.2 hours before the alert went out and 215 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Detroit, MI at 12:00Z on 2018-07-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Detroit, MI at 12:00Z on 2018-07-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 151 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
2 J/kg
Mixed-layer CIN
-259 J/kg
Mixed-layer LCL
1262 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
151 m²/s²
0-3 km storm-relative helicity
162 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

872 
WWUS20 KWNS 201810
SEL0  
SPC WW 201810
INZ000-MIZ000-202200-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 290
NWS Storm Prediction Center Norman OK
215 PM EDT Fri Jul 20 2018

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Northern Indiana
  Southwest Lower Michigan

* Effective this Friday afternoon and evening from 215 PM until
  600 PM EDT.

* Primary threats include...
  A couple tornadoes possible
  Scattered damaging wind gusts to 70 mph possible
  Scattered large hail events to 1.5 inches in diameter possible

SUMMARY...A line of thunderstorms over northwest Indiana will spread
eastward across the watch area, with some potential for a tornado or
two, hail, and damaging wind gusts.

The tornado watch area is approximately along and 25 statute miles
east and west of a line from 5 miles west of Kalamazoo MI to 115
miles south of Kalamazoo MI. For a complete depiction of the watch
see the associated watch outline update (WOUS64 KWNS WOU0).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Tornado Watch means conditions are favorable for
tornadoes and severe thunderstorms in and close to the watch
area. Persons in these areas should be on the lookout for
threatening weather conditions and listen for later statements
and possible warnings.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 289...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 1.5 inches. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean
storm motion vector 22025.

...Hart

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 20, 12:43 AM EDTMesoscale DiscussionSPCGibson, Posey92 min
Jul 20, 1:19 PM EDTMesoscale DiscussionSPCBartholomew, Clark, Crawford, Dearborn, Decatur, Fayette and 15 more56 min
Jul 20, 1:37 PM EDTTornado WatchSPCBartholomew, Clark, Crawford, Dearborn, Decatur, Dubois and 18 more7 hr
Jul 20, 1:43 PM EDTMesoscale DiscussionSPCAdams, Allen, Blackford, Carroll, Cass, DeKalb and 16 more92 min
Jul 20, 1:58 PM EDTMesoscale DiscussionSPCVanderburgh62 min
Jul 20, 3:43 PM EDTMesoscale DiscussionSPCClark, Crawford, Dearborn, Decatur, Floyd, Franklin and 10 more62 min
Jul 20, 3:59 PM EDTMesoscale DiscussionSPCAdams, Allen, Blackford, DeKalb, Delaware, Jay and 2 more61 min
Jul 20, 6:37 PM EDTMesoscale DiscussionSPCBartholomew, Brown, Clark, Crawford, Dearborn, Decatur and 22 more53 min
Jul 20, 7:22 PM EDTTornado WatchSPCClark, Crawford, Dubois, Floyd, Gibson, Harrison and 10 more8 hr

Nearby

Tornado Watches in Indiana, 2018Tornado Watches in Michigan, 2018Every tornado watch in 2018

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.