Alert archive / Kentucky / Mesoscale Discussions in 2018

Mesoscale Discussion 1101

July 20, 20186 states

The Storm Prediction Center issued this mesoscale discussion at Jul 20, 2018, 12:58 PM CDT for 6 states. It was in force for 62 min.

The area

The outline as issued.

The facts

Issued
Jul 20, 2018, 12:58 PM CDT (17:58 UTC)
Expired
Jul 20, 2018, 2:00 PM CDT
In force
62 min
Issued by
the Storm Prediction Center
Chance of a watch
80%
All 54 counties

Clay County, AR, Alexander County, IL, Gallatin County, IL, Hardin County, IL, Johnson County, IL, Massac County, IL, Pope County, IL, Pulaski County, IL, Saline County, IL, Union County, IL, Williamson County, IL, Vanderburgh County, IN, Ballard County, KY, Caldwell County, KY, Calloway County, KY, Carlisle County, KY, Christian County, KY, Crittenden County, KY, Daviess County, KY, Fulton County, KY, Graves County, KY, Hancock County, KY, Henderson County, KY, Hickman County, KY, Hopkins County, KY, Livingston County, KY, Lyon County, KY, Marshall County, KY, McCracken County, KY, McLean County, KY, Muhlenberg County, KY, Ohio County, KY, Todd County, KY, Trigg County, KY, Union County, KY, Webster County, KY, Bollinger County, MO, Butler County, MO, Cape Girardeau County, MO, Dunklin County, MO, Mississippi County, MO, New Madrid County, MO, Pemiscot County, MO, Ripley County, MO, Scott County, MO, Stoddard County, MO, Wayne County, MO, Henry County, TN, Houston County, TN, Lake County, TN, Montgomery County, TN, Obion County, TN, Stewart County, TN, Weakley County, TN

The radar

The Paducah radar (KPAH), 42 km from the middle of the area, began a volume at 17:59 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.

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Nashville Metro, TN (KBNA), launched 12:00Z, 6.0 hours before the alert went out and 256 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, Nashville Metro, TN at 12:00Z on 2018-07-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 918 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, Nashville Metro, TN at 12:00Z on 2018-07-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 123 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
918 J/kg
Mixed-layer CIN
-46 J/kg
Mixed-layer LCL
766 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
123 m²/s²
0-3 km storm-relative helicity
206 m²/s²
Significant tornado parameter
0.7
Supercell composite
5.7

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 19, 7:07 PM CDTSevere Thunderstorm WatchSPCBaxter, Boone, Carroll, Cleburne, Fulton, Independence and 10 more3 hr
Jul 19, 8:02 PM CDTMesoscale DiscussionSPCArkansas, Baxter, Clark, Cleburne, Cleveland, Conway and 40 more118 min
Jul 19, 8:54 PM CDTSevere Thunderstorm WatchSPCArkansas, Bradley, Calhoun, Clark, Clay, Cleveland and 35 more114 min
Jul 19, 11:21 PM CDTMesoscale DiscussionSPCChicot, Desha, Phillips114 min
Jul 20, 9:25 AM CDTMesoscale DiscussionSPCArkansas, Cleburne, Crittenden, Cross, Faulkner, Independence and 13 more2 hr
Jul 20, 3:46 PM CDTMesoscale DiscussionSPCBaxter, Boone, Fulton, Izard, Marion, Randolph and 2 more59 min
Jul 20, 3:58 PM CDTSevere Thunderstorm WatchSPCBaxter, Clay, Craighead, Cross, Fulton, Greene and 8 more6 hr
Jul 20, 5:54 PM CDTMesoscale DiscussionSPCCrittenden, Lee, Phillips, St. Francis3 hr
Jul 20, 6:22 PM CDTTornado WatchSPCCrittenden, Lee, Mississippi, Phillips, St. Francis8 hr
Jul 19, 9:36 PM CDTMesoscale DiscussionSPCAdams, Bond, Brown, Calhoun, Cass, Christian and 23 more54 min
Jul 19, 11:43 PM CDTMesoscale DiscussionSPCBond, Clay, Clinton, Cumberland, Edwards, Effingham and 13 more92 min
Jul 20, 12:19 PM CDTMesoscale DiscussionSPCBartholomew, Clark, Crawford, Dearborn, Decatur, Fayette and 15 more56 min
Jul 20, 12:37 PM CDTTornado WatchSPCBartholomew, Clark, Crawford, Dearborn, Decatur, Dubois and 18 more7 hr
Jul 20, 12:43 PM CDTMesoscale DiscussionSPCAdams, Allen, Blackford, Carroll, Cass, DeKalb and 16 more92 min
Jul 20, 1:12 PM CDTTornado WatchSPCAdams, Allen, Blackford, DeKalb, Elkhart, Grant and 10 more3 hr
Jul 20, 2:43 PM CDTMesoscale DiscussionSPCClark, Crawford, Dearborn, Decatur, Floyd, Franklin and 10 more62 min
Jul 20, 2:59 PM CDTMesoscale DiscussionSPCAdams, Allen, Blackford, DeKalb, Delaware, Jay and 2 more61 min
Jul 20, 5:37 PM CDTMesoscale DiscussionSPCBartholomew, Brown, Clark, Crawford, Dearborn, Decatur and 22 more53 min
Jul 20, 11:17 AM CDTMesoscale DiscussionSPCButler, Caldwell, Calloway, Christian, Crittenden, Daviess and 11 more58 min
Jul 20, 3:16 PM CDTSevere Thunderstorm WatchSPCBath, Bell, Boyd, Breathitt, Carter, Clay and 31 more6 hr
Jul 20, 6:24 PM CDTMesoscale DiscussionSPCBath, Bell, Boyd, Breathitt, Carter, Clark and 33 more96 min

Nearby

Mesoscale Discussions in Kentucky, 2018Mesoscale Discussions in Missouri, 2018Mesoscale Discussions in Illinois, 2018Every mesoscale discussion 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.