Alert archive / Mississippi / Tornado Watches in 2018

Tornado Watch 44

April 13, 20187 counties in Arkansas; 9 parishes in Louisiana; 10 counties in Mississippi

The Storm Prediction Center issued this tornado watch at Apr 13, 2018, 7:22 PM CDT for 7 counties in Arkansas; 9 parishes in Louisiana; 10 counties in Mississippi. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Apr 13, 2018, 7:22 PM CDT (00:22 UTC)
Expired
Apr 13, 2018, 10:14 PM CDT
In force
3 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 26 counties

Arkansas County, AR, Ashley County, AR, Chicot County, AR, Desha County, AR, Drew County, AR, Lincoln County, AR, Monroe County, AR, Catahoula Parish, LA, Concordia Parish, LA, East Carroll Parish, LA, Franklin Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Richland Parish, LA, Tensas Parish, LA, West Carroll Parish, LA, Adams County, MS, Bolivar County, MS, Claiborne County, MS, Franklin County, MS, Issaquena County, MS, Jefferson County, MS, Sharkey County, MS, Sunflower County, MS, Warren County, MS, Washington County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 139 km from the middle of the area, began a volume at 00:25 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
60%
One or more EF2 to EF5 tornadoes
30%
Ten or more severe wind reports
80%
One or more gusts of 65 knots or more
20%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
95%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 13, 7:24 PM CDTTornado Warning Tornado observedJANMorehouse34 min
Apr 13, 7:49 PM CDTTornado WarningJANAshley24 min
Apr 13, 8:12 PM CDTSevere Thunderstorm WarningJANRichland48 min
Apr 13, 8:28 PM CDTTornado WarningJANRichland62 min
Apr 13, 8:35 PM CDTTornado WarningJANRichland55 min
Apr 13, 9:04 PM CDTTornado WarningJANMorehouse, Richland, West Carroll56 min
Apr 13, 9:59 PM CDTSevere Thunderstorm WarningJANAshley, Chicot46 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

Jackson, MS (KJAN), launched 00:00Z, 0.4 hours before the alert went out and 129 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, Jackson, MS at 00:00Z on 2018-04-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 92 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Jackson, MS at 00:00Z on 2018-04-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 94 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
92 J/kg
Mixed-layer CIN
-56 J/kg
Mixed-layer LCL
1418 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
94 m²/s²
0-3 km storm-relative helicity
158 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

154 
WWUS20 KWNS 140018
SEL4  
SPC WW 140018
ARZ000-LAZ000-MSZ000-140800-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 44
NWS Storm Prediction Center Norman OK
720 PM CDT Fri Apr 13 2018

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Southeast Arkansas
  Northeast Louisiana
  Western Mississippi

* Effective this Friday night and Saturday morning from 720 PM
  until 300 AM CDT.

* Primary threats include...
  A few tornadoes likely with a couple intense tornadoes possible
  Widespread damaging wind gusts to 70 mph likely
  Isolated very large hail events to 2 inches in diameter possible

SUMMARY...Scattered supercells with a history of producing tornadoes
will continue to move across northeast Louisiana into far southeast
Arkansas and eventually far western Mississippi this evening. More
numerous storm coverage is expected late this evening into the
overnight with a risk for tornadoes and wind damage continuing.

The tornado watch area is approximately along and 30 statute miles
east and west of a line from 40 miles northeast of Monticello AR to
15 miles south southwest of Natchez MS. For a complete depiction of
the watch see the associated watch outline update (WOUS64 KWNS
WOU4).

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 39...WW 40...WW 41...WW
42...WW 43...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 2 inches. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean
storm motion vector 20035.

...Guyer

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 13, 7:06 PM CDTMesoscale DiscussionSPCHoward, Montgomery, Yell24 min
Apr 13, 8:36 PM CDTMesoscale DiscussionSPCGarland, Howard, Pike54 min
Apr 13, 8:54 PM CDTMesoscale DiscussionSPCArkansas, Bradley, Calhoun, Clark, Clay, Cleburne and 47 more66 min
Apr 13, 9:53 PM CDTTornado WatchSPCArkansas, Baxter, Bradley, Calhoun, Clark, Cleburne and 37 more8 hr
Apr 13, 10:12 PM CDTTornado WatchSPCAshley, Chicot, Clay, Craighead, Crittenden, Cross and 8 more10 hr
Apr 14, 2:10 AM CDTMesoscale DiscussionSPCAshley, Bradley, Calhoun, Chicot, Desha, Drew and 3 more2 hr
Apr 14, 6:37 AM CDTMesoscale DiscussionSPCAscension, Assumption, East Baton Rouge, East Feliciana, Iberia, Iberville and 20 more83 min
Apr 14, 6:57 AM CDTTornado WatchSPCAscension, Assumption, East Baton Rouge, East Feliciana, Iberia, Iberville and 22 more7 hr
Apr 14, 4:35 AM CDTMesoscale DiscussionSPCAlcorn, Attala, Benton, Calhoun, Carroll, Chickasaw and 32 more115 min
Apr 14, 9:40 AM CDTMesoscale DiscussionSPCGeorge, Greene, Jackson95 min
Apr 14, 10:36 AM CDTTornado WatchSPCGeorge, Greene, Harrison, Jackson, Perry, Stone and 1 more8 hr
Apr 14, 12:41 PM CDTMesoscale DiscussionSPCGeorge, Greene, Jackson94 min
Apr 14, 2:56 PM CDTMesoscale DiscussionSPCJackson94 min
Apr 14, 6:17 PM CDTMesoscale DiscussionSPCGeorge, Jackson118 min
Apr 14, 6:55 PM CDTTornado WatchSPCGeorge, Greene6 hr

Nearby

Tornado Watches in Mississippi, 2018Tornado Watches in Louisiana, 2018Tornado Watches in Arkansas, 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.