Alert archive / Missouri / Tornado Watches in 2017

Tornado Watch 102

March 29, 201721 counties in Missouri

The Storm Prediction Center issued this tornado watch at Mar 29, 2017, 8:22 PM CDT for 21 counties in Missouri. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Mar 29, 2017, 8:22 PM CDT (01:22 UTC)
Expired
Mar 30, 2017, 1:47 AM CDT
In force
5 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 21 counties

Boone County, MO, Butler County, MO, Callaway County, MO, Carter County, MO, Cole County, MO, Crawford County, MO, Franklin County, MO, Gasconade County, MO, Iron County, MO, Jefferson County, MO, Madison County, MO, Moniteau County, MO, Montgomery County, MO, Osage County, MO, Reynolds County, MO, Ripley County, MO, Saint Francois County, MO, Sainte Genevieve County, MO, Warren County, MO, Washington County, MO, Wayne County, MO

The radar

The St Louis radar (KLSX), 136 km from the middle of the area, began a volume at 01:24 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
20%
One or more gusts of 65 knots or more
10%
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
50%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Mar 29, 8:46 PM CDTSevere Thunderstorm WarningLSXCole, Osage59 min
Mar 29, 9:57 PM CDTSevere Thunderstorm WarningLSXCallaway, Cole36 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

Springfield, MO (KSGF), launched 00:00Z, 1.4 hours before the alert went out and 258 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, Springfield, MO at 00:00Z on 2017-03-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 708 joules per kilogram.LCLEL10008507005003002001001 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, Springfield, MO at 00:00Z on 2017-03-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 199 square meters per square second.1939587897117Sfc1 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
708 J/kg
Mixed-layer CIN
-5 J/kg
Mixed-layer LCL
1134 m above ground
0-6 km bulk shear
66 kt
0-1 km storm-relative helicity
199 m²/s²
0-3 km storm-relative helicity
271 m²/s²
Significant tornado parameter
0.9
Supercell composite
4.6

Open this sounding in Storm Lab

The text

As transmitted.

882 
WWUS20 KWNS 300120
SEL2  
SPC WW 300120
MOZ000-300800-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 102
NWS Storm Prediction Center Norman OK
820 PM CDT Wed Mar 29 2017

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Southeastern abnd east-central Missouri

* Effective this Wednesday night and Thursday morning from 820 PM
  until 300 AM CDT.

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

SUMMARY...A narrow corridor of severe-thunderstorm potential -- the
risk for large hail, isolated damaging wind and a couple tornadoes
-- may spread northeastward from the domain of tornado watch 99 into
a warm-frontal zone.  Refer to SPC mesoscale discussion 373 for
initial meteorological details.

The tornado watch area is approximately along and 35 statute miles
east and west of a line from 70 miles south of Farmington MO to 35
miles east of Jefferson City MO. For a complete depiction of the
watch see the associated watch outline update (WOUS64 KWNS WOU2).

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 99...WW 100...WW 101...

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 450. Mean
storm motion vector 24035.

...Edwards

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 29, 7:52 PM CDTMesoscale DiscussionSPCBollinger, Butler, Carter, Crawford, Franklin, Gasconade and 9 more53 min
Mar 29, 9:44 PM CDTMesoscale DiscussionSPCBoone, Callaway, Carter, Cole, Crawford, Dent and 24 more91 min
Mar 30, 11:56 AM CDTMesoscale DiscussionSPCBollinger, Cape Girardeau, Madison, Mississippi, New Madrid, Perry and 5 more64 min
Mar 30, 12:31 PM CDTSevere Thunderstorm WatchSPCCape Girardeau, Mississippi, New Madrid, Perry, Sainte Genevieve, Scott7 hr

Nearby

Tornado Watches in Missouri, 2017Every tornado watch in 2017

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.