Alert archive / Texas / Mesoscale Discussions in 2018

Mesoscale Discussion 32

January 21, 201818 counties in Arkansas; 18 counties in Oklahoma; 34 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Jan 21, 2018, 1:13 PM CST for 18 counties in Arkansas; 18 counties in Oklahoma; 34 counties in Texas. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Jan 21, 2018, 1:13 PM CST (19:13 UTC)
Expired
Jan 21, 2018, 3:15 PM CST
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
80%
All 70 counties

Benton County, AR, Crawford County, AR, Franklin County, AR, Hempstead County, AR, Howard County, AR, Johnson County, AR, Little River County, AR, Logan County, AR, Madison County, AR, Miller County, AR, Montgomery County, AR, Pike County, AR, Polk County, AR, Scott County, AR, Sebastian County, AR, Sevier County, AR, Washington County, AR, Yell County, AR, Adair County, OK, Atoka County, OK, Bryan County, OK, Cherokee County, OK, Choctaw County, OK, Delaware County, OK, Haskell County, OK, Latimer County, OK, LeFlore County, OK, Mayes County, OK, McCurtain County, OK, McIntosh County, OK, Muskogee County, OK, Okmulgee County, OK, Pittsburg County, OK, Pushmataha County, OK, Sequoyah County, OK, Wagoner County, OK, Anderson County, TX, Bowie County, TX, Camp County, TX, Cass County, TX, Cherokee County, TX, Delta County, TX, Fannin County, TX, Franklin County, TX, Freestone County, TX, Gregg County, TX, Harrison County, TX, Henderson County, TX, Hopkins County, TX, Houston County, TX, Hunt County, TX, Kaufman County, TX, Lamar County, TX, Leon County, TX, Limestone County, TX, Marion County, TX, Morris County, TX, Nacogdoches County, TX, Navarro County, TX, Panola County, TX, Rains County, TX, Red River County, TX, Robertson County, TX, Rockwall County, TX, Rusk County, TX, Smith County, TX, Titus County, TX, Upshur County, TX, Van Zandt County, TX, Wood County, TX

The radar

The Shreveport radar (KSHV), 188 km from the middle of the area, began a volume at 19:14 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

Shreveport, LA (KBAD), launched 12:00Z, 7.2 hours before the alert went out and 192 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, Shreveport, LA at 12:00Z on 2018-01-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 71 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, Shreveport, LA at 12:00Z on 2018-01-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 124 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
71 J/kg
Mixed-layer CIN
-9 J/kg
Mixed-layer LCL
472 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
124 m²/s²
0-3 km storm-relative helicity
276 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

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
Jan 21, 3:05 PM CSTTornado WatchSPCBenton, Boone, Carroll, Crawford, Franklin, Hempstead and 16 more8 hr

Nearby

Mesoscale Discussions in Texas, 2018Mesoscale Discussions in Arkansas, 2018Mesoscale Discussions in Oklahoma, 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.