Alert archive / Arkansas / Mesoscale Discussions in 2017

Mesoscale Discussion 221

February 28, 20175 states

The Storm Prediction Center issued this mesoscale discussion at Feb 28, 2017, 5:28 PM CST for 5 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Feb 28, 2017, 5:28 PM CST (23:28 UTC)
Expired
Feb 28, 2017, 7:30 PM CST
In force
2 hr
Issued by
the Storm Prediction Center
All 89 counties

Baxter County, AR, Boone County, AR, Clay County, AR, Cleburne County, AR, Conway County, AR, Craighead County, AR, Crittenden County, AR, Cross County, AR, Faulkner County, AR, Fulton County, AR, Garland County, AR, Greene County, AR, Howard County, AR, Independence County, AR, Izard County, AR, Jackson County, AR, Johnson County, AR, Lawrence County, AR, Logan County, AR, Lonoke County, AR, Marion County, AR, Mississippi County, AR, Montgomery County, AR, Newton County, AR, Perry County, AR, Pike County, AR, Poinsett County, AR, Polk County, AR, Pope County, AR, Prairie County, AR, Pulaski County, AR, Randolph County, AR, Saline County, AR, Scott County, AR, Searcy County, AR, Sharp County, AR, St. Francis County, AR, Stone County, AR, Van Buren County, AR, White County, AR, Woodruff County, AR, Yell County, AR, Alexander County, IL, Jackson County, IL, Johnson County, IL, Massac County, IL, Pope County, IL, Pulaski County, IL, Union County, IL, Williamson County, IL, Ballard County, KY, Carlisle County, KY, Fulton County, KY, Graves County, KY, Hickman County, KY, McCracken County, KY, Bollinger County, MO, Butler County, MO, Cape Girardeau County, MO, Carter County, MO, Douglas County, MO, Dunklin County, MO, Howell County, MO, Iron County, MO, Madison County, MO, Mississippi County, MO, New Madrid County, MO, Oregon County, MO, Ozark County, MO, Pemiscot County, MO, Perry County, MO, Reynolds County, MO, Ripley County, MO, Scott County, MO, Shannon County, MO, Stoddard County, MO, Texas County, MO, Wayne County, MO, Wright County, MO, Crockett County, TN, Dyer County, TN, Gibson County, TN, Haywood County, TN, Lake County, TN, Lauderdale County, TN, Obion County, TN, Shelby County, TN, Tipton County, TN, Weakley County, TN

The radar

The Memphis radar (KNQA), 125 km from the middle of the area, began a volume at 23:34 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

Little Rock, AR (KBYH), launched 12:00Z, 11.5 hours before the alert went out and 151 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, Little Rock, AR at 12:00Z on 2017-02-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 410 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, Little Rock, AR at 12:00Z on 2017-02-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 234 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
410 J/kg
Mixed-layer CIN
-37 J/kg
Mixed-layer LCL
526 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
234 m²/s²
0-3 km storm-relative helicity
160 m²/s²
Significant tornado parameter
0.0
Supercell composite
3.3

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
Feb 28, 2:10 AM CSTMesoscale DiscussionSPCArkansas, Ashley, Bradley, Chicot, Desha, Drew and 2 more3 hr
Feb 28, 1:46 PM CSTMesoscale DiscussionSPCBaxter, Benton, Boone, Carroll, Clay, Cleburne and 37 more2 hr
Feb 28, 3:40 PM CSTTornado WatchSPCArkansas, Baxter, Benton, Boone, Carroll, Clark and 50 more6 hr
Feb 28, 2:03 PM CSTMesoscale DiscussionSPCBureau, DeKalb, DuPage, Ford, Fulton, Grundy and 24 more2 hr
Feb 28, 2:19 PM CSTTornado WatchSPCAlexander, Bond, Calhoun, Clinton, Edwards, Fayette and 27 more7 hr
Feb 28, 2:57 PM CSTTornado WatchSPCAdams, Boone, Brown, Bureau, Carroll, Cass and 63 more7 hr
Feb 28, 5:24 PM CSTMesoscale DiscussionSPCBoone, Bureau, Carroll, Cook, DeKalb, DuPage and 28 more96 min

Nearby

Mesoscale Discussions in Arkansas, 2017Mesoscale Discussions in Missouri, 2017Mesoscale Discussions in Tennessee, 2017Every mesoscale discussion 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.