Alert archive / Arkansas / Mesoscale Discussions in 2018

Mesoscale Discussion 1678

December 1, 20184 states

The Storm Prediction Center issued this mesoscale discussion at Dec 1, 2018, 3:25 AM CST for 4 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Dec 1, 2018, 3:25 AM CST (09:25 UTC)
Expired
Dec 1, 2018, 5:30 AM CST
In force
2 hr
Issued by
the Storm Prediction Center
All 43 counties

Arkansas County, AR, Ashley County, AR, Bradley County, AR, Chicot County, AR, Clay County, AR, Cleveland County, AR, Craighead County, AR, Crittenden County, AR, Cross County, AR, Desha County, AR, Drew County, AR, Greene County, AR, Jackson County, AR, Jefferson County, AR, Lee County, AR, Lincoln County, AR, Mississippi County, AR, Monroe County, AR, Phillips County, AR, Poinsett County, AR, Prairie County, AR, St. Francis County, AR, Woodruff County, AR, Dunklin County, MO, Pemiscot County, MO, Bolivar County, MS, Coahoma County, MS, DeSoto County, MS, Leflore County, MS, Panola County, MS, Quitman County, MS, Sunflower County, MS, Tallahatchie County, MS, Tate County, MS, Tunica County, MS, Washington County, MS, Dyer County, TN, Fayette County, TN, Haywood County, TN, Lake County, TN, Lauderdale County, TN, Shelby County, TN, Tipton County, TN

The radar

The Memphis radar (KNQA), 100 km from the middle of the area, began a volume at 09:29 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 nearest sounding before it

Little Rock, AR (KBYH), launched 00:00Z, 9.4 hours before the alert went out and 66 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 00:00Z on 2018-12-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 389 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 00:00Z on 2018-12-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 60 square meters per square second.1939587897Sfc1 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
389 J/kg
Mixed-layer CIN
-65 J/kg
Mixed-layer LCL
782 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
60 m²/s²
0-3 km storm-relative helicity
161 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

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
Nov 30, 6:17 PM CSTMesoscale DiscussionSPCArkansas, Ashley, Bradley, Calhoun, Clark, Cleburne and 47 more58 min
Nov 30, 6:40 PM CSTTornado WatchSPCArkansas, Baxter, Benton, Boone, Bradley, Calhoun and 63 more7 hr
Nov 30, 9:02 PM CSTMesoscale DiscussionSPCArkansas, Ashley, Bradley, Calhoun, Clark, Cleburne and 50 more58 min
Nov 30, 11:20 PM CSTMesoscale DiscussionSPCBaxter, Benton, Boone, Bradley, Calhoun, Carroll and 41 more85 min
Dec 1, 12:58 AM CSTMesoscale DiscussionSPCArkansas, Ashley, Baxter, Boone, Bradley, Calhoun and 58 more2 hr
Dec 1, 1:58 AM CSTTornado WatchSPCArkansas, Bradley, Calhoun, Clark, Cleburne, Cleveland and 33 more5 hr
Dec 1, 4:31 AM CSTMesoscale DiscussionSPCClarke, Covington, Forrest, George, Greene, Harrison and 9 more59 min
Nov 30, 9:12 PM CSTMesoscale DiscussionSPCBarry, Barton, Christian, Dade, Douglas, Greene and 6 more2 hr
Nov 30, 9:47 PM CSTTornado WatchSPCBarry, Barton, Cedar, Christian, Dade, Dallas and 19 more5 hr
Dec 1, 1:48 PM CSTMesoscale DiscussionSPCPike, Saint Louis, City of Saint Louis117 min
Dec 1, 2:16 PM CSTTornado WatchSPCLincoln, Pike7 hr
Dec 1, 5:28 PM CSTMesoscale DiscussionSPCBedford, Cheatham, Davidson, Decatur, Dickson, Giles and 16 more62 min

Nearby

Mesoscale Discussions in Arkansas, 2018Mesoscale Discussions in Mississippi, 2018Mesoscale Discussions in Tennessee, 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.