Alert archive / Mississippi / Mesoscale Discussions in 2017
Mesoscale Discussion 155
The Storm Prediction Center issued this mesoscale discussion at Feb 7, 2017, 5:39 PM CST for Wayne County, Mississippi. It was in force for 96 min.
The area
The outline as issued.
The facts
- Issued
- Feb 7, 2017, 5:39 PM CST (23:39 UTC)
- Expired
- Feb 7, 2017, 7:15 PM CST
- In force
- 96 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 20%
County Wayne County, MS
The radar
The Mobile radar (KMOB), 108 km from the middle of the area, began a volume at 23:42 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
Jackson, MS (KJAN), launched 12:00Z, 11.7 hours before the alert went out and 165 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.
- Mixed-layer CAPE
- 442 J/kg
- Mixed-layer CIN
- -42 J/kg
- Mixed-layer LCL
- 583 m above ground
- 0-6 km bulk shear
- 33 kt
- 0-1 km storm-relative helicity
- 241 m²/s²
- 0-3 km storm-relative helicity
- 231 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 2.4
The text
As transmitted.
612
ACUS11 KWNS 072340
SWOMCD
SPC MCD 072339
ALZ000-MSZ000-080115-
Mesoscale Discussion 0155
NWS Storm Prediction Center Norman OK
0539 PM CST Tue Feb 07 2017
Areas affected...A small part of southeast MS and southwest AL
Concerning...Severe potential...Watch unlikely
Valid 072339Z - 080115Z
Probability of Watch Issuance...20 percent
SUMMARY...A localized severe risk may spread southeastward across
parts of the area during the next couple of hours. The anticipated
eventual decrease in severe risk and limited spatial extent of this
potential are presently expected to preclude Watch issuance.
DISCUSSION...A couple of ongoing supercell storms (with recent
tornado and severe hail reports) in east-central MS are expected to
continue spreading southeastward into the early evening hours.
Large-scale subsidence, combined with eventual nocturnal
stabilization of the boundary layer, should tend to restrict the
temporal duration of the severe risk. Nevertheless, well-established
dynamic perturbation pressure gradient forces attendant to the
ongoing rotating updrafts may allow sustenance of this activity for
a couple more hours. Sufficient buoyancy/shear will exist for all
severe hazards in the short term on an isolated/relatively brief
basis.
..Cohen/Hart.. 02/07/2017
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MOB...JAN...
LAT...LON 31528882 31808894 31898844 31818809 31448817 31308850
31528882SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Feb 6, 10:59 PM CST | Severe Thunderstorm Watch | SPC | Coahoma, DeSoto, Panola, Quitman, Tallahatchie, Tate and 1 more | 9 hr |
| Feb 7, 5:59 AM CST | Mesoscale Discussion | SPC | Adams, Amite, Claiborne, Clarke, Copiah, Covington and 28 more | 2 hr |
| Feb 7, 7:28 AM CST | Mesoscale Discussion | SPC | Alcorn, Benton, DeSoto, Marshall, Tate, Tippah and 1 more | 2 hr |
| Feb 7, 7:54 AM CST | Tornado Watch | SPC | Adams, Amite, Claiborne, Clarke, Copiah, Covington and 34 more | 11 hr |
| Feb 7, 10:18 AM CST | Mesoscale Discussion | SPC | Adams, Amite, Claiborne, Copiah, Covington, Forrest and 26 more | 117 min |
| Feb 7, 12:22 PM CST | Mesoscale Discussion | SPC | Attala, Calhoun, Carroll, Chickasaw, Choctaw, Clay and 12 more | 2 hr |
| Feb 7, 12:56 PM CST | Mesoscale Discussion | SPC | Clarke, Covington, Forrest, George, Greene, Hancock and 18 more | 64 min |
Nearby
Mesoscale Discussions in Mississippi, 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.