Alert archive / Mississippi / Mesoscale Discussions in 2021
Mesoscale Discussion 1676
The Storm Prediction Center issued this mesoscale discussion at Sep 1, 2021, 7:21 PM CDT for 26 counties in Mississippi. It was in force for 84 min.
The area
The outline as issued.
The facts
- Issued
- Sep 1, 2021, 7:21 PM CDT (00:21 UTC)
- Expired
- Sep 1, 2021, 8:45 PM CDT
- In force
- 84 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 5%
All 26 counties
Clarke County, MS, Copiah County, MS, Covington County, MS, Forrest County, MS, Greene County, MS, Hinds County, MS, Jasper County, MS, Jefferson Davis County, MS, Jones County, MS, Lamar County, MS, Lauderdale County, MS, Lawrence County, MS, Leake County, MS, Lincoln County, MS, Madison County, MS, Marion County, MS, Newton County, MS, Perry County, MS, Rankin County, MS, Scott County, MS, Simpson County, MS, Smith County, MS, Walthall County, MS, Warren County, MS, Wayne County, MS, Yazoo County, MS
The radar
The Jackson/Brandon,MS radar (KDGX), 54 km from the middle of the area, began a volume at 00:23 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 00:00Z, 0.4 hours before the alert went out and 63 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
- 1607 J/kg
- Mixed-layer CIN
- -3 J/kg
- Mixed-layer LCL
- 1520 m above ground
- 0-6 km bulk shear
- 20 kt
- 0-1 km storm-relative helicity
- 33 m²/s²
- 0-3 km storm-relative helicity
- 82 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
770
ACUS11 KWNS 020021
SWOMCD
SPC MCD 020021
ALZ000-MSZ000-LAZ000-020145-
Mesoscale Discussion 1676
NWS Storm Prediction Center Norman OK
0721 PM CDT Wed Sep 01 2021
Areas affected...southern Mississippi
Concerning...Severe potential...Watch unlikely
Valid 020021Z - 020145Z
Probability of Watch Issuance...5 percent
SUMMARY...The potential for sporadic wind damage to trees and power
lines will persist for a couple more hours this evening before
diminishing with the loss of diurnal heating.
DISCUSSION...A line of thunderstorms capable of producing strong,
gusty thunderstorm outflows continues to push southward across
Mississippi this evening. Although large-scale deep-layer shear is
weak, storm-scale and mesoscale processes have resulted in shear
around 30 knots across the area. Additionally, extreme instability
has resulted in the development of a robust cold pool that continues
to push southward, with new thunderstorm development along the
leading edge. The overall environment will continue to support the
potential for strong, cold downdrafts capable of producing sporadic
wind damage, especially to trees and power lines, for the next
couple of hours given relatively steep low-level lapse rates. The
threat should diminish later this evening as the boundary layer
stabilizes, and lapse rates weaken, with the loss of diurnal
heating.
..Marsh/Guyer.. 09/02/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MOB...JAN...LIX...
LAT...LON 32329091 32809035 32768931 32488848 31568828 31098842
30908895 31048998 31649082 32329091Nearby
Mesoscale Discussions in Mississippi, 2021Every mesoscale discussion in 2021
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.