Alert archive / Mississippi / Mesoscale Discussions in 2021
Mesoscale Discussion 85
The Storm Prediction Center issued this mesoscale discussion at Feb 15, 2021, 3:09 AM CST for 5 counties in Alabama; 15 parishes in Louisiana; 29 counties in Mississippi. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Feb 15, 2021, 3:09 AM CST (09:09 UTC)
- Expired
- Feb 15, 2021, 9:15 AM CST
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Freezing rain
All 49 counties
Fayette County, AL, Franklin County, AL, Lamar County, AL, Marion County, AL, Pickens County, AL, Ascension Parish, LA, Assumption Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Iberville Parish, LA, Livingston Parish, LA, Saint Helena Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Martin Parish, LA, Saint Tammany Parish, LA, St. Mary Parish, LA, Tangipahoa Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, Amite County, MS, Clarke County, MS, Clay County, MS, Covington County, MS, Forrest County, MS, Jasper County, MS, Jefferson Davis County, MS, Jones County, MS, Kemper County, MS, Lamar County, MS, Lauderdale County, MS, Lawrence County, MS, Leake County, MS, Lincoln County, MS, Lowndes County, MS, Marion County, MS, Monroe County, MS, Neshoba County, MS, Newton County, MS, Noxubee County, MS, Oktibbeha County, MS, Pearl River County, MS, Pike County, MS, Rankin County, MS, Scott County, MS, Simpson County, MS, Smith County, MS, Walthall County, MS, Winston County, MS
The radar
The Jackson/Brandon,MS radar (KDGX), 81 km from the middle of the area, began a volume at 09:09 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, 9.2 hours before the alert went out and 86 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
- 4 J/kg
- Mixed-layer CIN
- 0 J/kg
- Mixed-layer LCL
- 541 m above ground
- 0-6 km bulk shear
- 49 kt
- 0-1 km storm-relative helicity
- 252 m²/s²
- 0-3 km storm-relative helicity
- 302 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
329
ACUS11 KWNS 150909
SWOMCD
SPC MCD 150909
ALZ000-MSZ000-LAZ000-151515-
Mesoscale Discussion 0085
NWS Storm Prediction Center Norman OK
0309 AM CST Mon Feb 15 2021
Areas affected...parts of southern LA...southern into eastern
MS...northwest AL
Concerning...Freezing rain
Valid 150909Z - 151515Z
SUMMARY...Freezing rain rates 0.05-0.20 inch per 3 hours are
possible through 9am CST.
DISCUSSION...Radar mosaic shows a relatively small precipitation
shield moving northeast from southeast LA towards southern MS as of
3am CST. Surface conditions show temperatures ranging from near
freezing in southern LA to the middle 20s over central MS. Baton
Rouge recently observed over a tenth of liquid-equivalent
precipitation in the past hour (09z observation).
Large-scale ascent, associated with the eastward-migrating shortwave
trough over the southern Great Plains, will steadily increase early
this morning across the lower MS Valley. The leading edge of
stronger ascent is already implied in water-vapor imagery with
convection over southwest LA. The 06z NAM model indicated 3-hourly
precipitation totals generally in the 0.05-0.15 inch range but had
locally higher amounts. Forecast soundings from southern LA
northeastward show a sub-freezing layer beneath a layer near 850 mb
around 5-8 C. The profile will support freezing rain as the primary
precipitation type early this morning. Sleet may intermittently mix
with freezing rain, especially in the northwest quarter of the
discussion area where the depth of cold air is more favorable for
sleet.
..Smith.. 02/15/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...BMX...HUN...MOB...MEG...JAN...LIX...LCH...
LAT...LON 29809204 31509073 34508813 34528748 33978731 30618962
29719084 29559154 29809204SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Feb 15, 9:28 AM CST | Mesoscale Discussion | SPC | Colbert, Fayette, Franklin, Greene, Lamar, Lauderdale and 6 more | 6 hr |
| Feb 15, 11:24 AM CST | Mesoscale Discussion | SPC | Coffee, Dale, Geneva, Henry, Houston | 66 min |
| Feb 15, 11:55 AM CST | Tornado Watch | SPC | Coffee, Covington, Dale, Geneva, Henry, Houston | 5 hr |
| Feb 15, 3:08 PM CST | Mesoscale Discussion | SPC | Houston | 2 hr |
| Feb 14, 10:53 PM CST | Mesoscale Discussion | SPC | Acadia, Allen, Avoyelles, Beauregard, Calcasieu, East Baton Rouge and 10 more | 4 hr |
| Feb 15, 1:08 AM CST | Mesoscale Discussion | SPC | Bienville, Bossier, Caddo, Claiborne, De Soto, Lincoln and 3 more | 6 hr |
| Feb 15, 5:57 AM CST | Mesoscale Discussion | SPC | Benton, Bolivar, Coahoma, DeSoto, Lafayette, Leflore and 8 more | 6 hr |
Nearby
Mesoscale Discussions in Mississippi, 2021Mesoscale Discussions in Louisiana, 2021Mesoscale Discussions in Alabama, 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.