Alert archive / Missouri / Mesoscale Discussions in 2021
Mesoscale Discussion 1502
The Storm Prediction Center issued this mesoscale discussion at Aug 12, 2021, 3:30 PM CDT for 5 counties in Kansas; 28 counties in Missouri. It was in force for 90 min.
The area
The outline as issued.
The facts
- Issued
- Aug 12, 2021, 3:30 PM CDT (20:30 UTC)
- Expired
- Aug 12, 2021, 5:00 PM CDT
- In force
- 90 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 20%
All 33 counties
Douglas County, KS, Johnson County, KS, Leavenworth County, KS, Miami County, KS, Wyandotte County, KS, Audrain County, MO, Boone County, MO, Caldwell County, MO, Callaway County, MO, Carroll County, MO, Cass County, MO, Chariton County, MO, Clay County, MO, Clinton County, MO, Cole County, MO, Cooper County, MO, Howard County, MO, Jackson County, MO, Johnson County, MO, Lafayette County, MO, Linn County, MO, Livingston County, MO, Macon County, MO, Moniteau County, MO, Monroe County, MO, Montgomery County, MO, Morgan County, MO, Pettis County, MO, Platte County, MO, Randolph County, MO, Ray County, MO, Saline County, MO, Shelby County, MO
The radar
The Pleasant Hill radar (KEAX), 86 km from the middle of the area, began a volume at 20:30 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
Topeka, KS (KTOP), launched 12:00Z, 8.5 hours before the alert went out and 193 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
- 951 J/kg
- Mixed-layer CIN
- -437 J/kg
- Mixed-layer LCL
- 1729 m above ground
- 0-6 km bulk shear
- 3 kt
- 0-1 km storm-relative helicity
- 141 m²/s²
- 0-3 km storm-relative helicity
- 228 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.9
The text
As transmitted.
766
ACUS11 KWNS 122030
SWOMCD
SPC MCD 122030
MOZ000-KSZ000-122200-
Mesoscale Discussion 1502
NWS Storm Prediction Center Norman OK
0330 PM CDT Thu Aug 12 2021
Areas affected...Far northeast Kansas and northern Missouri.
Concerning...Severe potential...Watch unlikely
Valid 122030Z - 122200Z
Probability of Watch Issuance...20 percent
SUMMARY...Isolated large hail and damaging wind gusts are possible
into the evening across northeast Kansas and northern and central
Missouri.
DISCUSSION...Mid-level convection which has been present across
northern Kansas and Missouri for much of the morning and early
afternoon has started to sag south. As it does, it will continue to
interact with a more unstable airmass. Effective shear is very weak
across the region with mostly less than 20 knots of flow sampled
through the troposphere from the KTWX VWP. However, the
thermodynamic environment downstream is quite favorable with MLCAPE
around 3500 J/kg, mid level lapse rates around 7.5 C/km, and DCAPE
around 1300 J/kg per SPC mesoanalysis. Therefore, the weak shear
should limit an organized severe threat, but the favorable
thermodynamic profile could support isolated large hail and severe
wind gusts.
The isolated nature of the threat should limit the need for a watch,
but trends will continue to be monitored.
..Bentley/Thompson.. 08/12/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...LSX...SGF...EAX...TOP...
LAT...LON 39549523 39939355 40069243 39659156 39009136 38589176
38399283 38449485 38939535 39549523SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 12, 5:19 PM CDT | Severe Thunderstorm Watch | SPC | Bates, Benton, Camden, Cass, Cole, Cooper and 27 more | 5 hr |
| Aug 12, 6:06 PM CDT | Mesoscale Discussion | SPC | Franklin, Gasconade, Jefferson, Lincoln, Saint Charles, Saint Louis and 2 more | 84 min |
Nearby
Mesoscale Discussions in Missouri, 2021Mesoscale Discussions in Kansas, 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.