Alert archive / Kansas / Mesoscale Discussions in 2021
Mesoscale Discussion 1689
The Storm Prediction Center issued this mesoscale discussion at Sep 2, 2021, 9:24 PM CDT for 9 counties in Kansas. It was in force for 96 min.
The area
The outline as issued.
The facts
- Issued
- Sep 2, 2021, 9:24 PM CDT (02:24 UTC)
- Expired
- Sep 2, 2021, 11:00 PM CDT
- In force
- 96 min
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 487
Counties Chase County, KS, Dickinson County, KS, Geary County, KS, Lyon County, KS, Marion County, KS, Morris County, KS, Osage County, KS, Riley County, KS, Wabaunsee County, KS
The radar
The Topeka radar (KTWX), 58 km from the middle of the area, began a volume at 02:25 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
Topeka, KS (KTOP), launched 00:00Z, 2.4 hours before the alert went out and 96 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
- 155 J/kg
- Mixed-layer CIN
- -177 J/kg
- Mixed-layer LCL
- 1035 m above ground
- 0-6 km bulk shear
- 36 kt
- 0-1 km storm-relative helicity
- 212 m²/s²
- 0-3 km storm-relative helicity
- 268 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 3.8
The text
As transmitted.
093
ACUS11 KWNS 030225
SWOMCD
SPC MCD 030224
KSZ000-030400-
Mesoscale Discussion 1689
NWS Storm Prediction Center Norman OK
0924 PM CDT Thu Sep 02 2021
Areas affected...Portions of eastern Kansas
Concerning...Tornado Watch 487...
Valid 030224Z - 030400Z
The severe weather threat for Tornado Watch 487 continues.
SUMMARY...A damaging gust or two remains possible over the next
couple of hours, particularly with a supercell across Lyon County,
KS.
DISCUSSION...Multiple semi-discrete storms/clusters are persisting
across portions of eastern Kansas amid adequate deep-layer ascent
and buoyancy (1000+ J/kg MLCAPE). While deep-layer (50+ kts) and
low-level shear (300 m2/s2 effective SRH) are present across the
warm sector, convective inhibition is increasing with the onset of
nocturnal cooling (i.e. temperatures dropping below 80F in several
locales). That being said, storms should remain organized (evident
via a sustained supercell structure across Lyon County, KS) for at
least a few more hours. However, increasing static stability within
the boundary-layer will diminish efficient downward momentum
transport, limiting damaging gust potential to the most robust storm
updrafts, with the greatest potential for severe associated with the
Lyon County supercell. Otherwise, an overall decrease in severe
potential is expected overnight as the boundary layer further
stabilizes.
..Squitieri/Guyer.. 09/03/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...TOP...ICT...
LAT...LON 38219754 39079720 39349664 39239604 38879560 38409562
38169595 38049671 38089706 38219754SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 2, 7:00 PM CDT | Mesoscale Discussion | SPC | Ellis, Gove, Graham, Jewell, Lincoln, Mitchell and 8 more | 90 min |
| Sep 2, 7:15 PM CDT | Mesoscale Discussion | SPC | Chase, Clay, Dickinson, Geary, Jackson, Lyon and 12 more | 90 min |
| Sep 3, 3:18 PM CDT | Mesoscale Discussion | SPC | Barber, Clark, Comanche, Ford, Harper, Kingman and 6 more | 2 hr |
Nearby
Mesoscale 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.