Alert archive / Kansas / Mesoscale Discussions in 2021

Mesoscale Discussion 1660

August 31, 202113 counties in Kansas; 8 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Aug 31, 2021, 7:59 AM CDT for 13 counties in Kansas; 8 counties in Missouri. It was in force for 61 min.

The area

The outline as issued.

The facts

Issued
Aug 31, 2021, 7:59 AM CDT (12:59 UTC)
Expired
Aug 31, 2021, 9:00 AM CDT
In force
61 min
Issued by
the Storm Prediction Center
Concerning
Severe potential...watch unlikely
Chance of a watch
20%
All 21 counties

Atchison County, KS, Brown County, KS, Doniphan County, KS, Douglas County, KS, Jackson County, KS, Jefferson County, KS, Johnson County, KS, Leavenworth County, KS, Marshall County, KS, Nemaha County, KS, Pottawatomie County, KS, Shawnee County, KS, Wyandotte County, KS, Andrew County, MO, Buchanan County, MO, Clay County, MO, Clinton County, MO, DeKalb County, MO, Holt County, MO, Jackson County, MO, Platte County, MO

The radar

The Topeka radar (KTWX), 109 km from the middle of the area, began a volume at 13:01 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 12:00Z, 1.0 hours before the alert went out and 77 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.

Skew-T log-pSkew-T log-p diagram, Topeka, KS at 12:00Z on 2021-08-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 986 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Topeka, KS at 12:00Z on 2021-08-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 88 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
986 J/kg
Mixed-layer CIN
-109 J/kg
Mixed-layer LCL
1015 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
88 m²/s²
0-3 km storm-relative helicity
94 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.9

Open this sounding in Storm Lab

The text

As transmitted.

611 
ACUS11 KWNS 311259
SWOMCD
SPC MCD 311259 
MOZ000-KSZ000-NEZ000-311400-

Mesoscale Discussion 1660
NWS Storm Prediction Center Norman OK
0759 AM CDT Tue Aug 31 2021

Areas affected...Northeast KS and northwest MO

Concerning...Severe potential...Watch unlikely 

Valid 311259Z - 311400Z

Probability of Watch Issuance...20 percent

SUMMARY...Isolated strong-damaging gusts may occur in the next 1-2
hours across northeast KS/northwest MO, but storms are expected to
weaken by mid morning and a watch is not anticipated.

DISCUSSION...A cluster of overnight storms persists this morning,
moving southeastward from southeast NE into northeast KS and
northwest MO.  The storms have been focused atop the outflow from
earlier convection across northern MO, where lift is stronger. 
However, buoyancy is modest and vertical shear weakens with
southward extent (away from the MCV near the MO River), so the
storms are not expected to maintain intensity for very long this
morning.  There will be a threat for isolated strong-damaging gusts
for another hour or two this morning, but the overall expectation is
for the storms to weaken and that a severe thunderstorm watch is not
necessary.

..Thompson.. 08/31/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...EAX...OAX...TOP...

LAT...LON   40359490 40139414 39399401 38929436 38849536 39009615
            39509674 39789658 40039545 40359490

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 31, 3:02 AM CDTMesoscale DiscussionSPCAtchison, Holt, Nodaway, Worth118 min

Nearby

Mesoscale Discussions in Kansas, 2021Mesoscale Discussions in Missouri, 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.