Alert archive / Kansas / Mesoscale Discussions in 2018

Mesoscale Discussion 1237

August 5, 201811 counties in Kansas

The Storm Prediction Center issued this mesoscale discussion at Aug 5, 2018, 5:38 PM CDT for 11 counties in Kansas. It was in force for 97 min.

The area

The outline as issued.

The facts

Issued
Aug 5, 2018, 5:38 PM CDT (22:38 UTC)
Expired
Aug 5, 2018, 7:15 PM CDT
In force
97 min
Issued by
the Storm Prediction Center
Chance of a watch
20%

Counties Ellis County, KS, Gove County, KS, Graham County, KS, Lane County, KS, Ness County, KS, Norton County, KS, Phillips County, KS, Rooks County, KS, Scott County, KS, Sheridan County, KS, Trego County, KS

The radar

The Goodland radar (KGLD), 141 km from the middle of the area, began a volume at 22:37 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

Dodge City, (KDDC), launched 12:00Z, 10.6 hours before the alert went out and 144 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, Dodge City, at 12:00Z on 2018-08-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Dodge City, at 12:00Z on 2018-08-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 239 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2446 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
239 m²/s²
0-3 km storm-relative helicity
231 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

874 
ACUS11 KWNS 052239
SWOMCD
SPC MCD 052238 
KSZ000-NEZ000-060015-

Mesoscale Discussion 1237
NWS Storm Prediction Center Norman OK
0538 PM CDT Sun Aug 05 2018

Areas affected...North-central KS

Concerning...Severe potential...Watch unlikely 

Valid 052238Z - 060015Z

Probability of Watch Issuance...20 percent

SUMMARY...Hail and strong wind gusts will be possible across
northwest into north-central KS during the next hour or two.

DISCUSSION...Persistent moisture convergence along with modest
synoptic forcing for ascent tied to the enhanced mid/upper flow
farther north has lead to convective initiation over northwest KS
during the past hour. This area is on the southern end of the better
vertical shear and within a pocket of relatively higher instability.
The downstream airmass appears less favorable for sustained
thunderstorm activity, largely as a result of robust daytime heating
and resultant boundary-layer mixing. These factors, coupled with
slightly warmer mid-level temperatures, have resulted in reduced
instability across central KS. Additionally, the displacement
farther south and east of the strong synoptic forcing has resulted
in the presence of more mid-level dry air than areas farther west.
Entrainment of this drier air into the current updrafts and the
reduced instability over the region suggest gradual storm
dissipation should occur. That being said, strong convergence along
the storm outflow may result in storm persistence longer than the
environment would suggest, particularly if the storm becomes
well-organized in the next half hour or so. New development farther
north near the central NE/KS border is also possible. These storms,
if they develop, may also pose an isolated severe risk.

Current expectation is that the small spatial extent of the severe
threat will preclude the need for a watch but convective trends
across the region will be monitored closely.

..Mosier/Hart.. 08/05/2018

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

ATTN...WFO...GID...DDC...GLD...

LAT...LON   39640026 40039990 39969905 38959911 38389961 38200033
            38320081 38460101 38980077 39640026

Nearby

Mesoscale Discussions in Kansas, 2018Every mesoscale discussion in 2018

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.