Alert archive / Kansas / Mesoscale Discussions in 2017

Mesoscale Discussion 792

May 19, 20174 counties in Kansas

The Storm Prediction Center issued this mesoscale discussion at May 19, 2017, 8:57 PM CDT for 4 counties in Kansas. It was in force for 63 min.

The area

The outline as issued.

The facts

Issued
May 19, 2017, 8:57 PM CDT (01:57 UTC)
Expired
May 19, 2017, 10:00 PM CDT
In force
63 min
Issued by
the Storm Prediction Center
Chance of a watch
20%

Counties Douglas County, KS, Franklin County, KS, Osage County, KS, Shawnee County, KS

The radar

The Topeka radar (KTWX), 52 km from the middle of the area, began a volume at 01:58 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 (KFOE), launched 00:00Z, 2.0 hours before the alert went out and 22 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 00:00Z on 2017-05-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 229 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 00:00Z on 2017-05-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 208 square meters per square second.19395878Sfc1 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
229 J/kg
Mixed-layer CIN
-25 J/kg
Mixed-layer LCL
505 m above ground
0-6 km bulk shear
65 kt
0-1 km storm-relative helicity
208 m²/s²
0-3 km storm-relative helicity
482 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.2

Open this sounding in Storm Lab

The text

As transmitted.

415 
ACUS11 KWNS 200158
SWOMCD
SPC MCD 200157 
KSZ000-200300-

Mesoscale Discussion 0792
NWS Storm Prediction Center Norman OK
0857 PM CDT Fri May 19 2017

Areas affected...Northeast KS

Concerning...Severe potential...Watch unlikely 

Valid 200157Z - 200300Z

Probability of Watch Issuance...20 percent

SUMMARY...Localized tornado threat may exist for the next hour or
so.

DISCUSSION...Recent radar imagery shows that a long-lived supercell
has become better organized as it enters an area of residual
low-level moisture near EMP. This slightly more favorable low-level
moisture and the resulting more moist inflow to the storm appears to
have supported an increase in intensity. Recent TWX VAD shows strong
veering within lowest 1 km with 0-1 km SRH over 400 m2/s2, which is
more than enough to support low-level rotation. Some localized
vorticity enhancement is also possible given the storms presence
within the warm frontal zone across the region. Given the limited
spatial extent of the better low-level moisture and continue
nocturnal stabilization, the longevity of the tornado threat with
this supercell is expected to be short-lived. Even so, a localized
tornado threat may exist for the next hour or so for this small
portion of east-central KS.

..Mosier/Hart.. 05/20/2017

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

ATTN...WFO...TOP...

LAT...LON   39039609 39209573 39159541 39009528 38709519 38519527
            38429550 38419603 38569623 39039609

Nearby

Mesoscale Discussions in Kansas, 2017Every mesoscale discussion in 2017

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.