Alert archive / Indiana / Mesoscale Discussions in 2017

Mesoscale Discussion 449

April 5, 20174 states

The Storm Prediction Center issued this mesoscale discussion at Apr 5, 2017, 4:47 PM CDT for 4 states. It was in force for 88 min.

The area

The outline as issued.

The facts

Issued: Apr 5, 2017, 4:47 PM CDT (21:47 UTC)
Expired: Apr 5, 2017, 6:15 PM CDT
In force: 88 min
Issued by: the Storm Prediction Center

All 53 counties

Edwards County, IL, Lawrence County, IL, Wabash County, IL, White County, IL, Bartholomew County, IN, Brown County, IN, Clay County, IN, Daviess County, IN, Dearborn County, IN, Decatur County, IN, Fayette County, IN, Franklin County, IN, Gibson County, IN, Greene County, IN, Hancock County, IN, Hendricks County, IN, Henry County, IN, Jackson County, IN, Jennings County, IN, Johnson County, IN, Knox County, IN, Lawrence County, IN, Marion County, IN, Martin County, IN, Monroe County, IN, Morgan County, IN, Owen County, IN, Putnam County, IN, Ripley County, IN, Rush County, IN, Shelby County, IN, Sullivan County, IN, Union County, IN, Wayne County, IN, Campbell County, KY, Kenton County, KY, Adams County, OH, Brown County, OH, Butler County, OH, Champaign County, OH, Clark County, OH, Clermont County, OH, Clinton County, OH, Darke County, OH, Fayette County, OH, Greene County, OH, Hamilton County, OH, Highland County, OH, Miami County, OH, Montgomery County, OH, Pike County, OH, Preble County, OH, Warren County, OH

The radar

The Indianapolis radar (KIND), 94 km from the middle of the area, began a volume at 21:49 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

Cncnati-Daytn, OH (KILN), launched 12:00Z, 9.8 hours before the alert went out and 181 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1143 m above ground
0-6 km bulk shear: 66 kt
0-1 km storm-relative helicity: 135 m²/s²
0-3 km storm-relative helicity: 229 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

886 
ACUS11 KWNS 052148
SWOMCD
SPC MCD 052147 
OHZ000-KYZ000-INZ000-ILZ000-052315-

Mesoscale Discussion 0449
NWS Storm Prediction Center Norman OK
0447 PM CDT Wed Apr 05 2017

Areas affected...Portions of central/southwest OH...central/southern
IN...southeast IL

Concerning...Severe Thunderstorm Watch 128...

Valid 052147Z - 052315Z

The severe weather threat for Severe Thunderstorm Watch 128
continues.

SUMMARY...The risk for severe storms continues across Severe
Thunderstorm Watch 128.

DISCUSSION...Scattered convective cells continue developing from
parts of southeast IL through southern IN and southwest OH. This
activity lies near and south of a warm front, where dewpoints in the
lower 50s are supporting MLCAPE around 250-500 J/kg (largely driven
by cold temperatures aloft given the lack of low-level moisture). As
forcing for ascent near and ahead of the low -- reflected by 2-hour
pressure falls around 3-4 mb -- continues overlapping with
sufficient buoyancy, storms should develop northeastward and
eastward through the evening. Large hail and locally damaging wind
gusts will remain possible with the most intense storms. A tornado
could also occur near the warm front in conjunction with effective
SRH around 200-300 m2/s2 -- especially ahead of the surface low in
the presence of pre-existing vertical vorticity. However, the lack
of more appreciable moisture, and related minimal low-level
buoyancy, will tend to restrict the tornado risk.

..Cohen.. 04/05/2017

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

ATTN...WFO...ILN...IND...PAH...ILX...

LAT...LON   38098832 38578819 39678698 40068571 40268383 39738324
            38948298 38638339 38748397 39038495 38878634 38488720
            38038791 38098832

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 5, 1:59 PM CDT	Mesoscale Discussion	SPC	Wabash	3 hr
Apr 5, 3:08 PM CDT	Severe Thunderstorm Watch	SPC	Clark, Clay, Crawford, Edwards, Gallatin, Hamilton and 7 more	5 hr
Apr 5, 1:50 PM CDT	Tornado Watch	SPC	Clark, Crawford, Dubois, Floyd, Harrison, Jefferson and 4 more	8 hr
Apr 5, 1:02 PM CDT	Mesoscale Discussion	SPC	Adair, Allen, Anderson, Barren, Boyle, Butler and 33 more	2 hr
Apr 5, 3:51 PM CDT	Mesoscale Discussion	SPC	Adair, Allen, Anderson, Barren, Boyle, Breckinridge and 35 more	84 min
Apr 5, 6:19 PM CDT	Mesoscale Discussion	SPC	Boyd, Carter, Elliott, Floyd, Greenup, Johnson and 8 more	2 hr
Apr 5, 6:57 PM CDT	Mesoscale Discussion	SPC	Adair, Anderson, Bath, Bell, Bourbon, Boyle and 54 more	48 min

Nearby

Mesoscale Discussions in Indiana, 2017 Mesoscale Discussions in Ohio, 2017 Mesoscale Discussions in Illinois, 2017 Every 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.