Alert archive / Indiana / Mesoscale Discussions in 2011

Mesoscale Discussion 477

April 19, 201117 counties in Indiana

The Storm Prediction Center issued this mesoscale discussion at Apr 19, 2011, 7:32 PM EDT for 17 counties in Indiana. It was in force for 28 min.

The area

The outline as issued.

The facts

Issued
Apr 19, 2011, 7:32 PM EDT (23:32 UTC)
Expired
Apr 19, 2011, 8:00 PM EDT
In force
28 min
Issued by
the Storm Prediction Center

Counties Boone County, IN, Brown County, IN, Clay County, IN, Clinton County, IN, Greene County, IN, Hamilton County, IN, Hancock County, IN, Hendricks County, IN, Johnson County, IN, Madison County, IN, Marion County, IN, Monroe County, IN, Montgomery County, IN, Morgan County, IN, Owen County, IN, Parke County, IN, Putnam County, IN

The radar

The Indianapolis radar (KIND), 42 km from the middle of the area, began a volume at 23:33 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 11.5 hours before the alert went out and 178 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, Lincoln, IL at 12:00Z on 2011-04-19Temperature 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°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lincoln, IL at 12:00Z on 2011-04-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 189 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
453 m above ground
0-6 km bulk shear
57 kt
0-1 km storm-relative helicity
189 m²/s²
0-3 km storm-relative helicity
345 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.4

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

868 
ACUS11 KWNS 192333
SWOMCD
SPC MCD 192332
INZ000-200000-

MESOSCALE DISCUSSION 0477
NWS STORM PREDICTION CENTER NORMAN OK
0632 PM CDT TUE APR 19 2011

AREAS AFFECTED...CNTRL IND

CONCERNING...SEVERE POTENTIAL...WATCH NEEDED SOON

VALID 192332Z - 200000Z

ENVIRONMENTAL CONDITIONS HAVE BECOME FAVORABLE FOR SEVERE STORMS AND
A WATCH ISSUANCE WILL BE COORDINATED BETWEEN THE SPC AND THE
AFFECTED LOCAL NATIONAL WEATHER SERVICE OFFICES SHORTLY. AS STRONG
LOW PRESSURE SHIFTS E-NEWD AND CONVECTION UPSTREAM MOVES OVER THE
WARM/UNSTABLE SECTOR OVER CNTRL IND...THE THREAT FOR SVR STORMS AND
TORNADOES WILL OCCUR THIS EVENING. A TORNADO WATCH WILL BE REQUIRED
/REFERENCE MCD 476 FOR DETAILS/.

..COHEN.. 04/19/2011

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...IND...

LAT...LON   39368739 40008733 40368670 40258568 39708566 39038617
            38798662 38758730 39368739

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 19, 9:29 AM EDTMesoscale DiscussionSPCBartholomew, Boone, Brown, Clay, Decatur, Delaware and 20 more61 min
Apr 19, 7:46 PM EDTTornado WatchSPCBartholomew, Boone, Brown, Carroll, Clay, Clinton and 39 more9 hr

Nearby

Mesoscale Discussions in Indiana, 2011Every mesoscale discussion in 2011

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.