Alert archive / Missouri / Mesoscale Discussions in 2012

Mesoscale Discussion 1901

September 6, 20124 counties in Illinois; 38 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Sep 6, 2012, 2:03 PM CDT for 4 counties in Illinois; 38 counties in Missouri. It was in force for 57 min.

The area

The outline as issued.

The facts

Issued
Sep 6, 2012, 2:03 PM CDT (19:03 UTC)
Expired
Sep 6, 2012, 3:00 PM CDT
In force
57 min
Issued by
the Storm Prediction Center
All 42 counties

Jackson County, IL, Monroe County, IL, Randolph County, IL, Saint Clair County, IL, Bollinger County, MO, Butler County, MO, Callaway County, MO, Cape Girardeau County, MO, Carter County, MO, City of Saint Louis, MO, Cole County, MO, Crawford County, MO, Dent County, MO, Douglas County, MO, Franklin County, MO, Gasconade County, MO, Howell County, MO, Iron County, MO, Jefferson County, MO, Laclede County, MO, Madison County, MO, Maries County, MO, Miller County, MO, Oregon County, MO, Osage County, MO, Perry County, MO, Phelps County, MO, Pulaski County, MO, Reynolds County, MO, Ripley County, MO, Saint Charles County, MO, Saint Francois County, MO, Saint Louis County, MO, Sainte Genevieve County, MO, Scott County, MO, Shannon County, MO, Stoddard County, MO, Texas County, MO, Warren County, MO, Washington County, MO, Wayne County, MO, Wright County, MO

The radar

The St Louis radar (KLSX), 115 km from the middle of the area, began a volume at 19:03 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

Springfield, MO (KSGF), launched 12:00Z, 7.1 hours before the alert went out and 266 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, Springfield, MO at 12:00Z on 2012-09-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 841 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, Springfield, MO at 12:00Z on 2012-09-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 10 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
841 J/kg
Mixed-layer CIN
-167 J/kg
Mixed-layer LCL
1845 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
10 m²/s²
0-3 km storm-relative helicity
32 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 6, 12:28 PM CDTSevere Thunderstorm WatchSPCAlexander, Clinton, Hardin, Jackson, Johnson, Massac and 9 more9 hr
Sep 6, 3:37 PM CDTMesoscale DiscussionSPCAlexander, Franklin, Hardin, Jackson, Johnson, Massac and 10 more83 min
Sep 6, 6:29 PM CDTMesoscale DiscussionSPCAlexander, Franklin, Gallatin, Hardin, Jackson, Jefferson and 9 more91 min
Sep 6, 10:52 AM CDTMesoscale DiscussionSPCBarry, Barton, Bollinger, Butler, Camden, Carter and 40 more83 min

Nearby

Mesoscale Discussions in Missouri, 2012Mesoscale Discussions in Illinois, 2012Every mesoscale discussion in 2012

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.