Alert archive / Missouri / Mesoscale Discussions in 2017

Mesoscale Discussion 592

April 29, 2017Monroe County, Randolph County, Saint Clair County, Illinois; 25 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Apr 29, 2017, 12:50 PM CDT for Monroe County, Randolph County, Saint Clair County, Illinois; 25 counties in Missouri. It was in force for 85 min.

The area

The outline as issued.

The facts

Issued
Apr 29, 2017, 12:50 PM CDT (17:50 UTC)
Expired
Apr 29, 2017, 2:15 PM CDT
In force
85 min
Issued by
the Storm Prediction Center
Chance of a watch
40%
All 28 counties

Monroe County, IL, Randolph County, IL, Saint Clair County, IL, Bollinger County, MO, Carter County, MO, City of Saint Louis, MO, Crawford County, MO, Dent County, MO, Franklin County, MO, Gasconade County, MO, Howell County, MO, Iron County, MO, Jefferson County, MO, Madison County, MO, Maries County, MO, Oregon County, MO, Osage County, MO, Perry County, MO, Phelps County, MO, Pulaski County, MO, Reynolds County, MO, Saint Francois County, MO, Saint Louis County, MO, Sainte Genevieve County, MO, Shannon County, MO, Texas County, MO, Washington County, MO, Wayne County, MO

The radar

The St Louis radar (KLSX), 120 km from the middle of the area, began a volume at 17:52 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

Springfield, MO (KSGF), launched 12:00Z, 5.8 hours before the alert went out and 254 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 2017-04-29Temperature 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, Springfield, MO at 12:00Z on 2017-04-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 318 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
704 m above ground
0-6 km bulk shear
72 kt
0-1 km storm-relative helicity
318 m²/s²
0-3 km storm-relative helicity
413 m²/s²
Significant tornado parameter
0.0
Supercell composite
3.6

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 28, 10:01 PM CDTSevere Thunderstorm WatchSPCAlexander, Franklin, Gallatin, Hamilton, Hardin, Jackson and 7 more9 hr
Apr 28, 11:55 PM CDTMesoscale DiscussionSPCAlexander, Franklin, Gallatin, Hardin, Jackson, Johnson and 6 more95 min
Apr 29, 3:39 AM CDTMesoscale DiscussionSPCAlexander, Franklin, Gallatin, Hamilton, Hardin, Jackson and 8 more96 min
Apr 29, 3:28 PM CDTMesoscale DiscussionSPCBond, Clay, Clinton, Crawford, Edwards, Effingham and 20 more2 hr
Apr 29, 3:57 PM CDTSevere Thunderstorm WatchSPCAlexander, Bond, Christian, Clark, Clay, Clinton and 38 more6 hr
Apr 29, 6:30 PM CDTMesoscale DiscussionSPCAlexander, Clark, Clay, Coles, Crawford, Cumberland and 25 more60 min

Nearby

Mesoscale Discussions in Missouri, 2017Mesoscale Discussions in Illinois, 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.