Alert archive / Missouri / Mesoscale Discussions in 2004

Mesoscale Discussion 2327

October 18, 20049 counties in Illinois; 42 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Oct 18, 2004, 3:41 PM CDT for 9 counties in Illinois; 42 counties in Missouri. It was in force for 94 min.

The area

The outline as issued.

The facts

Issued
Oct 18, 2004, 3:41 PM CDT (20:41 UTC)
Expired
Oct 18, 2004, 5:15 PM CDT
In force
94 min
Issued by
the Storm Prediction Center
All 51 counties

Alexander County, IL, Clinton County, IL, Jackson County, IL, Monroe County, IL, Perry County, IL, Randolph County, IL, Saint Clair County, IL, Union County, IL, Washington County, IL, Bollinger County, MO, Butler County, MO, Camden 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, Mississippi County, MO, Moniteau County, MO, New Madrid County, MO, Oregon County, MO, Osage County, MO, Ozark County, MO, Perry County, MO, Phelps County, MO, Pulaski County, MO, Reynolds County, MO, Ripley 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, Webster County, MO, Wright County, MO

The radar

The St Louis radar (KLSX), 109 km from the middle of the area, began a volume at 20:43 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, 8.7 hours before the alert went out and 239 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 2004-10-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2097 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 2004-10-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 333 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
2097 J/kg
Mixed-layer CIN
-105 J/kg
Mixed-layer LCL
619 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
333 m²/s²
0-3 km storm-relative helicity
320 m²/s²
Significant tornado parameter
0.0
Supercell composite
7.0

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
Oct 17, 10:01 PM CDTMesoscale DiscussionSPCMonroe, Randolph3 hr
Oct 17, 11:30 PM CDTSevere Thunderstorm WatchSPCMonroe, Randolph, Saint Clair6 hr
Oct 18, 2:19 AM CDTMesoscale DiscussionSPCAlexander, Monroe, Randolph, Saint Clair56 min
Oct 18, 4:40 AM CDTMesoscale DiscussionSPCAlexander, Bond, Calhoun, Clay, Clinton, Fayette and 16 more35 min
Oct 18, 7:44 AM CDTMesoscale DiscussionSPCAlexander, Massac, Pulaski61 min
Oct 18, 10:20 AM CDTMesoscale DiscussionSPCAlexander, Bond, Clay, Clinton, Edwards, Effingham and 27 more85 min
Oct 18, 12:04 PM CDTMesoscale DiscussionSPCAlexander, Jackson, Monroe, Pulaski, Randolph, Union86 min
Oct 18, 12:40 PM CDTTornado WatchSPCAlexander, Clinton, Jackson, Monroe, Perry, Randolph and 2 more5 hr
Oct 18, 1:55 PM CDTMesoscale DiscussionSPCGallatin, Hardin, Johnson, Massac, Pope, Pulaski and 2 more95 min
Oct 18, 5:05 PM CDTTornado WatchSPCAlexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 17 more5 hr
Oct 18, 6:05 PM CDTMesoscale DiscussionSPCBond, Clay, Clinton, Crawford, Edwards, Effingham and 23 more115 min
Oct 18, 4:05 PM CDTTornado WatchSPCDunklin, Pemiscot5 hr

Nearby

Mesoscale Discussions in Missouri, 2004Mesoscale Discussions in Illinois, 2004Every mesoscale discussion in 2004

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.