Alert archive / Missouri / Flash Flood Watches in 2019

Flash Flood Watch 15, NWS St. Louis, MO

August 11, 201919 counties in Missouri; 14 counties in Illinois

NWS St. Louis, MO issued this flash flood watch at Aug 11, 2019, 9:17 PM CDT for 19 counties in Missouri; 14 counties in Illinois. It was in force for 13 hr.

The area

The counties it named.

The facts

Issued: Aug 11, 2019, 9:17 PM CDT (02:17 UTC)
Expired: Aug 12, 2019, 10:00 AM CDT
In force: 13 hr
Issued by: NWS St. Louis, MO
Flood severity: None

All 33 counties

Bond County, IL, Calhoun County, IL, Clinton County, IL, Fayette County, IL, Greene County, IL, Jersey County, IL, Macoupin County, IL, Madison County, IL, Marion County, IL, Monroe County, IL, Montgomery County, IL, Randolph County, IL, Saint Clair County, IL, Washington County, IL, Audrain County, MO, Boone County, MO, Callaway County, MO, City of Saint Louis, MO, Franklin County, MO, Gasconade County, MO, Jefferson County, MO, Lincoln County, MO, Monroe County, MO, Montgomery County, MO, Osage County, MO, Pike County, MO, Ralls County, MO, Saint Charles County, MO, Saint Francois County, MO, Saint Louis County, MO, Sainte Genevieve County, MO, Warren County, MO, Washington County, MO

The radar

The St Louis radar (KLSX), 11 km from the middle of the area, began a volume at 02:17 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

Lincoln, IL (KILX), launched 00:00Z, 2.3 hours before the alert went out and 230 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: 1472 J/kg
Mixed-layer CIN: -16 J/kg
Mixed-layer LCL: 786 m above ground
0-6 km bulk shear: 9 kt
0-1 km storm-relative helicity: 42 m²/s²
0-3 km storm-relative helicity: 62 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood watch went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS St. Louis, MO wrote its last area forecast discussion before this flash flood watch went out at Aug 11, 7:03 PM CDT, 2 hours 14 minutes earlier.

Area forecast discussion, Aug 11, 7:03 PM CDT, 2 hours 14 minutes before

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Hazardous weather outlook, Aug 11, 4:54 PM CDT, 4 hours 23 minutes before

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The office that day

Everything else NWS St. Louis, MO issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 12, 3:15 AM CDT	Flash Flood Warning	LSX	Saint Charles, Saint Louis, City of Saint Louis	6 hr
Aug 12, 4:09 AM CDT	Flash Flood Warning	LSX	Audrain, Boone	6 hr
Aug 12, 5:17 AM CDT	Flash Flood Warning	LSX	Callaway, Lincoln, Montgomery, Pike, Warren	5 hr
Aug 12, 9:10 AM CDT	Areal Flood Warning	LSX	Saint Charles, Saint Louis, City of Saint Louis	6 hr
Aug 12, 2:38 AM CDT	Flash Flood Warning	LSX	Bond, Clinton, Fayette, Macoupin, Marion, Montgomery	8 hr
Aug 12, 5:11 AM CDT	Flash Flood Warning	LSX	Clinton, Saint Clair, Washington	5 hr
Aug 12, 10:31 AM CDT	Areal Flood Warning	LSX	Bond, Clinton, Fayette, Macoupin, Marion, Montgomery	3 hr
Aug 12, 10:40 AM CDT	Areal Flood Warning	LSX	Bond, Clinton, Fayette, Macoupin, Marion, Montgomery	17 min
Aug 12, 1:28 PM CDT	Areal Flood Warning	LSX	Bond, Clinton, Fayette, Macoupin, Marion, Montgomery	3 hr
Aug 12, 3:01 PM CDT	Areal Flood Warning	LSX	Madison	9 hr
Aug 12, 4:48 PM CDT	Areal Flood Warning	LSX	Bond, Clinton, Fayette, Macoupin, Marion, Montgomery	9 hr

Nearby

Flash Flood Watches in Missouri, 2019 Flash Flood Watches in Illinois, 2019 Every flash flood watch in 2019

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.