Alert archive / Missouri / Flash Flood Watches in 2019

Flash Flood Watch 17, NWS St. Louis, MO

August 21, 201920 counties in Missouri; 14 counties in Illinois

NWS St. Louis, MO issued this flash flood watch at Aug 21, 2019, 3:06 PM CDT for 20 counties in Missouri; 14 counties in Illinois. It took effect at Aug 21, 2019, 7:00 PM CDT. It was in force for 15 hr.

The area

The counties it named.

The facts

Issued: Aug 21, 2019, 3:06 PM CDT (20:06 UTC)
In effect from: Aug 21, 2019, 7:00 PM CDT
Expired: Aug 22, 2019, 10:00 AM CDT
In force: 15 hr
Issued by: NWS St. Louis, MO
Flood severity: None

All 34 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, Cole County, MO, Crawford County, MO, Franklin County, MO, Gasconade County, MO, Jefferson County, MO, Lincoln County, MO, Moniteau County, MO, Montgomery County, MO, Osage County, MO, Pike 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 nearest sounding before it

Springfield, MO (KSGF), launched 12:00Z, 8.1 hours before the alert went out and 340 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: 1626 J/kg
Mixed-layer CIN: -173 J/kg
Mixed-layer LCL: 1382 m above ground
0-6 km bulk shear: 5 kt
0-1 km storm-relative helicity: 93 m²/s²
0-3 km storm-relative helicity: 219 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.0

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 21, 1:00 PM CDT, 2 hours 6 minutes earlier.

Area forecast discussion, Aug 21, 1:00 PM CDT, 2 hours 6 minutes before

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Hazardous weather outlook, Aug 21, 4:37 AM CDT, 10 hours 29 minutes before

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In the hours before

Special weather statement, Aug 21, 10:17 AM CDT, 4 hours 49 minutes before

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Local storm report, Aug 21, 10:26 AM CDT, 4 hours 40 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 21, 8:05 AM CDT	Special Weather Statement	LSX	Lewis	40 min
Aug 21, 8:42 AM CDT	Special Weather Statement	LSX	Boone	48 min
Aug 21, 9:44 AM CDT	River Flood Warning	LSX	Boone, Callaway, Cole, Moniteau	21 days
Aug 21, 3:27 PM CDT	Special Weather Statement	LSX	Madison	48 min
Aug 21, 4:16 PM CDT	Special Weather Statement	LSX	Madison	44 min
Aug 21, 4:58 PM CDT	Special Weather Statement	LSX	Madison	62 min
Aug 21, 5:47 PM CDT	Special Weather Statement	LSX	Iron	43 min
Aug 21, 10:17 AM CDT	Special Weather Statement	LSX	Pike	43 min

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.