Alert archive / Missouri / Flash Flood Warnings in 2025

Flash Flood Warning 49, NWS St. Louis, MO

August 12, 2025Franklin County, Jefferson County, Missouri

NWS St. Louis, MO issued this flash flood warning at Aug 12, 2025, 6:06 PM CDT for Franklin County, Jefferson County, Missouri. It was in force for 98 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 12, 2025, 6:06 PM CDT (23:06 UTC)
Expired
Aug 12, 2025, 7:44 PM CDT
In force
98 min
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Flood severity
None

Counties Franklin County, MO, Jefferson County, MO

The radar

The St Louis radar (KLSX), 27 km from the middle of the area, began a volume at 23:06 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 12:00Z, 11.1 hours before the alert went out and 261 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, Lincoln, IL at 12:00Z on 2025-08-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 738 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lincoln, IL at 12:00Z on 2025-08-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 85 square meters per square second.1939Sfc1 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
738 J/kg
Mixed-layer CIN
-62 J/kg
Mixed-layer LCL
1235 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
85 m²/s²
0-3 km storm-relative helicity
92 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

Open this sounding in Storm Lab

The text

As transmitted.

569 
WGUS53 KLSX 122306
FFWLSX
MOC071-099-130200-
/O.NEW.KLSX.FF.W.0049.250812T2306Z-250813T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service St Louis MO
606 PM CDT Tue Aug 12 2025

The National Weather Service in St Louis has issued a

* Flash Flood Warning for...
  East Central Franklin County in east central Missouri...
  Northwestern Jefferson County in east central Missouri...

* Until 900 PM CDT.

* At 606 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 2 and 3.5 inches of 
  rain have fallen. Additional rainfall amounts of 0.5 to 1.5 inches 
  are possible in the warned area. Flash flooding is ongoing or 
  expected to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar indicated.

  IMPACT...Flash flooding of small creeks and streams, urban
           areas, highways, streets and underpasses as well as
           other poor drainage and low-lying areas.

* Some locations that will experience flash flooding include...
  Eureka, Pacific, Byrnes Mill, Cedar Hill, High Ridge, Murphy, 
  Cedar Hill Lakes, Dittmer, House Springs, Scotsdale, Parkdale, 
  Catawissa and Robertsville.

This includes the following State Parks...
	Robertsville State Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

&&

LAT...LON 3832 9088 3847 9081 3849 9074 3847 9074
      3848 9073 3848 9072 3847 9072 3847 9070
      3845 9069 3846 9068 3844 9069 3846 9065
      3848 9066 3849 9065 3849 9063 3847 9062
      3848 9060 3850 9059 3850 9051 3830 9057

FLASH FLOOD...RADAR INDICATED

$$

19
1 follow-up statement
577 
WGUS73 KLSX 130044
FFSLSX

Flash Flood Statement
National Weather Service St Louis MO
744 PM CDT Tue Aug 12 2025

MOC071-099-130054-
/O.CAN.KLSX.FF.W.0049.000000T0000Z-250813T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Franklin MO-Jefferson MO-
744 PM CDT Tue Aug 12 2025

...FLASH FLOOD WARNING FOR EAST CENTRAL FRANKLIN AND NORTHWESTERN 
JEFFERSON COUNTIES HAS BEEN REPLACED WITH A FLOOD ADVISORY...

The heavy rain has ended. Minor flooding may continue in poor 
drainage areas. Please continue to heed remaining road closures.

&&

LAT...LON 3847 9081 3849 9074 3847 9074 3848 9073
      3848 9072 3847 9072 3847 9070 3845 9069
      3846 9068 3844 9069 3846 9065 3848 9066
      3849 9065 3849 9063 3847 9062 3848 9060
      3850 9059 3850 9051 3830 9057 3832 9088

$$

19

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 12, 2:48 PM CDTAreal Flood AdvisoryLSXSaint Charles, Saint Louis, City of Saint Louis55 min
Aug 12, 3:43 PM CDTFlash Flood WarningLSXSaint Charles, Saint Louis, City of Saint Louis105 min
Aug 12, 5:28 PM CDTAreal Flood AdvisoryLSXSaint Charles, Saint Louis, City of Saint Louis62 min
Aug 12, 5:36 PM CDTAreal Flood AdvisoryLSXFranklin, Jefferson25 min
Aug 12, 6:01 PM CDTAreal Flood WarningLSXFranklin, Jefferson5 min

Nearby

Flash Flood Warnings in Missouri, 2025Every flash flood warning in 2025

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.