Alert archive / Missouri / Flash Flood Watches in 2021

Flash Flood Watch 2, NWS St. Louis, MO

April 27, 20218 counties in Missouri; 6 counties in Illinois

NWS St. Louis, MO issued this flash flood watch at Apr 27, 2021, 2:28 PM CDT for 8 counties in Missouri; 6 counties in Illinois. It took effect at Apr 28, 2021, 1:00 PM CDT. It was in force for 16 hr.

The area

The counties it named.

The facts

Issued
Apr 27, 2021, 2:28 PM CDT (19:28 UTC)
In effect from
Apr 28, 2021, 1:00 PM CDT
Expired
Apr 29, 2021, 5:03 AM CDT
In force
16 hr
Issued by
NWS St. Louis, MO
Flood severity
None

Counties Clinton County, IL, Marion County, IL, Monroe County, IL, Randolph County, IL, Saint Clair County, IL, Washington County, IL, Crawford County, MO, Iron County, MO, Jefferson County, MO, Madison County, MO, Reynolds County, MO, Saint Francois County, MO, Sainte Genevieve County, MO, Washington County, MO

The radar

The St Louis radar (KLSX), 83 km from the middle of the area, began a volume at 19:28 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, 7.5 hours before the alert went out and 272 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 2021-04-27Temperature 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°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lincoln, IL at 12:00Z on 2021-04-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 283 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
1542 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
283 m²/s²
0-3 km storm-relative helicity
389 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

997 
WGUS63 KLSX 271928
FFALSX

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service St Louis MO
228 PM CDT Tue Apr 27 2021

ILZ069-070-074-079-101-102-MOZ065-072>075-084-085-099-281000-
/O.NEW.KLSX.FF.A.0002.210428T1800Z-210429T1500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Clinton IL-Marion IL-Washington IL-Randolph IL-Saint Clair-Monroe
IL-Jefferson MO-Crawford MO-Washington MO-Saint Francois MO-
Sainte Genevieve MO-Iron MO-Madison MO-Reynolds MO-
Including the cities of Cahokia, Centralia, Farmington, Sparta,
Belleville, Salem, and Chester
228 PM CDT Tue Apr 27 2021

...FLASH FLOOD WATCH IN EFFECT FROM WEDNESDAY AFTERNOON THROUGH 
THURSDAY MORNING...

The National Weather Service in St Louis has issued a

* Flash Flood Watch for Portions of Illinois, including the 
  following areas, Clinton IL, Marion IL, Monroe IL, Randolph IL, 
  Saint Clair and Washington IL. Portions of Missouri, including the 
  following areas, Crawford MO, Iron MO, Jefferson MO, Madison MO, 
  Reynolds MO, Saint Francois MO, Sainte Genevieve MO and Washington 
  MO.

* From Wednesday afternoon through Thursday morning.

* Several rounds of heavy rain, especially Wednesday afternoon, may 
  cause flash flooding.

* Excessive runoff may result in flooding of rivers, creeks, 
  streams, and other low-lying and flood-prone locations. Low-water 
  crossings may be flooded.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

Carney
4 follow-up statements
047 
WGUS63 KLSX 280824
FFALSX

Flood Watch
National Weather Service St Louis MO
324 AM CDT Wed Apr 28 2021

ILZ069-070-074-079-101-102-MOZ065-072>075-084-085-099-282130-
/O.CON.KLSX.FF.A.0002.210428T1800Z-210429T1500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Clinton IL-Marion IL-Washington IL-Randolph IL-Saint Clair-Monroe
IL-Jefferson MO-Crawford MO-Washington MO-Saint Francois MO-
Sainte Genevieve MO-Iron MO-Madison MO-Reynolds MO-
Including the cities of Cahokia, Centralia, Farmington, Sparta,
Belleville, Salem, and Chester
324 AM CDT Wed Apr 28 2021

...FLASH FLOOD WATCH REMAINS IN EFFECT FROM 1 PM CDT THIS AFTERNOON 
THROUGH THURSDAY MORNING...

The Flash Flood Watch continues for

* Portions of Illinois, including the following areas, Clinton IL, 
  Marion IL, Monroe IL, Randolph IL, Saint Clair and Washington IL. 
  Portions of Missouri, including the following areas, Crawford MO, 
  Iron MO, Jefferson MO, Madison MO, Reynolds MO, Saint Francois MO, 
  Sainte Genevieve MO and Washington MO.

* From 1 PM CDT this afternoon through Thursday morning.

* Several rounds of heavy rain, especially Wednesday afternoon and 
  night, may cause flash flooding.

* Excessive runoff may result in flooding of rivers, creeks, 
  streams, and other low-lying and flood-prone locations.
  Creeks and streams may rise out of their banks.
  Low-water crossings may be flooded.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

Gosselin
611 
WGUS63 KLSX 282023
FFALSX

Flood Watch
National Weather Service St Louis MO
323 PM CDT Wed Apr 28 2021

ILZ069-070-074-079-101-102-MOZ065-072>075-084-085-099-291000-
/O.CON.KLSX.FF.A.0002.000000T0000Z-210429T1500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Clinton IL-Marion IL-Washington IL-Randolph IL-Saint Clair-Monroe
IL-Jefferson MO-Crawford MO-Washington MO-Saint Francois MO-
Sainte Genevieve MO-Iron MO-Madison MO-Reynolds MO-
Including the cities of Cahokia, Centralia, Farmington, Sparta,
Belleville, Salem, and Chester
323 PM CDT Wed Apr 28 2021

...FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH THURSDAY MORNING...

The Flash Flood Watch continues for

* Portions of Illinois, including the following areas, Clinton IL, 
  Marion IL, Monroe IL, Randolph IL, Saint Clair and Washington IL. 
  Portions of Missouri, including the following areas, Crawford MO, 
  Iron MO, Jefferson MO, Madison MO, Reynolds MO, Saint Francois MO, 
  Sainte Genevieve MO and Washington MO.

* Through Thursday morning.

* Several rounds of heavy rain tonight into Thursday morning may 
  cause flash flooding.

* Excessive runoff may result in flooding of rivers, creeks, 
  streams, and other low-lying and flood-prone locations.
  Creeks and streams may rise out of their banks.
  Low-water crossings may be flooded.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

GKS
162 
WGUS63 KLSX 290852
FFALSX

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service St Louis MO
352 AM CDT Thu Apr 29 2021

ILZ101-102-MOZ065-072-073-291000-
/O.CAN.KLSX.FF.A.0002.000000T0000Z-210429T1500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Saint Clair-Monroe IL-Jefferson MO-Crawford MO-Washington MO-
Including the cities of Belleville and Cahokia
352 AM CDT Thu Apr 29 2021

...FLASH FLOOD WATCH IS CANCELLED...

The Flash Flood Watch for Portions of southwest Illinois, including 
the following areas, Monroe IL and Saint Clair. Portions of east 
central Missouri, including the following areas, Crawford MO, 
Jefferson MO and Washington MO has been cancelled.

The Flood Watch is cancelled with rainfall moving out of the area. 

$$

ILZ069-070-074-079-MOZ074-075-084-085-099-291200-
/O.EXT.KLSX.FF.A.0002.000000T0000Z-210429T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Clinton IL-Marion IL-Washington IL-Randolph IL-Saint Francois MO-
Sainte Genevieve MO-Iron MO-Madison MO-Reynolds MO-
Including the cities of Centralia, Farmington, Salem, Chester,
and Sparta
352 AM CDT Thu Apr 29 2021

...FLASH FLOOD WATCH NOW IN EFFECT UNTIL 7 AM CDT THIS MORNING...

The Flash Flood Watch is now in effect for

* Portions of Illinois, including the following areas, Clinton IL, 
  Marion IL, Randolph IL and Washington IL. Portions of southeast 
  Missouri, including the following areas, Iron MO, Madison MO, 
  Reynolds MO, Saint Francois MO and Sainte Genevieve MO.

* Until 7 AM CDT this morning.

* Heavy Rainfall

* Excessive runoff may result in flooding of rivers, creeks, 
  streams, and other low-lying and flood-prone locations.
  Creeks and streams may rise out of their banks.
  Low-water crossings may be flooded.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

Gosselin
561 
WGUS63 KLSX 291003
FFALSX

Flood Watch
National Weather Service St Louis MO
503 AM CDT Thu Apr 29 2021

ILZ069-070-074-079-MOZ074-075-084-085-099-291115-
/O.CAN.KLSX.FF.A.0002.000000T0000Z-210429T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Clinton IL-Marion IL-Washington IL-Randolph IL-Saint Francois MO-
Sainte Genevieve MO-Iron MO-Madison MO-Reynolds MO-
Including the cities of Centralia, Farmington, Salem, Chester,
and Sparta
503 AM CDT Thu Apr 29 2021

...FLASH FLOOD WATCH IS CANCELLED...

The Flash Flood Watch for Portions of Illinois, including the 
following areas, Clinton IL, Marion IL, Randolph IL and Washington 
IL. Portions of southeast Missouri, including the following areas, 
Iron MO, Madison MO, Reynolds MO, Saint Francois MO and Sainte 
Genevieve MO. has been cancelled.

The Flood Watch is cancelled. Flooding is no longer expected to pose 
a threat. Please continue to heed remaining road closures.

$$

Gosselin

Nearby

Flash Flood Watches in Missouri, 2021Flash Flood Watches in Illinois, 2021Every flash flood watch in 2021

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.