Alert archive / Missouri / Flash Flood Warnings in 2020
Flash Flood Warning 21, NWS St. Louis, MO
NWS St. Louis, MO issued this flash flood warning at Jun 21, 2020, 5:28 AM CDT for Jefferson County, Missouri. It was in force for 4 hr. No storm report in the archive falls inside the area while it was in force.
The area
The outline as issued.
The facts
- Issued
- Jun 21, 2020, 5:28 AM CDT (10:28 UTC)
- Expired
- Jun 21, 2020, 9:28 AM CDT
- In force
- 4 hr
- Issued by
- NWS St. Louis, MO
- Area
- Storm-based polygon
- Flood severity
- None
County Jefferson County, MO
The radar
The St Louis radar (KLSX), 33 km from the middle of the area, began a volume at 10:30 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
Springfield, MO (KSGF), launched 00:00Z, 10.5 hours before the alert went out and 338 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.
- Mixed-layer CAPE
- 422 J/kg
- Mixed-layer CIN
- -33 J/kg
- Mixed-layer LCL
- 1338 m above ground
- 0-6 km bulk shear
- 6 kt
- 0-1 km storm-relative helicity
- 3 m²/s²
- 0-3 km storm-relative helicity
- 33 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
600
WGUS53 KLSX 211028
FFWLSX
MOC099-211530-
/O.NEW.KLSX.FF.W.0021.200621T1028Z-200621T1530Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service St Louis MO
528 AM CDT Sun Jun 21 2020
The National Weather Service in St Louis has issued a
* Flash Flood Warning for...
Northern Jefferson County in east central Missouri...
* Until 1030 AM CDT.
* At 526 AM CDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Radar estimates up to 2.5
inches of rain have fallen between 4 AM and 520 AM CDT. Flash
flooding is ongoing or expected to begin shortly.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar indicated.
IMPACT...Flooding of small creeks and streams, urban areas,
highways, streets and underpasses as well as other
drainage and low lying areas.
* Some locations that will experience flooding include...
Arnold, Byrnes Mill, High Ridge, Murphy, Antonia, Barnhart, House
Springs, Imperial, Scotsdale, Parkdale, Kimmswick and Otto.
Additional rainfall amounts of another inch are possible in the
warned area.
This also includes Mastodon Historic Site.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, urban areas, highways, streets and underpasses as
well as other drainage areas and low lying spots.
In hilly terrain there are hundreds of low water crossings which are
potentially dangerous in heavy rain. Do not attempt to cross flooded
roads. Find an alternate route.
&&
LAT...LON 3841 9035 3838 9034 3834 9037 3839 9069
3846 9068 3845 9068 3845 9066 3849 9065
3847 9062 3850 9059 3850 9041 3849 9040
3848 9042 3845 9041 3845 9034
FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...1-3 INCHES IN 1 HOUR
$$
TES1 follow-up statement
637
WGUS73 KLSX 211428
FFSLSX
Flash Flood Statement
National Weather Service St Louis MO
928 AM CDT Sun Jun 21 2020
MOC099-211437-
/O.CAN.KLSX.FF.W.0021.000000T0000Z-200621T1530Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jefferson MO-
928 AM CDT Sun Jun 21 2020
...THE FLASH FLOOD WARNING FOR NORTHERN JEFFERSON COUNTY IS
CANCELLED...
The heavy rain has ended and flood waters have receded. Flooding is
no longer expected to pose a threat. Please continue to heed any
remaining road closures.
LAT...LON 3841 9035 3838 9034 3834 9037 3839 9069
3846 9068 3845 9068 3845 9066 3849 9065
3847 9062 3850 9059 3850 9041 3849 9040
3848 9042 3845 9041 3845 9034
$$
GlassThe office that day
Everything else NWS St. Louis, MO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 21, 3:26 AM CDT | Areal Flood Advisory | LSX | Saint Charles, Saint Louis, City of Saint Louis | 3 hr |
| Jun 21, 4:40 AM CDT | Flash Flood Warning | LSX | Saint Louis, City of Saint Louis | 5 hr |
| Jun 21, 3:08 PM CDT | Severe Thunderstorm Warning | LSX | Marion | 52 min |
| Jun 21, 3:24 PM CDT | Flash Flood Warning | LSX | Lewis, Marion | 6 hr |
Nearby
Flash Flood Warnings in Missouri, 2020Every flash flood warning in 2020
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.