Alert archive / Missouri / Flash Flood Warnings in 2018

Flash Flood Warning 5, NWS St. Louis, MO

May 16, 2018Ralls County, Missouri

NWS St. Louis, MO issued this flash flood warning at May 16, 2018, 7:42 AM CDT for Ralls County, Missouri. It was in force for 2 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: May 16, 2018, 7:42 AM CDT (12:42 UTC)
Expired: May 16, 2018, 10:06 AM CDT
In force: 2 hr
Issued by: NWS St. Louis, MO
Area: Storm-based polygon
Flood severity: None

County Ralls County, MO

The radar

The St Louis radar (KLSX), 109 km from the middle of the area, began a volume at 12:44 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

Davenport, (KDVN), launched 12:00Z, 0.7 hours before the alert went out and 265 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1634 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: -35 m²/s²
0-3 km storm-relative helicity: -3 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

826 
WGUS53 KLSX 161242
FFWLSX
MOC173-161645-
/O.NEW.KLSX.FF.W.0005.180516T1242Z-180516T1645Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service St Louis MO
742 AM CDT WED MAY 16 2018

The National Weather Service in St Louis has issued a

* Flash Flood Warning for...
  Southwestern Ralls County in northeastern Missouri...

* Until 1145 AM CDT.

* At 741 AM CDT, Doppler radar indicated thunderstorms producing
  heavy rain across the warned area. Up to two inches of rain have 
  already fallen in the past hour. Flash flooding is expected to 
  begin shortly.

* Some locations that will experience flooding include...
  Vandalia and Perry. 

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, country roads, farmland, and other low lying
spots.

Please report flooding to your local law enforcement agency when you
can do so safely.

&&

LAT...LON 3945 9146 3932 9144 3932 9172 3933 9172
      3946 9171

$$

TES

1 follow-up statement

840 
WGUS73 KLSX 161506
FFSLSX

Flash Flood Statement
National Weather Service St Louis MO
1006 AM CDT WED MAY 16 2018

MOC173-161514-
/O.CAN.KLSX.FF.W.0005.000000T0000Z-180516T1645Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Ralls MO-
1006 AM CDT WED MAY 16 2018

...THE FLASH FLOOD WARNING FOR SOUTHWESTERN RALLS COUNTY IS
CANCELLED...

The heavy rain has ended. Flood waters have receded. Flooding is no
longer expected to pose a threat. Please continue to heed any
remaining road closures.

LAT...LON 3945 9146 3932 9144 3932 9172 3933 9172
      3946 9171

$$

Glass

Nearby

Flash Flood Warnings in Missouri, 2018 Every flash flood warning in 2018

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.