Alert archive / Missouri / Flash Flood Watches in 2019

Flash Flood Watch 19, NWS St. Louis, MO

September 27, 20196 counties in Missouri; Adams County, Brown County, Pike County, Illinois

NWS St. Louis, MO issued this flash flood watch at Sep 27, 2019, 3:40 PM CDT for 6 counties in Missouri; Adams County, Brown County, Pike County, Illinois. It took effect at Sep 27, 2019, 7:00 PM CDT. It was in force for 10 hr.

The area

The counties it named.

The facts

Issued
Sep 27, 2019, 3:40 PM CDT (20:40 UTC)
In effect from
Sep 27, 2019, 7:00 PM CDT
Expired
Sep 28, 2019, 5:13 AM CDT
In force
10 hr
Issued by
NWS St. Louis, MO
Flood severity
None

Counties Adams County, IL, Brown County, IL, Pike County, IL, Knox County, MO, Lewis County, MO, Marion County, MO, Monroe County, MO, Ralls County, MO, Shelby County, MO

The radar

The St Louis radar (KLSX), 146 km from the middle of the area, began a volume at 20:41 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, 8.7 hours before the alert went out and 218 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, Davenport, at 12:00Z on 2019-09-27Temperature 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°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Davenport, at 12:00Z on 2019-09-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 346 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
1100 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
346 m²/s²
0-3 km storm-relative helicity
321 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

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 Sep 27, 12:58 PM CDT, 2 hours 42 minutes earlier.

Area forecast discussion, Sep 27, 12:58 PM CDT, 2 hours 42 minutes before
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Hazardous weather outlook, Sep 27, 4:22 AM CDT, 11 hours 18 minutes before
Hazardous Weather Outlook
National Weather Service Saint Louis MO
422 AM CDT Fri Sep 27 2019

ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027-
034>036-041-042-047>052-059>065-072>075-084-085-099-280930-
Adams IL-Audrain MO-Bond IL-Boone MO-Brown IL-Calhoun IL-Callaway MO-
Clinton IL-Cole MO-Crawford MO-Fayette IL-Franklin MO-Gasconade MO-
Greene IL-Iron MO-Jefferson MO-Jersey IL-Knox MO-Lewis MO-Lincoln MO-
Macoupin IL-Madison IL-Madison MO-Marion IL-Marion MO-Moniteau MO-
Monroe IL-Monroe MO-Montgomery IL-Montgomery MO-Osage MO-Pike IL-
Pike MO-Ralls MO-Randolph IL-Reynolds MO-Saint Charles MO-
Saint Clair IL-Saint Francois MO-Saint Louis City MO-Saint Louis MO-
Sainte Genevieve MO-Shelby MO-Warren MO-Washington IL-Washington MO-
422 AM CDT Fri Sep 27 2019

This Hazardous Weather Outlook is for portions of eastern and
central Missouri as well as west central and southwest Illinois.

.DAY ONE...Today and tonight.

Scattered thunderstorms are expected this morning, mainly across
northeast Missouri and west central Illinois.

Thunderstorms are likely from late this afternoon through tonight,
especially across northeast Missouri and west central Illinois. Some
of these storms could be strong to severe with damaging wind, large
hail, and localized flash flooding.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

There is a chance of thunderstorms over parts of the area Saturday
and Sunday.

There is another chance of thunderstorms Tuesday night and Wednesday
across much of the area.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed late this afternoon and this evening.

BSH

In the hours before

Special weather statement, Sep 27, 11:30 AM CDT, 4 hours 10 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Sep 27, 8:41 AM CDTSpecial Weather StatementLSXLewis34 min
Sep 27, 11:23 AM CDTRiver Flood WarningLSXPike44 days
Sep 27, 11:30 AM CDTSpecial Weather StatementLSXKnox30 min
Sep 27, 6:12 PM CDTSevere Thunderstorm WarningLSXKnox48 min
Sep 27, 6:52 PM CDTSevere Thunderstorm WarningLSXKnox, Lewis53 min

Nearby

Flash Flood Watches in Missouri, 2019Flash Flood Watches in Illinois, 2019Every 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; radar from the NEXRAD Level II archive.