Flash Flood Warning 51, NWS St. Louis, MO

573 
WGUS73 KLSX 240018
FFSLSX

Flash Flood Statement
National Weather Service St Louis MO
718 PM CDT Tue Sep 23 2025

ILC005-051-240115-
/O.CON.KLSX.FF.W.0051.000000T0000Z-250924T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bond IL-Fayette IL-
718 PM CDT Tue Sep 23 2025

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 815 PM CDT THIS 
EVENING FOR NORTHEASTERN BOND AND CENTRAL FAYETTE COUNTIES...

At 718 PM CDT, Doppler radar indicated that the thunderstorms 
producing heavy rain across the warned area had ended. While the 
heaviest rain is over, it will take some time for high waters to 
recede.

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...
  Vandalia, Greenville, St. Elmo, Brownstown, Mulberry Grove, 
  Shobonier, Woburn, Avena, Pleasant Mound, Pittsburg, St. Peter, 
  Smithboro, Hagerstown, St. Paul, Loogootee, St. James and 
  Dudleyville.

This includes Interstate 70 in Illinois between exits 45 and 76.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3899 8926 3905 8881 3882 8881 3882 8943
      3896 8944

FLASH FLOOD...RADAR INDICATED

$$

Kimble

Area Forecast Discussion
National Weather Service Saint Louis MO
223 PM CDT Tue Sep 23 2025

.KEY MESSAGES...

- Widespread showers with embedded thunderstorms will continue
tonight into Wednesday providing beneficial rainfall to the
area.

- Dry weather is forecast Thursday afternoon through the weekend
  with temperatures moderating back above normal.

&&

.SHORT TERM...  (Through Late Wednesday Night)
Issued at 222 PM CDT Tue Sep 23 2025

Widespread rain and a few embedded thunderstorms have continued
to march eastward across the area at about a 20-25 mph clip.
Rainfall rates have generally been in the 0.10-0.20" range, though
rainfall rates have been much higher (>1.50"/hr) in areas of
convection. Increasing low-level moisture convergence is expected
this evening, with the strongest convergence expected to be
roughly along/near the I-70 corridor through about 0500 UTC
Wednesday. Overnight, this exits to the east/southeast so the
coverage of rain showers should become more scattered in nature
vs. widespread. This theme of isolated to widely scattered showers
should continue for much of the day on Wednesday. By the
afternoon, a secondary midlevel shortwave trough will moving out
of the south-central Plains. This feature along with some modest
increase in diurnal instability (albeit very weak) should lead to
more widespread showers and possibly a few thunderstorms as well.
This activity should be most prevalent across central and
southeast Missouri Wednesday afternoon before spreading eastward
into southwest Illinois in the evening. The widespread rain then
should advect out of the area late Wednesday night as the midlevel
shortwave departs into the Ohio Valley. In terms of additional
rainfall totals this evening through tomorrow night, most areas
should see at least 0.50" or more of rain, with the exception of
northeast Missouri/west central Illinois. The highest totals
(1.00-1.50") are most likely across eastern Missouri and south-
central Illinois. The 12Z HREF LPMM has some very beefy pockets
(3-5+"), but these totals seem unrealistic due to a member (12Z
HRRR) having a lot of convection, which is not expected. That
being said, I could see some 2-3" totals where any weaker
convection is able to train. If this occurs, this would be most
likely near the aforementioned I-70 corridor in eastern
Missouri/south central Illinois where the low-level moisture
convergence is expected to be strongest this evening.

Temperatures tonight are expected to be on the mild side, with lows
only dropping back into the mid 60s for most locations. Highs on
Wednesday will struggle to rise too much given low clouds, a north
wind, and on/off rain showers. That triumvirate is very good at
holding down temperatures and I think tomorrow will be no exception.
Highs are only expected to be in the low 70s for most locations, or
about 5-7 degrees below normal for the date.

Gosselin

&&

.LONG TERM...  (Thursday through Next Tuesday)
Issued at 222 PM CDT Tue Sep 23 2025

(Thursday)

The closed low across the Great Lakes is forecast to weaken and move
out into the northeastern US by Thursday, with rising mid/upper
level heights across the mid-Mississippi Valley. Rain chances will
decrease through the period, with only some remnant shower activity
possible mainly Wednesday night into Thursday morning.

Daytime highs on Thursday will be a bit on the cool side once again,
though not as cool as Wednesday. Highs in the mid 70s are expected,
just a few degrees below average.

(Thursday Night - Next Tuesday)

Dry weather with warm days and cool nights is forecast beginning
Thursday night along with a dearth of cloud cover for the most part.
Lows are expected to be in the low to mid 50s with highs in the low
to mid 80s.

Gosselin

&&

.AVIATION...  (For the 18z TAFs through 18z Wednesday Afternoon)
Issued at 1207 PM CDT Tue Sep 23 2025

Widespread showers and a few embedded thunderstorms will continue
to march eastward at about 15-20 mph. Visibilities within the rain
showers will predominantly be MVFR, but brief periods of IFR
conditions are expected in the heavier downpours. The rain will
largely stick around through the evening hours before becoming
more scattered as it pushes southeastward. Ceilings will decrease
from west to east this afternoon/evening, with IFR conditions
expected overnight into Wednesday morning. There also will be some
fog around tonight, but ceilings are the main concern as
visibilities likely will stay in the 3-5 SM range. Slowly
improving conditions are expected to begin in terms of
ceilings/visbys Wednesday morning.

Gosselin

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&

WFO LSX

Hazardous Weather Outlook
National Weather Service St Louis MO
230 PM CDT Tue Sep 23 2025

ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027-
034>036-041-042-047>052-059>065-072>075-084-085-099-241930-
Greene IL-Macoupin IL-Montgomery IL-Bond IL-Fayette IL-Clinton IL-
Marion IL-Washington IL-Randolph IL-Adams IL-Brown IL-Pike IL-
Calhoun IL-Jersey IL-Madison IL-Saint Clair IL-Monroe IL-Knox MO-
Lewis MO-Shelby MO-Marion MO-Monroe MO-Ralls MO-Pike MO-Boone MO-
Audrain MO-Moniteau MO-Cole MO-Osage MO-Callaway MO-Montgomery MO-
Lincoln MO-Gasconade MO-Warren MO-Saint Charles MO-Franklin MO-
Saint Louis MO-Saint Louis City MO-Jefferson MO-Crawford MO-
Washington MO-Saint Francois MO-Sainte Genevieve MO-Iron MO-
Madison MO-Reynolds MO-
230 PM CDT Tue Sep 23 2025

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

.DAY ONE...Tonight.

Isolated to scattered thunderstorms are expected through early tonight.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

There is a chance for thunderstorms across much of the area through
Wednesday evening.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

Gosselin