River Flood Warning 35, NWS St. Louis, MO

365 
WGUS83 KLSX 201803
FLSLSX

Flood Statement
National Weather Service St Louis MO
103 PM CDT Mon Apr 20 2026

...The Flood Warning is extended for the following rivers in
Missouri...

  Meramec River near Arnold.

River forecasts are based on observed precipitation and forecast
precipitation for the next 24 hours.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Motorists should not attempt to drive around barricades or drive cars
through flooded areas.

This product, along with additional weather and stream information,
is available at https://water.noaa.gov/wfo/lsx

&&

MOC099-189-220615-
/O.EXT.KLSX.FL.W.0035.260421T0224Z-260424T1800Z/
/ARNM7.1.ER.260421T0224Z.260422T0000Z.260423T1200Z.NO/
103 PM CDT Mon Apr 20 2026

...FLOOD WARNING NOW IN EFFECT FROM THIS EVENING TO FRIDAY
AFTERNOON...

* WHAT...Minor flooding is forecast.

* WHERE...Meramec River near Arnold.

* WHEN...From this evening to Friday afternoon.

* IMPACTS...At 25.1 feet, St. Louis County closes the following roads
  at this height:  Butler Hill west of Summerhedge Place, Meramec
  Bottom Road between Hagemann Road and Highway 21, Hawkins Road
  south of Meramec Bottom Road, and Old Telegraph Road at Earl Widman
  County Park.

* ADDITIONAL DETAILS...
  - At 12:30 PM CDT Monday the stage was 23.3 feet.
  - Forecast...The river is expected to rise above flood stage late
    this evening to a crest of 25.3 feet tomorrow evening. It will
    then fall below flood stage Thursday morning.
  - Flood stage is 24.0 feet.



&&


All Times CDT Fld   Observed  Forecasts (7:00 am)
Location      Stg     Stage   Tue   Wed   Thu   Fri   Sat

Meramec River
 Arnold       24.0    23.3    24.8  25.3  24.0  22.8  21.5



&&

LAT...LON 3847 9044 3847 9032 3840 9033 3837 9036
      3841 9036 3842 9037 3843 9036 3845 9036
      3845 9041


$$

Fuchs

415 
WGUS83 KLSX 210203
FLSLSX

Flood Statement
National Weather Service St Louis MO
903 PM CDT Mon Apr 20 2026

...The Flood Warning continues for the following rivers in
Missouri...

  Meramec River near Arnold.

River forecasts are based on observed precipitation and forecast
precipitation for the next 24 hours.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Motorists should not attempt to drive around barricades or drive cars
through flooded areas.

This product, along with additional weather and stream information,
is available at https://water.noaa.gov/wfo/lsx

&&

MOC099-189-221415-
/O.EXT.KLSX.FL.W.0035.260421T0600Z-260424T0000Z/
/ARNM7.1.ER.260421T0600Z.260422T0000Z.260422T1800Z.NO/
903 PM CDT Mon Apr 20 2026

...FLOOD WARNING NOW IN EFFECT FROM LATE TONIGHT TO THURSDAY
EVENING...

* WHAT...Minor flooding is forecast.

* WHERE...Meramec River near Arnold.

* WHEN...From late tonight to Thursday evening.

* IMPACTS...At 24.7 feet, Hawkins Road south of Meramec Bottom Road
  begins flooding.

* ADDITIONAL DETAILS...
  - At 8:30 PM CDT Monday the stage was 23.5 feet.
  - Forecast...The river is expected to rise above flood stage just
    after midnight tonight to a crest of 24.8 feet tomorrow evening.
    It will then fall below flood stage early Wednesday afternoon.
  - Flood stage is 24.0 feet.



&&


All Times CDT Fld   Observed  Forecasts (7:00 am)
Location      Stg     Stage   Wed   Thu   Fri   Sat   Sun

Meramec River
 Arnold       24.0    23.5    24.4  23.0  22.4  21.8  21.4



&&

LAT...LON 3847 9044 3847 9032 3840 9033 3837 9036
      3841 9036 3842 9037 3843 9036 3845 9036
      3845 9041


$$

Pfahler

713 
WGUS83 KLSX 211401
FLSLSX

Flood Statement
National Weather Service St Louis MO
901 AM CDT Tue Apr 21 2026

...The Flood Warning continues for the following rivers in
Missouri...

  Meramec River near Arnold.

River forecasts are based on observed precipitation and forecast
precipitation for the next 24 hours.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Motorists should not attempt to drive around barricades or drive cars
through flooded areas.

This product, along with additional weather and stream information,
is available at https://water.noaa.gov/wfo/lsx

&&

MOC099-189-230215-
/O.EXT.KLSX.FL.W.0035.000000T0000Z-260423T0600Z/
/ARNM7.1.ER.260421T1800Z.260421T1800Z.260422T0000Z.NO/
901 AM CDT Tue Apr 21 2026

...FLOOD WARNING NOW IN EFFECT UNTIL LATE WEDNESDAY NIGHT...

* WHAT...Minor flooding is forecast.

* WHERE...Meramec River near Arnold.

* WHEN...Until late Wednesday night.

* IMPACTS...At 24.0 feet, Corisande Hills Road begins flooding at
  this height.  Meramec Bottom Road between Hagemann Road and Highway
  21 begins flooding.

* ADDITIONAL DETAILS...
  - At 8:30 AM CDT Tuesday the stage was 23.8 feet.
  - Forecast...The river is expected to rise to a crest of 24.0 feet
    this afternoon. It will then fall below flood stage this evening.
  - Flood stage is 24.0 feet.



&&


All Times CDT Fld   Observed  Forecasts (7:00 am)
Location      Stg     Stage   Wed   Thu   Fri   Sat   Sun

Meramec River
 Arnold       24.0    23.8    23.7  22.9  22.0  21.6  21.5



&&

LAT...LON 3847 9044 3847 9032 3840 9033 3837 9036
      3841 9036 3842 9037 3843 9036 3845 9036
      3845 9041


$$

Carney

912 
WGUS83 KLSX 220133
FLSLSX

Flood Statement
National Weather Service St Louis MO
833 PM CDT Tue Apr 21 2026

...The Flood Warning is cancelled for the following rivers in
Missouri...

  Meramec River near Arnold.

River forecasts are based on observed precipitation and forecast
precipitation for the next 24 hours.

MOC099-189-220245-
/O.CAN.KLSX.FL.W.0035.000000T0000Z-260422T0133Z/
/ARNM7.1.ER.000000T0000Z.000000T0000Z.000000T0000Z.NO/
833 PM CDT Tue Apr 21 2026

...FLOOD WARNING IS CANCELLED...

The Flood Warning is cancelled for
  the Meramec River near Arnold.

* ADDITIONAL DETAILS...
  - At 8:00 PM CDT Tuesday the stage was 23.5 feet.
  - Forecast...The river is expected to fall to 20.3 feet Monday
    evening.



&&


All Times CDT Fld   Observed  Forecasts (7:00 am)
Location      Stg     Stage   Thu   Fri   Sat   Sun   Mon

Meramec River
 Arnold       24.0    23.5    22.4  21.9  21.5  21.0  20.5



&&

LAT...LON 3847 9044 3847 9032 3840 9033 3837 9036
      3841 9036 3842 9037 3843 9036 3845 9036
      3845 9041


$$

Britt

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
615 PM CDT Sun Apr 19 2026

.KEY MESSAGES...

- Warmer and mostly dry weather is expected for the first half of this
  week.

- The potential for widespread showers and thunderstorms returns
  to the forecast late this week.

&&

.SHORT TERM...  (Through Late Monday Night)
Issued at 138 PM CDT Sun Apr 19 2026

A weak cold front is pushing through the northern forecast area this
afternoon, allowing a cool airmass to graze northeast Missouri
through south-central Illinois tonight and resulting in similar
temperatures to last night. Seeing as little to no frost developed
this morning, confidence is low in widespread frost building
tonight. However, radiational cooling will be at play, so the
potential for patchy frost to develop on elevated surfaces is higher
than yesterday. The cool airmass will push east on Monday, opening
the region back up to low-level southwesterly flow by the afternoon.
Weak WAA will work in tandem with a second day of clear skies to
lift afternoon highs into the low 60s to low 70s - just a touch
warmer than today.

Jaja

&&

.LONG TERM...  (Tuesday through Next Sunday)
Issued at 138 PM CDT Sun Apr 19 2026

The pressure gradient in the low-levels will tighten over the Mid-
Mississippi Valley on Tuesday as low pressure to our north pushes
into high pressure to our southeast. The stronger flow will advect
much warmer air into the region with widespread mid to upper 70s
forecast for highs Tuesday afternoon. After a similarly warm
Wednesday, temperatures will rocket into the low-80s Thursday
afternoon ahead of our next notable system. Deterministic models
match each other well, all placing a southwest-northeast oriented
cold front in northwestern Missouri at 06z Friday. The set-up looks
similar to what we've been seeing these past couple of weeks: A cold
front in the eastern Plains initiates convection that's weakening by
the time it reaches the eastern half Missouri after sunset. How
quickly it does or doesn't weaken will determine our potential for
stronger thunderstorms. The cold front is forecast to clear the CWA
to the south late Friday before buckling back northward as a warm
front and ushering another chance of rain this weekend.

Jaja

&&

.AVIATION...  (For the 00z TAFs through 00z Monday Evening)
Issued at 614 PM CDT Sun Apr 19 2026

Dry and VFR flight conditions will persist this TAF period with
winds slackening around 00z this evening and veering to
northeasterly tonight as a weak cold front continues passing and a
surface high pressure center traverses the Great Lakes. Winds will
continue to veer to southeasterly and southerly on Monday.

Pfahler

&&

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

WFO LSX

Hazardous Weather Outlook
National Weather Service St Louis MO
119 PM CDT Sun Apr 19 2026

ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027-
034>036-041-042-047>052-059>065-072>075-084-085-099-201830-
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-
119 PM CDT Sun Apr 19 2026

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

.DAY ONE...This afternoon and tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

There is a chance of thunderstorms Thursday through Saturday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

Jaja