River Flood Warning 96, NWS St. Louis, MO

928 
WGUS83 KLSX 170310
FLSLSX

Flood Statement
National Weather Service St Louis MO
1010 PM CDT Tue Jun 16 2026

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

  Missouri River at St. Charles.

  Mississippi River at Chester.

  Mississippi River at Clarksville.

  Mississippi River at Mel Price LD.

  Meramec River near Arnold.

  Illinois River at Hardin.

  Mississippi River at Louisiana.

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

  Missouri River at Hermann.

  Missouri River near Chamois.

  Illinois River at Valley City.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

MOC183-189-181515-
/O.EXT.KLSX.FL.W.0096.000000T0000Z-260618T1800Z/
/SCLM7.1.ER.260616T1747Z.260617T0300Z.260617T1200Z.NO/
1010 PM CDT Tue Jun 16 2026

...FLOOD WARNING NOW IN EFFECT UNTIL THURSDAY AFTERNOON...

* WHAT...Minor flooding is occurring and minor flooding is forecast.

* WHERE...Missouri River at St. Charles.

* WHEN...Until Thursday afternoon.

* IMPACTS...At 25.0 feet, Downstream near this stage, Missouri Route
  H at Island Road and agricultural bottomland may begin flooding,
  depending on Mississippi River flow and backwater.

* ADDITIONAL DETAILS...
  - At 10:00 PM CDT Tuesday the stage was 25.2 feet.
  - Recent Activity...The maximum river stage in the 24 hours ending
    at 10:00 PM CDT Tuesday was 25.2 feet.
  - Forecast...The river is expected to fall below flood stage
    tomorrow morning and continue falling to 17.9 feet Sunday
    evening.
  - Flood stage is 25.0 feet.



&&


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

Missouri River
 St. Charles  25.0    25.2    24.0  21.8  19.6  18.2  MSG



&&

LAT...LON 3892 9036 3884 9013 3878 9016 3883 9031
      3869 9045 3860 9069 3867 9076


$$

ILC077-157-MOC157-186-181515-
/O.EXT.KLSX.FL.W.0088.000000T0000Z-260621T1108Z/
/CHSI2.1.ER.260615T1516Z.260618T1800Z.260620T0508Z.NO/
1010 PM CDT Tue Jun 16 2026

...FLOOD WARNING NOW IN EFFECT UNTIL SUNDAY MORNING...

* WHAT...Minor flooding is occurring and minor flooding is forecast.

* WHERE...Mississippi River at Chester.

* WHEN...Until Sunday morning.

* IMPACTS...At 28.0 feet, Unleveed islands near Chester and the
  prison farm floods.

* ADDITIONAL DETAILS...
  - At 10:00 PM CDT Tuesday the stage was 28.0 feet.
  - Recent Activity...The maximum river stage in the 24 hours ending
    at 10:00 PM CDT Tuesday was 28.1 feet.
  - Forecast...The river is expected to rise to a crest of 28.8 feet
    early Thursday afternoon. It will then fall below flood stage
    early Saturday morning.
  - Flood stage is 27.0 feet.



&&


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

Mississippi River
 Chester         27.0    28.0    28.7  28.6  26.3  23.5  21.8



&&

LAT...LON 3799 8992 3790 8977 3786 8973 3776 8945
      3769 8941 3769 8959 3786 8995 3795 9005


$$

MOC073-139-181515-
/O.EXT.KLSX.FL.W.0086.000000T0000Z-260619T0900Z/
/HRNM7.1.ER.260615T0630Z.260617T0000Z.260618T0300Z.NO/
1010 PM CDT Tue Jun 16 2026

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

* WHAT...Minor flooding is occurring and minor flooding is forecast.

* WHERE...Missouri River at Hermann.

* WHEN...Until late Thursday night.

* IMPACTS...At 22.3 feet, Southern portions of Old Rock Road and
  Twisters Road south of Rhineland begin flooding near this height.

* ADDITIONAL DETAILS...
  - At 9:30 PM CDT Tuesday the stage was 22.3 feet.
  - Recent Activity...The maximum river stage in the 24 hours ending
    at 9:30 PM CDT Tuesday was 22.4 feet.
  - Forecast...The river is expected to fall below flood stage late
    tomorrow evening and continue falling to 12.4 feet Tuesday, June
    23.
  - Flood stage is 21.0 feet.



&&


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

Missouri River
 Hermann      21.0    22.3    20.0  16.6  14.4  13.4  12.9



&&

LAT...LON 3873 9160 3875 9136 3866 9119 3859 9119
      3867 9144 3865 9160


$$

ILC013-MOC163-181515-
/O.EXT.KLSX.FL.W.0084.000000T0000Z-260619T0000Z/
/CLKM7.1.ER.260613T0630Z.260615T1030Z.260617T1800Z.NO/
1010 PM CDT Tue Jun 16 2026

...FLOOD WARNING NOW IN EFFECT UNTIL THURSDAY EVENING...

* WHAT...Minor flooding is occurring and minor flooding is forecast.

* WHERE...Mississippi River at Clarksville.

* WHEN...Until Thursday evening.

* IMPACTS...At 25.5 feet, State Route P east of Elsberry begins
  flooding just east of the levee.

* ADDITIONAL DETAILS...
  - At 10:00 PM CDT Tuesday the stage was 25.5 feet.
  - Recent Activity...The maximum river stage in the 24 hours ending
    at 10:00 PM CDT Tuesday was 25.8 feet.
  - Forecast...The river is expected to fall below flood stage early
    tomorrow afternoon and continue falling to 21.2 feet Tuesday,
    June 23.
  - Flood stage is 25.0 feet.



&&


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

Mississippi River
 Clarksville     25.0    25.5    24.2  23.1  22.4  22.2  21.9



&&

LAT...LON 3939 9097 3946 9088 3940 9081 3932 9075
      3925 9071 3925 9083 3930 9090 3932 9088
      3936 9092 3935 9095


$$

MOC027-151-181515-
/O.EXT.KLSX.FL.W.0082.000000T0000Z-260619T0224Z/
/CMSM7.1.ER.000000T0000Z.260616T1445Z.260617T1424Z.NO/
1010 PM CDT Tue Jun 16 2026

...FLOOD WARNING NOW IN EFFECT UNTIL THURSDAY EVENING...

* WHAT...Minor flooding is occurring and minor flooding is forecast.

* WHERE...Missouri River near Chamois.

* WHEN...Until Thursday evening.

* IMPACTS...At 17.0 feet, Flood Stage:  Lower lying bottom land
  begins to flood.

* ADDITIONAL DETAILS...
  - At 9:45 AM CDT Tuesday the stage was 18.3 feet.
  - Recent Activity...The maximum river stage in the 24 hours ending
    at 9:45 AM CDT Tuesday was 18.3 feet.
  - Forecast...The river is expected to fall below flood stage late
    tomorrow morning and continue falling to 8.3 feet Sunday evening.
  - Flood stage is 17.0 feet.



&&


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

Missouri River
 Chamois      17.0    18.3    14.0  11.5  9.5   8.6   MSG



&&

LAT...LON 3864 9198 3871 9185 3873 9160 3865 9160
      3864 9181 3858 9194


$$

ILC149-171-181515-
/O.EXT.KLSX.FL.W.0093.260620T0000Z-000000T0000Z/
/VALI2.1.ER.260620T0000Z.260623T0000Z.000000T0000Z.NO/
1010 PM CDT Tue Jun 16 2026

...FLOOD WARNING NOW IN EFFECT FROM FRIDAY EVENING UNTIL FURTHER
NOTICE...

* WHAT...Minor flooding is forecast.

* WHERE...Illinois River at Valley City.

* WHEN...From Friday evening until further notice.

* IMPACTS...At 14.0 feet, The road to Norbut Fish and Wildlife area
  is flooded.

* ADDITIONAL DETAILS...
  - At 10:00 PM CDT Tuesday the stage was 13.3 feet.
  - Forecast...The river is expected to rise above flood stage Friday
    evening and continue rising to 14.3 feet Monday evening.
    Additional rises are possible thereafter.
  - Flood stage is 14.0 feet.



&&


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

Illinois River
 Valley City  14.0    13.3    13.6  13.9  14.0  14.1  14.2



&&

LAT...LON 3977 9067 3977 9053 3969 9056 3962 9052
      3952 9051 3952 9059 3964 9062 3965 9066
      3967 9065


$$

ILC119-MOC183-181515-
/O.CON.KLSX.FL.W.0095.000000T0000Z-260619T1800Z/
/ALNI2.1.ER.260617T0341Z.260617T1200Z.260618T1200Z.NO/
1010 PM CDT Tue Jun 16 2026

...FLOOD WARNING REMAINS IN EFFECT UNTIL FRIDAY AFTERNOON...

* WHAT...Minor flooding is forecast.

* WHERE...Mississippi River at Mel Price LD.

* WHEN...Until Friday afternoon.

* IMPACTS...At 20.8 feet, Unprotected farm land begins to flood

* ADDITIONAL DETAILS...
  - At 10:00 PM CDT Tuesday the stage was 21.0 feet.
  - Forecast...The river is expected to rise above flood stage late
    this evening to a crest of 21.2 feet tomorrow morning. It will
    then fall below flood stage Thursday morning.
  - Flood stage is 21.0 feet.



&&


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

Mississippi River
 Mel Price LD    21.0    21.0    21.0  19.6  17.7  16.4  15.7



&&

LAT...LON 3889 9014 3889 9009 3881 9001 3881 9017
      3884 9018


$$

MOC099-189-181515-
/O.CON.KLSX.FL.W.0094.000000T0000Z-260620T1000Z/
/ARNM7.1.ER.260617T0900Z.260618T0000Z.260619T0400Z.NO/
1010 PM CDT Tue Jun 16 2026

...FLOOD WARNING REMAINS IN EFFECT UNTIL LATE FRIDAY NIGHT...

* WHAT...Minor flooding is forecast.

* WHERE...Meramec River near Arnold.

* WHEN...Until late Friday night.

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

* ADDITIONAL DETAILS...
  - At 9:30 PM CDT Tuesday the stage was 23.8 feet.
  - Forecast...The river is expected to rise above flood stage late
    tonight to a crest of 24.4 feet tomorrow evening. It will then
    fall below flood stage late Thursday evening.
  - Flood stage is 24.0 feet.



&&


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

Meramec River
 Arnold       24.0    23.8    24.4  23.5  20.6  17.0  14.9



&&

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


$$

ILC013-061-083-181515-
/O.CON.KLSX.FL.W.0092.000000T0000Z-000000T0000Z/
/HARI2.1.ER.260616T1030Z.260622T0600Z.000000T0000Z.NO/
1010 PM CDT Tue Jun 16 2026

...FLOOD WARNING REMAINS IN EFFECT UNTIL FURTHER NOTICE...

* WHAT...Minor flooding is occurring and minor flooding is forecast.

* WHERE...Illinois River at Hardin.

* WHEN...Until further notice.

* IMPACTS...At 25.0 feet, Flood Stage.  Lowland flooding of
  unprotected agricultural land begins.

* ADDITIONAL DETAILS...
  - At 10:00 PM CDT Tuesday the stage was 25.2 feet.
  - Recent Activity...The maximum river stage in the 24 hours ending
    at 10:00 PM CDT Tuesday was 25.2 feet.
  - Forecast...The river is expected to remain steady above flood
    stage at 25.2 feet.
  - Flood stage is 25.0 feet.



&&


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

Illinois River
 Hardin       25.0    25.2    25.4  25.5  25.5  25.5  25.6



&&

LAT...LON 3952 9064 3952 9052 3942 9054 3935 9051
      3931 9053 3898 9052 3897 9049 3890 9054
      3898 9062 3923 9065


$$

ILC149-MOC163-181515-
/O.CON.KLSX.FL.W.0083.000000T0000Z-260619T0900Z/
/LUSM7.1.ER.260612T1715Z.260615T1000Z.260618T0300Z.NO/
1010 PM CDT Tue Jun 16 2026

...FLOOD WARNING REMAINS IN EFFECT UNTIL LATE THURSDAY NIGHT...

* WHAT...Minor flooding is occurring and minor flooding is forecast.

* WHERE...Mississippi River at Louisiana.

* WHEN...Until late Thursday night.

* IMPACTS...At 15.0 feet, The first quarter mile of Edison Avenue
  beyond the railroad tracks begins flooding near this height.

* ADDITIONAL DETAILS...
  - At 10:00 PM CDT Tuesday the stage was 15.7 feet.
  - Recent Activity...The maximum river stage in the 24 hours ending
    at 10:00 PM CDT Tuesday was 16.1 feet.
  - Forecast...The river is expected to fall below flood stage late
    tomorrow evening and continue falling to 12.2 feet Tuesday, June
    23.
  - Flood stage is 15.0 feet.



&&


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

Mississippi River
 Louisiana       15.0    15.7    14.6  13.6  13.0  12.8  12.6



&&

LAT...LON 3946 9110 3953 9099 3946 9088 3939 9097
      3941 9100 3939 9103


$$

Elmore

900 
WGUS83 KLSX 171719
FLSLSX

Flood Statement
National Weather Service St Louis MO
1219 PM CDT Wed Jun 17 2026

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

  Missouri River at St. Charles.

  Missouri River at Hermann.

  Missouri River near Chamois.

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

&&

MOC183-189-190530-
/O.EXT.KLSX.FL.W.0096.000000T0000Z-260619T0600Z/
/SCLM7.1.ER.260616T1747Z.260617T0800Z.260618T0000Z.NO/
1219 PM CDT Wed Jun 17 2026

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

* WHAT...Minor flooding is occurring and minor flooding is forecast.

* WHERE...Missouri River at St. Charles.

* WHEN...Until late Thursday night.

* IMPACTS...At 25.0 feet, Downstream near this stage, Missouri Route
  H at Island Road and agricultural bottomland may begin flooding,
  depending on Mississippi River flow and backwater.

* ADDITIONAL DETAILS...
  - At 12:00 PM CDT Wednesday the stage was 25.1 feet.
  - Recent Activity...The maximum river stage in the 24 hours ending
    at 12:00 PM CDT Wednesday was 25.2 feet.
  - Forecast...The river is expected to fall below flood stage this
    evening and continue falling to 17.8 feet Monday morning.
  - Flood stage is 25.0 feet.



&&


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

Missouri River
 St. Charles  25.0    25.1    24.4  22.6  20.4  18.8  17.8



&&

LAT...LON 3892 9036 3884 9013 3878 9016 3883 9031
      3869 9045 3860 9069 3867 9076


$$

MOC073-139-190530-
/O.EXT.KLSX.FL.W.0086.000000T0000Z-260619T1300Z/
/HRNM7.1.ER.260615T0630Z.260617T0000Z.260618T0700Z.NO/
1219 PM CDT Wed Jun 17 2026

...FLOOD WARNING NOW IN EFFECT UNTIL FRIDAY MORNING...

* WHAT...Minor flooding is occurring and minor flooding is forecast.

* WHERE...Missouri River at Hermann.

* WHEN...Until Friday morning.

* IMPACTS...At 21.3 feet, The southern end of School House Road south
  of Rhineland begins flooding near this height.

* ADDITIONAL DETAILS...
  - At 11:30 AM CDT Wednesday the stage was 21.7 feet.
  - Recent Activity...The maximum river stage in the 24 hours ending
    at 11:30 AM CDT Wednesday was 22.4 feet.
  - Forecast...The river is expected to fall below flood stage just
    after midnight tonight and continue falling to 12.2 feet
    Wednesday, June 24.
  - Flood stage is 21.0 feet.



&&


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

Missouri River
 Hermann      21.0    21.7    20.5  17.4  15.0  13.8  13.1



&&

LAT...LON 3873 9160 3875 9136 3866 9119 3859 9119
      3867 9144 3865 9160


$$

MOC027-151-190445-
/O.EXT.KLSX.FL.W.0082.000000T0000Z-260619T0440Z/
/CMSM7.1.ER.000000T0000Z.260616T1445Z.260617T1640Z.NO/
1219 PM CDT Wed Jun 17 2026

...FLOOD WARNING NOW IN EFFECT UNTIL THURSDAY EVENING...

* WHAT...Minor flooding is occurring.

* WHERE...Missouri River near Chamois.

* WHEN...Until Thursday evening.

* ADDITIONAL DETAILS...
  - At 7:00 AM CDT Wednesday the stage was 17.4 feet.
  - Recent Activity...The maximum river stage in the 24 hours ending
    at 7:00 AM CDT Wednesday was 17.4 feet.
  - Forecast...The river is expected to fall to 8.3 feet Monday
    morning.
  - Flood stage is 17.0 feet.



&&


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

Missouri River
 Chamois      17.0    17.4    15.0  12.3  10.2  9.0   8.3



&&

LAT...LON 3864 9198 3871 9185 3873 9160 3865 9160
      3864 9181 3858 9194


$$

Fuchs

191 
WGUS83 KLSX 180112
FLSLSX

Flood Statement
National Weather Service St Louis MO
812 PM CDT Wed Jun 17 2026

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

  Missouri River at St. Charles.

  Missouri River near Chamois.

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

MOC183-189-180215-
/O.CAN.KLSX.FL.W.0096.000000T0000Z-260618T0112Z/
/SCLM7.1.ER.260616T1747Z.260617T0800Z.260617T2210Z.NO/
812 PM CDT Wed Jun 17 2026

...FLOOD WARNING IS CANCELLED...

The Flood Warning is cancelled for
  the Missouri River at St. Charles.

* ADDITIONAL DETAILS...
  - At 8:00 PM CDT Wednesday the stage was 24.9 feet.
  - Forecast...The river is expected to fall to 22.7 feet Friday
    morning.



&&


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

Missouri River
 St. Charles  25.0    24.9    24.5  22.7  20.7  19.0  18.3



&&

LAT...LON 3892 9036 3884 9013 3878 9016 3883 9031
      3869 9045 3860 9069 3867 9076


$$

MOC027-151-180215-
/O.CAN.KLSX.FL.W.0082.000000T0000Z-260618T0112Z/
/CMSM7.1.ER.000000T0000Z.260616T1445Z.260617T1620Z.NO/
812 PM CDT Wed Jun 17 2026

...FLOOD WARNING IS CANCELLED...

The Flood Warning is cancelled for
  the Missouri River near Chamois.

* ADDITIONAL DETAILS...
  - At 7:00 PM CDT Wednesday the estimated stage was 16.9 feet.
  - Forecast...The river is expected to fall to near 12.5 feet Friday
    morning.



&&


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

Missouri River
 Chamois      17.0    17.4    15.3  12.5  10.3  9.5   9.3



&&

LAT...LON 3864 9198 3871 9185 3873 9160 3865 9160
      3864 9181 3858 9194


$$

Gosselin

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
610 AM CDT Tue Jun 16 2026

.KEY MESSAGES...

- There is a chance of showers and thunderstorms at times today
  through Thursday.

- Some thunderstorms Wednesday afternoon and evening could be
  severe with damaging winds, large hail, and a few tornadoes,
  followed by a low threat of locally heavy rainfall overnight.

- Warm and windy conditions are also expected on Wednesday with
  occasional gusts of 40 to 45 mph outside of thunderstorms.

&&

.SHORT TERM...  (Through Late Wednesday Morning)
Issued at 319 AM CDT Tue Jun 16 2026

An upper-level shortwave within northwesterly flow will continue to
track southeastward through the Midwest and Great Lakes today. An
associated cold front will press southeastward through the CWA this
morning into afternoon, forcing a band of scattered showers,
possibly a few thunderstorms, mainly along a narrow corridor of
weak, prefrontal low to mid-level moist isentropic ascent. Shower
and thunderstorm development along the front itself during the
afternoon and evening is uncertain due to a combination of
seasonably modest moisture return (dewpoints around 60 F) and weak
frontal convergence, although locally strongest in south-
central/southwestern IL. DCAPE of 750 to 1000 J/kg and inverted V
signatures in forecast soundings suggest a threat of gusty winds
with any stronger thunderstorm, but their expected low-topped nature
(low equilibrium levels), 500 to 750 J/kg of MLCAPE, and potential
updraft dry air entrainment (strong wind shear with very dry mid
levels) all lead to low confidence in any severe thunderstorms. High
temperatures will be in the mid-70s to low-80s F, coolest in
northeastern MO/west-central IL which experience FROPA earlier in
the day.

The aforementioned cold front will stall somewhere near southeastern
MO late this evening before lifting back northeastward as a warm
front later tonight through Wednesday morning in response to surface
cyclogenesis in the Northern Plains, ahead of the next shortwave
trough, and intensification of a strong, 50+ kt southwesterly LLJ.
In response to strong WAA and moisture transport, initiation of
showers and thunderstorms is expected to eventually occur Wednesday
morning. CAMs still vary on exactly when and where this development
will take place but the location of the LLJ's nose points to central
or eastern IA, possibly as far south as northeastern MO/west-central
IL with a conditional threat of large hail from elevated supercells.
Upscale growth into an MCS seems likely through the morning with
Corfidi downshear vectors indicating propagation southeastward,
as far southwest as west-central/south-central IL. However, the
vast majority of CAMs keep this MCS out of the CWA, across central
and northern IL. Therefore, morning thunderstorms are not
anticipated to have a significant impact on subsequent instability
later in the day.

Pfahler

&&

.LONG TERM...  (Wednesday Afternoon through Monday)
Issued at 319 AM CDT Tue Jun 16 2026

The warm front will quickly lift northeast of the CWA by the
afternoon, but a cold front trailing an elongated area of low
pressure in the Upper Mississippi River Valley will reach the CWA
during mid-afternoon. The presence of a capping inversion across the
open warm sector suggests that initiation will be largely confined
to these fronts, with initiation along the cold front expected to
take place in the 2 to 4 pm timeframe. Anomalously strong low and
mid-level flow with 45 to 55 kt of deep-layer wind shear combined
with 1500+ J/kg of MLCAPE will be more more than sufficient for
organized severe thunderstorms including supercells. After
initiation, storm mode becomes much less clear considering that
large-scale forcing will not be particularly strong this far
southwest and deep-layer wind shear-front orientation will be
anywhere from 45 to 60 deg. Therefore, a mixed mode of supercells
and line segments are possible with time. All severe hazards appear
likely including damaging winds, large hail, and a few tornadoes,
although storm mode will modulate which hazard is dominant. A strong
tornado (EF2+) is possible as well, with the most favored location
in the CWA being across west-central IL where the highest SRH is
forecast. However, SRH increases along the entire cold front after
sunset as the LLJ intensifies which may lead to a window of greater
tornado potential (assuming destructive storm interactions do not
dominate) before CINH begins to increase, instability decreases, and
convergence along the front also decreases. Overall, the greatest
severe threat will be along/north of I-44 in MO and I-70 in IL with
the tornado threat maximized in west-central IL.

Overnight, confidence decreases in severe weather, but the threat of
locally heavy rainfall increases as the cold front slows and
increases the potential for thunderstorms to train in some locations
south of I-70 in an environment with PW exceeding the 90th
climatological percentile and deep warm cloud depths.

Outside of thunderstorms, strong gusty southwesterly winds of 40 to
45 mph are expected at times through the late Wednesday morning into
afternoon with BL mixing favoring some momentum transfer of the 50+
kt LLJ to the surface. A Wind Advisory could be needed if confidence
increases in deeper mixing and 45+ mph gusts. Additionally,
Wednesday will be the warmest day of the week with 850-hPa
temperatures reaching the 90th climatological percentile along with
some potential downslope warming off the Ozark Plateau, leading to
high temperatures in the mid-80s to low-90s F.

On Thursday, the cold front is expected to slowly depart the CWA,
but showers and thunderstorms are still expected along the front and
on the cool side of the front mainly south of I-70 through the day
with lingering elevated instability and some component of mid-level
flow overrunning the front. With the cooler post-frontal airmass,
and in Thursday's case cloud cover, seasonably cool temperatures are
forecast Thursday and Friday.

Over the weekend, global model guidance continue to advertise upper-
level quasi-zonal flow becoming established with several shortwave
troughs or perturbations navigating the flow, providing
opportunities for showers and thunderstorms at times late Saturday
into early next week. However, these flow patterns are notorious for
low predictability, which significantly decreases confidence in any
details at this juncture.

Pfahler

&&

.AVIATION...  (For the 12z TAFs through 12z Wednesday Morning)
Issued at 609 AM CDT Tue Jun 16 2026

An area of scattered showers and a few thunderstorms will pass
southeastward through the area this morning into afternoon ahead of
a cold front, reflected by PROB30 groups with some uncertainty if
each terminal will be directly impacted. Otherwise, dry and VFR
flight conditions are expected with southwesterly winds becoming
westerly with a few gusts today, veering to northwesterly behind the
front late this morning at KUIN. The front may stall near the I-70
corridor this evening, leading to light and variable winds at St.
Louis metro terminals, KCOU, and KJEF. Winds will become southerly
and then southwesterly on Wednesday along with occasional gusts of
30 to 37 kt late morning into afternoon.

Pfahler

&&

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

WFO LSX