Severe Thunderstorm Warning 77, NWS St. Louis, MO

057 
WWUS53 KLSX 270848
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
348 AM CDT Mon Apr 27 2026

MOC186-187-270915-
/O.CON.KLSX.SV.W.0077.000000T0000Z-260427T0915Z/
Sainte Genevieve MO-Saint Francois MO-
348 AM CDT Mon Apr 27 2026

...SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 415 AM CDT FOR
SAINTE GENEVIEVE AND SOUTHEASTERN SAINT FRANCOIS COUNTIES...

At 348 AM CDT, a severe thunderstorm was located near Coffman, or 8
miles east of Farmington, moving east at 30 mph.

HAZARD...Golf ball size hail and 60 mph wind gusts.

SOURCE...Public reported golf ball sized hail 3 miles southeast of
         Farmington.

IMPACT...People and animals outdoors will be injured. Expect hail
         damage to roofs, siding, windows, and vehicles. Expect wind
         damage to roofs, siding, and trees.

Locations impacted include...
  Libertyville, Rocky Ridge, Weingarten, Bloomsdale, Coffman, Womac,
  River Aux Vases, Ste. Genevieve and Minnith.

This includes the following State Parks...
Hawn State Park and Felix Valle House State Park.

This includes Interstate 55 in Missouri between exits 143 and 162.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Anyone outdoors should move to shelter inside a well-built structure
and stay away from windows. This storm has produced dangerous hail
and is capable of producing damaging winds.

&&

LAT...LON 3769 9034 3798 9032 3806 9037 3809 9021
      3807 9017 3807 9016 3806 9013 3804 9013
      3802 9009 3802 9006 3800 9005 3800 9003
      3799 9002 3777 9003 3767 9011 3765 9014
TIME...MOT...LOC 0836Z 272DEG 26KT 3778 9040

THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...OBSERVED
MAX HAIL SIZE...1.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Delia

842 
WWUS53 KLSX 270906
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
406 AM CDT Mon Apr 27 2026

MOC187-270916-
/O.CAN.KLSX.SV.W.0077.000000T0000Z-260427T0915Z/
Saint Francois MO-
406 AM CDT Mon Apr 27 2026

...SEVERE THUNDERSTORM WARNING IS CANCELLED FOR SOUTHEASTERN SAINT
FRANCOIS COUNTY...

The storm which prompted the warning has moved out of the area.
Therefore, the warning has been cancelled.

&&

LAT...LON 3779 9024 3790 9013 3809 9021 3807 9017
      3806 9013 3804 9013 3802 9009 3801 9006
      3800 9005 3800 9003 3798 9002 3778 9003
      3767 9011 3770 9015 3769 9017
TIME...MOT...LOC 0848Z 272DEG 26KT 3778 9029

$$


MOC186-270915-
/O.CON.KLSX.SV.W.0077.000000T0000Z-260427T0915Z/
Sainte Genevieve MO-
406 AM CDT Mon Apr 27 2026

...SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 415 AM CDT FOR
CENTRAL SAINTE GENEVIEVE COUNTY...

At 406 AM CDT, a severe thunderstorm was located over Coffman, or 15
miles east of Farmington, moving east at 25 mph.

HAZARD...Golf ball size hail and 60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...People and animals outdoors will be injured. Expect hail
         damage to roofs, siding, windows, and vehicles. Expect wind
         damage to roofs, siding, and trees.

Locations impacted include...
  Coffman, River Aux Vases, Minnith and Ste. Genevieve.

This includes the following State Parks...
Felix Valle House State Park.

This includes Interstate 55 in Missouri between exits 143 and 150.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Anyone outdoors should move to shelter inside a well-built structure
and stay away from windows. This storm is capable of producing
dangerous hail and damaging winds.

&&

LAT...LON 3779 9024 3790 9013 3809 9021 3807 9017
      3806 9013 3804 9013 3802 9009 3801 9006
      3800 9005 3800 9003 3798 9002 3778 9003
      3767 9011 3770 9015 3769 9017
TIME...MOT...LOC 0848Z 272DEG 21KT 3778 9029

THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Delia

309 
WWUS53 KLSX 270924
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
424 AM CDT Mon Apr 27 2026

MOC186-270934-
/O.EXP.KLSX.SV.W.0077.000000T0000Z-260427T0915Z/
Sainte Genevieve MO-
424 AM CDT Mon Apr 27 2026

...SEVERE THUNDERSTORM WARNING HAS EXPIRED FOR CENTRAL SAINTE
GENEVIEVE COUNTY...

The storm which prompted the warning has moved out of the area.
Therefore, the warning has been allowed to expire.

&&

LAT...LON 3779 9024 3790 9013 3809 9021 3807 9017
      3806 9013 3804 9013 3802 9009 3801 9006
      3800 9005 3800 9003 3798 9002 3778 9003
      3767 9011 3770 9015 3769 9017
TIME...MOT...LOC 0906Z 272DEG 21KT 3777 9015

$$

Delia

Area Forecast Discussion
National Weather Service Saint Louis MO
157 AM CDT Mon Apr 27 2026

.KEY MESSAGES...

- While periods of storms are expected through Monday morning, the most
  potent thunderstorms will occur this afternoon and evening.

- Thunderstorms this afternoon and evening will be capable of
  damaging wind gusts, large hail, and strong tornadoes.

- A period of cool, calm weather is expected mid-week through the
  weekend.

&&

.SHORT TERM... (Through Tuesday Night)
Issued at 155 AM CDT Mon Apr 27 2026

Storms across southeastern Missouri continue to butt up against an
instability gradient draped from north to south across Missouri.
The warm air advection feeding these storms will also push greater
instability slowly northeastward through this morning, though
propagation vectors will favor convection continuing to move east-
southeastward generally away from the CWA or into an unfavorable
environment. Additionally, the low-level jet refocusing across
Kansas will continue to support the downward trend in convection
across southeastern Missouri early this morning. Any linger storms
over the next couple of hours will be capable mainly of large hail,
though there is also a very low damaging wind and tornado threat for
storms that remain surface based.

Our attention turns to the storms over eastern Kansas that are
propagating eastward with the nose of the low-level jet. With the
nose of this low-level jet edging into northeastern Missouri later
this morning, the focus for these storms will spread into portions
of the CWA north of I-70. Vertical thermal profiles suggest that this
convection will be elevated, mitigating a threat of damaging wind
gusts and/or tornadoes. However, with around 40 kts of effective
shear and building MUCAPE, there is a low chance for isolated
instances of large hail.

How long this convection lingers is uncertain, although guidance
trends have been toward a lull in convective activity in the wake of
this convection and that associated with a cold front during the
late afternoon and evening. Ahead of the front, the warm sector
remains capped through much of the afternoon per a majority of
deterministic soundings. Although, any remnant outflow or
differential heating boundary from early day convection may serve as
enough of a forcing mechanism to spawn discrete convection during
the afternoon as lift from an approaching shortwave increases over
the region. If this convection does form, it will be in an
environment characterized by 2,000-2,500 J/kg of SBCAPE and roughly
50 kts of deep-layer shear. This will favor supercells capable of
all hazards, with long curved hodographs favoring strong tornadoes,
especially if storms are able to latch on to any remnant boundaries
across the CWA.

Where the environment isn't contaminated from earlier rounds of
convection, additional updrafts are expected along the cold front as
it enters the area 4-5pm. Forcing from the front paired with lift
from the shortwave will lead to numerous updrafts along the front.
While this will be occurring within a similar environment detailed
prior, the number of updrafts paired with them occurring along the
front may lead to destructive interactions and congealing into line
segments and/or clusters. While this will tend to limit a strong
tornado threat, storms will still be capable of all severe hazards.
Convection is expected to depart the CWA with the front by 9-10pm.

Even with the FROPA Monday evening, the threat for convection will
continue on Tuesday. Guidance consensus has the front stalling just
south of the CWA early Tuesday and then buckling northward as a
shortwave moves through the Central Plains and into the Midwest
through the day. This shortwave will send a subtle surface
reflection through the Mid South along the front, with a brief
period of warm air advection that will help force elevated
convection for areas mainly along and south of I-70. If the front
can move northward enough, shear profiles and instability amounts
favor supercells capable primarily of large hail across far
southeastern Missouri during the afternoon. Waning instability and
the front continuing southward will bring an end to rain chances
during the evening.

Elmore

&&

.LONG TERM... (Tuesday Night through Sunday)
Issued at 155 AM CDT Mon Apr 27 2026

Both deterministic guidance and ensemble clusters keep upper-level
troughing slowly moving eastward over the eastern CONUS through the
long range forecast period. This will maintain northwesterly flow
over the Middle Mississippi Valley through Saturday as several
rounds of high pressure pass through the region. As a result,
temperatures will run at or below climatological normals into the
weekend and mostly dry weather is expected.

Elmore

&&

.AVIATION...  (For the 06z TAFs through 06z Monday Night)
Issued at 1231 AM CDT Mon Apr 27 2026

Light to moderate rainfall with occasional lightning strikes are
expected at the local terminals through the first several hours of
the TAF period. Thunderstorms currently over Kansas will continue
eastward overnight and through the early morning hours, impacting
KCOU, KJEF, and KUIN during the mid morning hours. There is a low
chance that these storms also impact KSUS, KSTL, and KCPS too,
but confidence is currently greater that they will stay north of
these sites. Yet another round of storms is expected during the
late afternoon and evening along a cold front. These storms will
have the potential to produce hail, erratic strong winds, and
tornadoes. They will be moving quickly, and their window of impact
be much more narrow than the current forecast, which is wider due
to timing uncertainty.

Elmore

&&

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

WFO LSX

Hazardous Weather Outlook
National Weather Service St Louis MO
202 AM CDT Mon Apr 27 2026

ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027-
034>036-041-042-047>052-059>065-072>075-084-085-099-280715-
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-
202 AM CDT Mon Apr 27 2026

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.

Periods of thunderstorms are expected through the day into this
evening. Thunderstorms this afternoon and evening will be capable of
large hail, damaging wind gusts, and tornadoes.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

There is a chance of thunderstorms Tuesday.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to report wind damage, hail occurrence and
size, and tornado occurrence to NWS St. Louis.

Elmore

Preliminary Local Storm Report
National Weather Service St Louis MO
311 AM CDT Mon Apr 27 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0257 AM     Hail             Caledonia               37.76N 90.77W
04/27/2026  M1.75 Inch       Washington         MO   Trained Spotter

&&

Pfahler

Preliminary Local Storm Report
National Weather Service St Louis MO
315 AM CDT Mon Apr 27 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0308 AM     Hail             Irondale                37.84N 90.67W
04/27/2026  M1.25 Inch       Washington         MO   Amateur Radio

&&

Pfahler