Flash Flood Warning 20, NWS St. Louis, MO

258 
WGUS73 KLSX 031410
FFSLSX

Flash Flood Statement
National Weather Service St Louis MO
910 AM CDT Wed Jul 3 2024

MOC071-073-139-183-189-219-031530-
/O.CON.KLSX.FF.W.0020.000000T0000Z-240703T1530Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Franklin MO-Gasconade MO-Montgomery MO-Saint Charles MO-Saint
Louis MO-Warren MO-
910 AM CDT Wed Jul 3 2024

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1030 AM CDT THIS 
MORNING FOR FRANKLIN, GASCONADE, SOUTHWESTERN MONTGOMERY, 
SOUTHWESTERN SAINT CHARLES, SOUTHWESTERN SAINT LOUIS AND SOUTHERN 
WARREN COUNTIES IN EAST CENTRAL MISSOURI...

At 910 AM CDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 2.5 and 5 inches of rain have 
fallen. Additional rainfall amounts up to 1 inch are possible in the 
warned area. Flash flooding is ongoing or expected to begin shortly.

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...
  Chesterfield, Wildwood, Ballwin, Maryland Heights, Manchester, 
  Washington, Town and Country, Union, Eureka, Ellisville, Pacific, 
  Valley Park, Weldon Spring, St. Clair, Fenton, Owensville, 
  Clarkson Valley, Hermann, New Haven and Villa Ridge.

This includes the following State Parks...
Babler Memorial State Park, Route 66 State Park, Castlewood State 
Park and Robertsville State Park.

This includes Interstate 44 in Missouri between exits 239 and 272.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 3870 9154 3871 9133 3863 9115 3867 9096
      3871 9065 3871 9052 3851 9046 3850 9059
      3847 9062 3849 9065 3848 9066 3846 9065
      3845 9067 3848 9073 3842 9074 3833 9101
      3829 9164 3871 9164

FLASH FLOOD...RADAR INDICATED

$$

Pfahler

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
638 AM CDT Wed Jul 3 2024

.KEY MESSAGES...

- The combination of heat and humidity will allow heat index
  values to climb to around 105 degrees over parts of southeast
  Missouri where a Heat Advisory is in effect this afternoon into
  early this evening.

- There will be additional rounds of thunderstorms through
  Thursday night. A few of the storms could be severe this
  afternoon and this evening and again on Thursday afternoon and
  evening.

- In addition to the severe weather potential, locally heavy
  rainfall is possible with these thunderstorms.

&&

.SHORT TERM...  (Through Late Thursday Afternoon)
Issued at 422 AM CDT Wed Jul 3 2024

Highs will reach the lower 90s over southeast Missouri and dewpoints
are forecast to be in the mid to upper 70s over much of the area.
Peak heat index readings will reach around 105 over parts of
southeast Missouri, so I have issued a Heat Advisory for Reynolds,
Iron, and Madison counties from 11 am through 8 pm today.

I have gone ahead and canceled the flood watch early as the heavy
rainfall threat has ended over the northern CWA.  We are continuing
to see showers and thunderstorms over the central part of the CWA
early this morning.  These were occurring on the nose of the LLJ and
they should gradually weaken and move east over the next few hours
as the LLJ veers and weakens.  The associated outflow boundary will
move south into the southern part of the CWA this afternoon.  The
most likely time for additional thunderstorm development today will
be this afternoon over southeast Missouri into southwest Illinois
along this effective front where MLCAPES will be 2500+ J/kg with
deep layer shear of 30+ knots.  This could is favorable for
producing a few organized multicell clusters that could produce
damaging winds through early this evening.

The coverage of showers and thunderstorms will increase across the
area late this evening and overnight as a shortwave trough
approaches the area and the low level jet kicks back warranting 60-
90% PoPs.  We are still looking at PWATS between 2-2.5" and very
high warm cloud depths, and the HREF LPMM has some small spots with
with totals exceeding 3" tonight into tomorrow morning.  Will
continue to look at the potential for locally heavy rainfall tonight
into early Thursday.

Then there will be another risk for severe thunderstorms Thursday
afternoon and evening as yet another shortwave trough move across
the area where the warm front will intersect the incoming cold
front.  The combination of CAPE/shear favors a few supercells/
organized multicells capable of producing damaging winds and large
hail.

Britt

&&

.LONG TERM...  (Thursday Night through Tuesday)
Issued at 422 AM CDT Wed Jul 3 2024

Available guidance is still favoring the front moving through the
area on Thursday night with showers and thunderstorms moving out of
the southeastern part of the CWA on Friday.  Friday night into
Saturday look dry as large surface high moves across the area.  The
next upper trough moves through the area early next week bringing a
chance of showers and thunderstorms as early as Sunday.

Britt

&&

.AVIATION...  (For the 12z TAFs through 12z Thursday Morning)
Issued at 633 AM CDT Wed Jul 3 2024

Complex of showers and thunderstorms currently affecting the St.
Louis area terminals is expected to move out of the terminals by
14Z. Low clouds with MVFR and IFR ceilings will affect UIN/COU/JEF
through 17Z. There will be the chance for additional showers and
thunderstorms through the day into the evening, but coverage will
be too low to include in the TAF. A better chance for
thunderstorms will occur later this evening and overnight with the
potential for MVFR and and IFR ceilings and visibilities in heavy
rain.

Britt

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...Heat Advisory from 11 AM this morning to 8 PM CDT this evening
     for Iron MO-Madison MO-Reynolds MO.

IL...None.
&&

WFO LSX

Hazardous Weather Outlook
National Weather Service St Louis MO
502 AM CDT Wed Jul 3 2024

ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027-
034>036-041-042-047>052-059>065-072>075-084-085-099-041015-
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-
502 AM CDT Wed Jul 3 2024

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.

There is a chance of thunderstorms over the region through tonight. A
few of these storms could be severe mainly across southeast Missouri
into southwest Illinois this afternoon and early this evening.
Damaging winds will be the primary threat. Locally heavy rainfall
will also be possible this afternoon and tonight.

Heat index values today will climb to around 105 degrees over parts
of southeast Missouri where a Heat Advisory is in effect.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

There is a chance of thunderstorms Thursday through Friday and again
through Tuesday. A few of these storms could be severe on Thursday
afternoon and evening over parts of central, east central, and
southeast Missouri. Damaging winds and large hail will be the primary
threats.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed this afternoon over parts of
southeast Missouri and southwest Illinois.

Britt

Preliminary Local Storm Report
National Weather Service St Louis MO
621 AM CDT Wed Jul 3 2024

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

0607 AM     Flood            3 NNW Columbia          38.99N 92.35W
07/03/2024                   Boone              MO   Emergency Mngr

            Approximately 8-12 inches of water flowing
            over N Creasy Spring Road north of the Cow
            Branch stream.

&&

Maples

Preliminary Local Storm Report
National Weather Service St Louis MO
635 AM CDT Wed Jul 3 2024

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

0612 AM     Rain             1 SSE Saint Paul        38.84N 90.73W
07/03/2024  M2.05 Inch       St. Charles        MO   Trained Spotter

&&

Maples

Preliminary Local Storm Report
National Weather Service St Louis MO
638 AM CDT Wed Jul 3 2024

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

0528 AM     Flood            3 W Centralia           39.21N 92.20W
07/03/2024                   Boone              MO   911 Call Center

            Long Branch stream flooded over E Highway CC
            and Tri-City Road.

&&

Maples

Preliminary Local Storm Report
National Weather Service St Louis MO
714 AM CDT Wed Jul 3 2024

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

0705 AM     Rain             1 E Clarkson Valley     38.63N 90.57W
07/03/2024  M2.26 Inch       St. Louis          MO   Broadcast Media

            Report courtesy of KTVI-TV.

&&

Maples

Preliminary Local Storm Report
National Weather Service St Louis MO
723 AM CDT Wed Jul 3 2024

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

0430 AM     Rain             2 NNW New London        39.62N 91.42W
07/03/2024  M1.53 Inch       Ralls              MO   CO-OP Observer

            CO-OP Observer station NLDM7 2.4 NW New
            London.

&&

CS

Preliminary Local Storm Report
National Weather Service St Louis MO
727 AM CDT Wed Jul 3 2024

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

0715 AM     Rain             1 S Cottleville         38.74N 90.65W
07/03/2024  E2.51 Inch       St. Charles        MO   Public

&&

CS