Flash Flood Warning 11, NWS St. Louis, MO

974 
WGUS73 KLSX 171138
FFSLSX

Flash Flood Statement
National Weather Service St Louis MO
638 AM CDT Sun Jul 17 2022

ILC027-121-171315-
/O.CON.KLSX.FF.W.0011.000000T0000Z-220717T1315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Clinton IL-Marion IL-
638 AM CDT Sun Jul 17 2022

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 815 AM CDT THIS 
MORNING FOR NORTHEASTERN CLINTON AND WEST CENTRAL MARION COUNTIES IN 
SOUTH CENTRAL ILLINOIS...

At 638 AM CDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 2 and 4 inches of rain have 
fallen. The expected rainfall rate is 1 to 2 inches in 3 hours. 
Additional rainfall amounts of 1 to 2 inches are possible in the 
warned area. Flash flooding is ongoing or expected to begin shortly.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar.

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...
  Salem, Sandoval, Odin, Fairman, Shattuc, Boulder, Tonti, Junction 
  City, Alma, Selmaville, Brubaker and Ferrin.

This includes the following highways...
	Interstate 57 in Illinois near exit 116.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 3874 8923 3874 8921 3874 8918 3874 8917
      3874 8914 3874 8909 3872 8884 3860 8885
      3858 8911 3858 8914 3858 8924

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...1-2 INCHES IN 3 HOURS

$$

MRM

968 
WGUS73 KLSX 171305
FFSLSX

Flash Flood Statement
National Weather Service St Louis MO
805 AM CDT Sun Jul 17 2022

ILC027-121-171315-
/O.EXP.KLSX.FF.W.0011.000000T0000Z-220717T1315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Clinton IL-Marion IL-
805 AM CDT Sun Jul 17 2022

...FLASH FLOOD WARNING WILL EXPIRE AT 815 AM CDT THIS MORNING FOR 
NORTHEASTERN CLINTON AND WEST CENTRAL MARION COUNTIES IN SOUTH 
CENTRAL ILLINOIS...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

LAT...LON 3874 8923 3874 8921 3874 8918 3874 8917
      3874 8914 3874 8909 3872 8884 3860 8885
      3858 8911 3858 8914 3858 8924

$$

MRM

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1104 PM CDT Sat Jul 16 2022

.UPDATE...
Issued at 950 PM CDT Sat Jul 16 2022

Everything still looks on track at this time for an MCS to impact
the area late in the overnight period and into Sunday. Thus far we
have seen some sprinkles and scattered light showers across
central and eastern MO in association with a weak short wave and
attendant area of mid level moisture. We have also seen isolated-
scattered thunderstorms across parts of southeast MO and southwest
IL in the vicinity of a pre-frontal trof where some of the most
unstable air resides and there is weak large scale ascent with the
aforementioned short wave. The one remaining storm has recently
exited the CWA.

Overnight it still looks like an MCS should evolve from northwest
into north-central MO in response to lift and cooling aloft
associated with the next upstream short wave, and moisture
convergence and lift with the southwesterly LLJ. The only thing
that looks a tad different in the latest short-term guidance is
the onset may be just slightly later. The breadth of the LLJ and
distribution of instability along and north of the frontal zone
suggests the MCS should have an elongated west-east structure as
it spreads east-southeast across northeast and east-central MO and
into western IL into the early morning hours. The main heart of
the MCS should exit east by 15-18z, although there could be
trailing west-east showers and storms lingering into afternoon.
The system configuration would support the potential for echo
training/repeat convection and locally heavy rain. While I don't
think the longevity of heavy rain will be great on a widespread
basis, there could be some localized spots that see some pretty
decent amounts and the 12Z HREF 24h QPF PPM was suggesting some
small corridors of 3-4+ inches. Given how dry it has been and the
drought conditions, FFG values show most locations could handle
this over 3-6 hours, however if it occurs in a shorter time frame
then we could see some isolated flooding issues.

Glass

&&

.SHORT TERM...  (Through Late Sunday Night)
Issued at 321 PM CDT Sat Jul 16 2022

A series of 500 mb shortwaves is moving into the Midwest from the
north. At the surface, a cold front is draped east-west across
northeast Missouri and west-central Illinois. While our CWA is
seeing dewpoints in the mid-60s, dewpoints north of the front are in
the 70s as well as dewpoints south of the forecast area. As the
front sags south, the moisture from the north will spill into our
area. The moisture south of our area will also ride into the CWA
along southwesterly flow. This will result in moisture convergence
on top of our region along the front. The presence of the upper
level shortwave, surface front, and moisture convergence has the
potential to spur the development of scattered showers and
thunderstorms this afternoon. However, a limiting factor to
thunderstorm development is the substantial but weakening cap that
will be in place for the majority of the area this afternoon.

A secondary shortwave will move into the region Saturday evening,
providing another source of ascent for showers and thunderstorms.
The coverage of showers and thunderstorms will increase through
Saturday night and into Sunday morning due to multiple sources of
ascent in the forms of the shortwave, surface convergence from the
cold front, and a low level jet over central Missouri. Early Sunday
morning is the best window to see heavy rainfall as moisture over
our CWA will be the most abundant. By Sunday evening, the second
shortwave and cold front will be moving out of the CWA. Showers and
thunderstorms will become isolated in nature before ending Monday
morning.

MUCAPE values of 1000-2000 J/kg will promote the development of
elevated thunderstorms tonight. 0-6 km wind shear isn't as
impressive, with values struggling to reach 30 kts across much of
the area. With these parameters in place, the potential for
isolated, disorganized severe weather. The most likely threats will
be hail and damaging winds. Widespread rain is expected with this
event as slow moving sources of ascent pair with precipitable water
values of up to 2 inches. Most places will see at least 0.5 inches
of rain with some places seeing locally heavy rainfall amounts.
According to high resolution guidance, some locations may see up to
4 inches of rain. If this falls in an urban area, isolated flash
flooding could occur. However, as dry as the region has been this
summer, much of the rain we will receive will be beneficial, and the
potential for widespread flooding is low with this event.

Jaja

.LONG TERM...  (Monday through Next Saturday)
Issued at 321 PM CDT Sat Jul 16 2022

Upper level ridging will build into the area after the system exits
on Monday morning. High pressure near the surface will build in the
southeast U.S. Southerly winds on the western flank of the high will
usher in warm, dry conditions to our region. Since humidity will be
lower, heat index values for Tuesday and Wednesday should not climb
very far above actual temperatures. Nevertheless, heat index values
will climb to near 105 degrees Tuesday for much of the area, but
will be limited to the southern CWA Wednesday as a cold front pushes
through. Brief relief will come Thursday with the cold frontal
passage, but temperatures will warm again as ridging builds in again
Friday and Saturday.

Jaja

&&

.AVIATION...  (For the 06z TAFs through 06z Sunday Night)
Issued at 1058 PM CDT Sat Jul 16 2022

KUIN: MVFR flight conditions are expected through much of the
forecast period, initially due to ceilings. We are still expecting
a large and persistent complex of showers and thunderstorms to
develop overnight beginning around 09z. Flight conditions with
the showers and storms will be predominately MVFR although could
drop to IFR at times. The main area of showers and storms should
move to the east by 18z.

KCOU and KJEF: In the near term, short-lived light showers and VFR
flight conditions are expected. However beginning around 09z a
large and persistent complex of showers and thunderstorms is
expected to develop and impact the terminal. Flight conditions
with the showers and storms will be predominately MVFR although
could drop to IFR at times. The main area of showers and storms
should move to the east by 15z.

KSTL/KSUS/KCPS: A spot light shower or sprinkle and VFR flight
conditions is expected through around 09z. Between 09-10z, a
large and persistent complex of showers and thunderstorms is
expected to develop and impact the terminal. Flight conditions
with the showers and storms will be predominately MVFR although
could drop to IFR at times. The main area of showers and storms
should move to the east by 18z.

&&

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

WFO LSX

Hazardous Weather Outlook
National Weather Service St Louis MO
234 PM CDT Sat Jul 16 2022

ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027-
034>036-041-042-047>052-059>065-072>075-084-085-099-171945-
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-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-
234 PM CDT Sat Jul 16 2022

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

.DAY ONE...Tonight.

Widespread thunderstorms are expected across the area, mainly during
the late night hours.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

Showers and thunderstorms are likely to continue through early
Monday for portions of the region.

It is looking increasingly likely that dangerous heat will return to
portions of the area on Tuesday and Wednesday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

BSH