Severe Thunderstorm Warning 164, NWS St. Louis, MO

Area Forecast Discussion
National Weather Service Saint Louis MO
358 AM CDT Mon Jun 1 2026

.KEY MESSAGES...

- There will be two rounds of thunderstorms today, one early this morning
  and another over southeast Missouri and southwest Illinois this
  afternoon. Damaging winds, large hail, and heavy rainfall are
  possible with the strongest storms.

- Dry weather is expected Tuesday through Thursday before the
  chances for showers and thunderstorms returns later this week
  into next weekend.

&&

.SHORT TERM...  (Through Late Tuesday Afternoon)
Issued at 356 AM CDT Mon Jun 1 2026

Thunderstorms continue to show a gradual increase in intensity
and severity early this morning on the nose of a broad low level
jet across Missouri. There remains the potential for severe
thunderstorms the remainder of the morning as the thunderstorms
over central and western Missouri develop a cold pool which could
cause upscale growth across the CWA into a line segment bringing
some damaging winds and hail with the stronger storms given the
current 1000-2500 MLCAPES and effective shear of 30-40 knots. The
environment this morning also remains favorable for storm
producing heavy rainfall given the current PWATS and warm cloud
depths, particularly if they can train in any one location for
very long.

The CAMS including the HRRR have this first round of convection
moving through the CWA by around 9-10 am.  It will lay out of the
outflow boundary that will allow for additional shower and
thunderstorm development this afternoon.  RAP soundings from
Farmington this afternoon are showing MLCAPES between 2000-3000 J/kg
with around 30 knots of deep layer shear.  This should be sufficient
to to produce an isolated threat for damaging winds and large hail
into the early evening hours.

Drier weather is expected from mid evening on as the HREF is showing
the high building down the upper Midwest.  Highs today will recover
back into the 80s behind this morning's storms but should be a few
degrees cooler tomorrow with cold air advection.
Britt

&&

.LONG TERM...  (Tuesday Night through Sunday)
Issued at 356 AM CDT Mon Jun 1 2026

Dry weather is still expected Wednesday into Thursday as the upper
ridge moves south across the area.  As the ridge continues to move
to the south, the chance of showers and thunderstorms will return to
the area late this week into the weekend as moisture returns north
into the area ahead of western trough.  High temperatures are
expected to return into the mid to high 80s.

Britt

&&

.AVIATION...  (For the 06z TAFs through 06z Monday Night)
Issued at 1106 PM CDT Sun May 31 2026

The focus for impacts this period continues to be showers and
thunderstorms through this morning. The main corridor for these
showers and thunderstorms will stretch from near KCOU and KJEF
east-southeastward through KSUS, KSTL, and KCPS. KUIN has a low
chance of being grazed by this activity, though confidence in this
occurring is dwindling. Storms will be capable of heavy rainfall
that will reduce visibilities to MVFR and even IFR flight
categories, and there is a very low chance for gusty, erratic
winds and small hail at KCOU and KJEF. Showers and thunderstorms
will move south of the local terminals by mid morning, with
confidence high in VFR flight conditions through the remainder of
the day.

Elmore

&&

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

WFO LSX