355
FXUS63 KLSX 022342
AFDLSX

Area Forecast Discussion
National Weather Service St Louis MO
542 PM CST Mon Nov 2 2026

.KEY MESSAGES...

- Breezy conditions and widespread showers and isolated
  thunderstorms are expected ahead of a cold front late
  tonight into Tuesday.

- Cooler, but seasonable temperatures are expected the rest of
  the week with mostly dry conditions.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 1233 PM CST Mon Nov 2 2026

As of noon today broad high pressure was centered over the Mid
Atlantic while a potent surface low was tracking northeast through
eastern South Dakota. Our area has remained in a moist southeast low
level flow with plenty of low clouds keeping a lid on temperatures
today. A cold front extends SSW from the surface low down through
western Kansas with a secondary surface low developing in Kansas and
tracking ENE tonight into Tuesday. The increasing pressure gradient
between the high to the east and the approaching front will lead to
breezy winds developing this afternoon and lasting through the
night. This combined with plenty of cloud cover will keep
temperatures balmy overnight, mostly in the 60s. Thunderstorms, some
severe, are expected to develop in the Plains ahead of the front
this evening with the remnants of this activity reaching our western
forecast area border shortly before sunrise on Tuesday. This should
be elevated and shallow in nature by the time it reaches our area,
limiting any severe weather threat.

As the front pushes east across our area on Tuesday we expect
widespread showers and isolated thunderstorms to continue in the
moist advection ahead of the front. The environment ahead of the
front will be increasingly sheared as a 50+ KT southwesterly jet at
850MB overspreads the low level southeasterlies. Instability,
though, looks meager at best. Although with the arrival of the
trough aloft we do lose low level capping, lapse rates remain weak
and what instability does develop has limited vertical depth. Among
the 12Z HREF guidance, less than 50 percent of members produce
surface based CAPE of 300 or higher. That has increased relative to
the 00Z guidance, but it is primarily behind the initial line of
convection. Thus the greater severe weather threat, to the extent
that it exists, may be with any secondary attempt at convection
along the front itself in the afternoon. If surface based convection
can form in this environment, the strong low level shear suggests
weak tornadoes are possible. In addition, any stronger downdrafts
could help push stronger winds from the low level jet down to the
surface.

&&

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
Issued at 1233 PM CST Mon Nov 2 2026

Rain comes to an end Tuesday night as the front and associated mid
level trough push eastward. The air mass behind the front has spent
the last several days modifying over the desert southwest, so it
won`t be appreciably cold by the time it gets here. However, we will
see temperatures some 10 degrees cooler for highs on Wednesday
compared to ahead of the front on Tuesday. Additional mostly dry
cold fronts later in the week provide modestly better shots of
colder air, but not extreme by seasonal standards. In fact, by this
weekend NBM probability of freezing temperatures increases to 10 to
40 percent across the region, favoring the colder rural valley
locations. Nearly all locations in our forecast area are well behind
their average first freeze, so if we are able to get a clear, calm
night in a cold air mass we could finally see that occur.

&&

.AVIATION /00Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 542 PM CST Mon Nov 2 2026

Ceilings are expected to remain or continue rising to MVFR this
evening thanks to some stronger winds. These winds will slowly
become strong overnight and into the morning, with gusts nearing 30
kts not out of the question. A band of showers will move into
central MO in the early morning hours on Tuesday, and slowly
progress east through the region during the day. The timing and
intensity of the showers remains uncertain, but they are expected to
impact visibilities to MVRF, or possibly IFR at times. There is a
slight chance (~20%) that there could be thunderstorms associated
with this band of showers, but confidence is low that these could
impact the terminals.

&&

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

&&

$$

SHORT TERM...Kimble
LONG TERM...Kimble
AVIATION...Asel/Britt