New Haven, Missouri Weather Forecast Discussion

397
FXUS63 KLSX 011939
AFDLSX
Area Forecast Discussion
National Weather Service Saint Louis MO
239 PM CDT Wed Oct 1 2025
.KEY MESSAGES...
- Warm and dry weather continues to be the prevailing forecast
  through the weekend.
- There may be a few isolated showers or possibly a thunderstorm
  Thursday afternoon/evening, primarily across the eastern Ozarks
  into southwest Illinois.
&&
.SHORT TERM...  (Through Late Thursday Night)
Issued at 234 PM CDT Wed Oct 1 2025
The upper level ridge which has been in control of our weather is
drifting east into the Ohio Valley this afternoon.  Water vapor
imagery and upper air analysis is showing a weak short wave trough
to our west over the Great Plains.  Guidance shows this trough
moving east into the ridge and slowly attenuating through Thursday
night.  Yesterday`s 06Z and 12Z GFS runs printed out a few
hundredths of QPF on Thursday and Thursday evening as the short wave
moved across eastern Missouri, however no other models showed precip
potential.  The latest runs of the GFS, RAP, several CAMs and to a
lesser extent the NAM and ECMWF are now showing isolated convection
over parts of the area Thursday afternoon through Thursday night.
Forecast soundings and plan-views show up to 1000-1500 J/Kg of
MLCAPE across parts of southern Missouri Thursday afternoon with
very little cap. However, forecast soundings show very dry air in
the low levels.  It`s possible that only weak showers could form and
that much of the rain would evaporate before hitting the ground.
Regardless, I think a slight chance for precip Thursday afternoon
and evening is warranted across parts of eastern Missouri and
southwest Illinois.  There are some indications that isolated
convection could continue for most of Thursday night, but forcing
looks pretty weak so will limit PoPs to the evening. Temperatures
through Thursday night remain unchanged with lows in the low to mid
60s and highs in the mid to upper 80s.
Carney
&&
.LONG TERM...  (Friday through Next Wednesday)
Issued at 234 PM CDT Wed Oct 1 2025
Mid-upper level ridging builds back over the Mid Mississippi Valley
Friday while another trough digs into the western U.S. Guidance
continues to spit out a few hundredths of QPF here and there over
our area, however given the position of the ridge and apparent lack
of low level forcing, will opt to keep Friday dry at this time.  The
warm and dry forecast for Saturday and Sunday remain steady with the
ridge controlling our weather, however next week`s advertised pattern
shift may be coming a little earlier than previously expected.  A
piece of the western trough ejects across the Plains and through the
Upper Midwest Sunday which attenuates the ridge and allows a cold
front to push into Iowa and possibly Missouri on Monday.  There are
some fairly wide discrepancies with respect to how far southeast the
front will get on Monday.  The GFS pushes the front all the way into
central Missouri by 00Z Tuesday while the EC holds it back across
northern Missouri.  The difference has a large impact on
precip chances and temperatures Monday across northeast Missouri into
west central Illinois.  The LREF`s interquartile range of
temperatures jumps from only 2 degrees in Knox County MO on Sunday
to 12 degrees Monday obviously indicating a very low degree of
certainty in the forecast.  The LREF members are more confident
that the front won`t make it to St. Louis or farther southeast as
the range of highs drops to 2 to 4 degrees.  It does look like the
front will eventually make it through the area as forecast highs
drop into the  70s by Wednesday.  Unfortunately precip chances
remain low through the end of the period despite the flow aloft
becoming quasi-zonal and the front becoming nearly stationary
oriented east-west across southern Missouri or northern Arkansas.
The low PoPs are likely due to a general lack of low level moisture
due to a blocking ridge axis south of the front along the Gulf Coast.
Carney
&&
.AVIATION...  (For the 18z TAFs through 18z Thursday Afternoon)
Issued at 1229 PM CDT Wed Oct 1 2025
VFR flight conditions and light southeast flow is expected to
prevail through the period.
Carney
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX

NWS LSX Office Area Forecast Discussion