Prices Branch, Missouri Weather Forecast Discussion

704
FXUS63 KLSX 271901
AFDLSX
Area Forecast Discussion
National Weather Service Saint Louis MO
201 PM CDT Sat Sep 27 2025
.KEY MESSAGES...
- Peak temperatures are expected tomorrow through Tuesday, with
  highs likely in the mid to upper 80s and low humidity.
- No rain is expected for the next week.
&&
.SHORT TERM...  (Through Late Sunday Night)
Issued at 158 PM CDT Sat Sep 27 2025
Our slow warming trend continues today as high pressure remains in
control of the Mississippi River valley. Satellite imagery reveals a
weak trough moving through the Great Lakes, with a trailing cold
front extending into Iowa early this afternoon. However, this
front is expected to wash out before it reaches our area, and
will not impact our local weather conditions. Temperatures will
likely top out in the low to mid 80s in another hour or two as a
result.
Overnight, another round of clear skies and nearly calm winds are
likely to produce another round of river valley fog, thanks in part
to the relatively warm water temperatures in our larger rivers
(Missouri and Mississippi Rivers). The coverage of this fog may be
slightly reduced thanks to the extra day of sun and deep mixing, but
we will likely see at least some fog once again overnight. This will
impact only limited areas, but some valleys may see localized
visibility reductions to near 1/4 mile at times.
BRC
&&
.LONG TERM...  (Monday through Next Saturday)
Issued at 158 PM CDT Sat Sep 27 2025
Temperatures are expected to peak tomorrow through Tuesday as
surface high pressure continues to build into the area, and an upper
level ridge both amplifies and moves directly overhead. While
temperatures are likely to reach the mid to upper 80s, perhaps even
near 90 degrees, this will fall well short of daily records and
low humidity will prevent heat from reaching truly impactful
levels. Still, high temperatures will likely reach nearly 10
degrees above average over the next few days, with morning lows
closer to average thanks to efficient radiative cooling.
From Wednesday onward, some subtle changes to the upper pattern are
likely to bring temperatures down a few degrees, although still
perhaps not quite to "average". Previous forecasts had hinted at the
potential for tropical moisture to retrograde into our area from the
Bahamas as the ridge shifts slightly farther northeast. However,
these solutions continue to fade from the already limited number
of ensemble members, and this continues to look less and less
likely. While we do continue to see a signal for increasing cloud
cover over the latter half of the work week and a slight drop in
temperatures, the potential for rain remains very low for the next
week.
Instead, we will likely need to wait until at least next weekend
before we see another reasonable opportunity for rain, which is when
ensembles finally begin to break down the upper ridge. Still, even
this is very tenuous at that time range, and the signal for
precipitation is highly variable.
BRC
&&
.AVIATION...  (For the 18z TAFs through 18z Sunday Afternoon)
Issued at 1151 AM CDT Sat Sep 27 2025
VFR conditions and light winds can be expected for a majority of
the 18Z TAF cycle. Once again, the primary concern will be the
potential for redeveloping valley fog along the Missouri and
Mississippi Rivers, which has impacted JEF, SUS, and CPS to
varying degrees over the past two mornings. While coverage may be
somewhat reduced compared to this morning, fog will once again be
possible at each of these terminals overnight and early tomorrow
morning. Otherwise though, no additional weather hazards are
expected.
BRC
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX

NWS LSX Office Area Forecast Discussion