Plevna, Missouri Weather Forecast Discussion

106
FXUS63 KLSX 050335
AFDLSX
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1035 PM CDT Thu Sep 4 2025
.KEY MESSAGES...
- Another cold front will move through the area late tonight into
  Friday morning. Areas of rain are expected in the colder air
  behind the front, mainly in the afternoon and evening.
- Dry weather and below normal temperatures are expected through
  Monday.
&&
.SHORT TERM...  (Through Late Friday Night)
Issued at 246 PM CDT Thu Sep 4 2025
Another short wave trough is diving into North Dakota and Wisconsin
this afternoon on the western side of a deep long wave trough
anchored by a closed low over Canada`s Ontario Province.  A surface
low is developing ahead of the wave on the South Dakota/North
Dakota/Minnesota border.  This low will move east, dragging another
cold front behind it down into the Mid Mississippi Valley by 12Z
Friday.  The front briefly becomes stationary near the
Missouri/Arkansas border late Friday morning/early afternoon before
another short wave kicks it through Friday afternoon/evening. Short
range guidance shows weak to moderate moisture convergence across
the southern half of Missouri and Illinois Friday north of the
surface front.  Mid-level frontogenesis also develops near the I-70
corridor during the late afternoon into the early evening ahead of
the second short wave.  All models kick out QPF to a greater or
lesser extent in response to this forcing on Friday, with the
highest amounts generally along and south of I-70.  All that said,
only light to occasionally moderate rain is expected, and QPF
amounts will be light, well under 1/2 inch in most cases.  The
clouds and precip will suppress afternoon temperatures, particularly
north of I-70 where highs will likely struggle into the 65-70 degree
range.  Rain will end from northwest to southeast Friday night as
drier air filters into the region.
Carney
&&
.LONG TERM...  (Saturday through Next Thursday)
Issued at 246 PM CDT Thu Sep 4 2025
A sprawling surface high will build across the Central U.S. behind
the front on Saturday.  This will be the dominant surface feature at
least through Tuesday as it drifts east across the Ohio Valley/Great
Lakes Region into New England.  This translates cool and dry weather
for the Mid Mississippi Valley for the weekend into early next week.
 Another short wave digs into the base of the long wave trough
Saturday/Saturday night which will push a secondary, reinforcing
cold front through Missouri and Illinois by 12Z Sunday morning.
Therefore Sunday may be a degree or two cooler than Saturday, but
highs are expected to be 5-10 degrees below normal in the low to mid
70s at most locations both days.  Sunday and Monday morning in the
mid 40s to around 50 will be as much as 10-15 degrees below normal.
Temperatures will moderate as the center of the surface high moves
east of the Mississippi Valley and the wind turns back to a
southerly direction.  Above normal temperatures are expected by
Tuesday, and Wednesday and Thursday are forecast to be well above
normal.  With that in mind, nailing down the highs gets more
difficult during that time frame as the pattern becomes more
amplified.  A strong upper ridge builds over the Great Plains and
Midwest late Wednesday into Thursday.  This should amp up the
warming trend, however LREF cluster analysis is showing variability
in both the position and amplitude of the ridge.  This variability
shows up in the temperature forecast as the interquartile range of
high temperatures is 9-10 degrees both days.  The deterministic
NBM`s highs are near the 75th percentile of the range.  The mid 80s
to around 90 high temperatures it`s forecasting are believable due
to the forecast strong ridge.  However my confidence in those
numbers isn`t particularly high at this time.
Carney
&&
.AVIATION...  (For the 06z TAFs through 06z Friday Night)
Issued at 1008 PM CDT Thu Sep 4 2025
A cold front will shift winds to northwesterly this morning.
Throughout the day, rain will filter through the forecast area.
The best chances for rain will be generally along and south of
I-70 this afternoon into early this evening. Maintained prevailing
-RA at the Mid-Missouri and STL metropolitan terminals, though
 rain may track a bit further south than previously expected. Some
 brief MVFR cigs may accompany showers mainly in central MO, but
 confidence in them occurring for any significant length of time
 is decreasing.
Jaja
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX

NWS LSX Office Area Forecast Discussion