Webster Groves, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

142
FXUS63 KLSX 060739 CCA
AFDLSX

Area Forecast Discussion
National Weather Service Saint Louis MO
139 AM CST Sat Dec 6 2025

.KEY MESSAGES...

- The temperature this weekend and into next week bounces between
  seasonably mild and bitter cold and back again.

- Precipitation chances this weekend have decreased compared to
  earlier forecasts. Significant precipitation is not expected
  through the middle of next week.


&&

.SHORT TERM...  (Through Saturday Night)
Issued at 136 AM CST Sat Dec 6 2025

A cold front has begun to slip into our region from the north early
this morning. It won`t make it very far south before stalling around
midday. It will, however, serve to stunt the recent milding
temperatures in the north, with highs only making it into the 30s
generally across the still snow covered half of the forecast area.
Further south it will be another somewhat mild day by recent
standards, though still a few degrees below normal.

A quick moving trough exits the Northern Rockies and moves southeast
into the Plains today, then crosses the Mississippi River tonight.
The southerly flow ahead of this trough pushes the remnant front
back to the north as a warm front overnight, with the surface low
tracking near the Iowa/Missouri border. This further north track
compared to prior forecasts limits our precipitation potential with
this wave, as the bulk of the precipitation falls in bands north of
the warm front roughly from Des Moines to Chicago. Any precipitation
we get out of it will be from warm advection in the warm sector
south of the front. This will be less organized and warmer. So
expect a few sprinkles or rain showers overnight, but not much more
than that. The best potential for snow remains across the far
northern fringes of the forecast area, but even here chances have
decreased significantly due to the shift in track further north.
Among the 12Z low resolution ensemble guidance, less than 50 percent
of members now produce measurable snowfall at Quincy. None of the
high resolution guidance does so.

Kimble

&&

.LONG TERM...  (Sunday through Thursday)
Issued at 136 AM CST Sat Dec 6 2025

A much colder air mass will be pulled southward behind Sunday`s
wave. In fact, some areas may see falling temperatures Sunday
afternoon with temperatures bottoming out in the teens and single
digits by Monday morning. The surface high associated with this air
mass crosses through our area on Monday, so after one more cold day,
we see a dramatic warm up in southwesterly flow behind the high for
Tuesday. NBM probability of 50 degrees has increased compared to
yesterday`s forecast, with most areas south of I-70 in Missouri at
50 percent or better chance of reaching that threshold. That`s a
good 15 to 20 degrees warmer than Monday.

The next significant trough moves through the Upper Midwest into the
Great Lakes Tuesday into Wednesday. Once again this wave tracks to
our north, limiting our precipitation chances with it. If we do get
anything it will be rain as we will be solidly in the warmer air by
that point. However, this trough does once again send a cold front
southward behind it with a sharp cool down expected for the end of
the week. There continues to be rather large spread in guidance on
just how cold we get, but there`s strong agreement that we do get
cold. The NBM interquartile range for high temperatures rises to
about 15 degrees Thursday and Friday indicating that much higher
uncertainty. However, it`s worth noting that while that spread
ranges from the upper 20s to mid 40s for highs on Thursday, it drops
10 degrees for Friday, ranging from the upper teens to the mid 30s
for highs. Lows have similar levels of uncertainty on them, with NBM
probability of subzero lows rising to as high as 30 percent in our
northern forecast area.

While Wednesday`s wave passes by to our north while we`re still in
the warmer air, guidance is starting to come into some alignment on
the idea of a secondary wave coming down in the northwest flow
behind it on Thursday while we`re in the freshly colder air. There`s
a lot of timing and track variance still, but most guidance does now
show this wave in some form. This will serve as our better chance of
wintry precipitation, most likely in the form of light snow,
provided this wave tracks through our area. Among the 12Z low
resolution ensemble guidance, 50 percent or more of members produce
measurable snowfall in the 24 hours ending Thursday evening, and
even the deterministic NBM forecast is beginning to reflect this
with 20 to 30 PoPs.

Kimble

&&

.AVIATION...  (For the 06z TAFs through 06z Saturday Night)
Issued at 1107 PM CST Fri Dec 5 2025

An MVFR cloud deck with bases around 2500ft agl is moving
southeast out of Iowa, and will overspread the area through the
remainder of the night. The western edge of the MVFR which is
moving into parts of central Missouri is a little higher between
3000-3500ft, but bases will probably fall through the night.
Guidance suggests that ceilings across northeast Missouri and
west central Illinois will fall to IFR by around 12Z and will take
until early afternoon to lift to MVFR. The low ceilings should
lift and scatter by around 18Z across the remainder of the area.

Carney

&&

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

$$

WFO LSX