Webster Groves, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

883
FXUS63 KLSX 191726
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1126 AM CST Fri Dec 19 2025

.KEY MESSAGES...

- Up and down temperatures are expected today through Sunday, but
  the big story for this week will be anomalous warmth. In fact,
  all of our local climate sites have a reasonable potential
  (20-50%) to reach or exceed daily record highs on Christmas Day,
  when peak warmth is expected.


&&

.SHORT TERM...  (Through Late Friday Afternoon)
Issued at 150 AM CST Fri Dec 19 2025

Now that yesterday`s round of widespread rainfall in the rear-view
mirror, attention turns to temperatures over the next several days
(and beyond). Temperatures are expected to fluctuate considerably
between today, tomorrow, and Sunday thanks to yet another cold
front, but for the most part this will feature little in the way of
additional precipitation.

While winds remain somewhat gusty across the area late this evening,
speeds are very gradually winding down in the wake of yesterday`s
double-feature cold front. While we may still see a few gusts in the
25 to 35 mph range overnight through early morning, by mid-day
speeds should be rather light area-wide as surface high pressure
moves overhead. Winds may even become southerly by late in the
afternoon, but not quick enough to counter this temporary surge of
cold air. As such, highs today are only expected to reach the 30s
and 40s in spite of an abundance of sun, perhaps only barely
climbing above freezing in the coldest parts of central Illinois
where some stratus may linger a bit longer.

Our up and down temperature trend will resume Saturday and Sunday as
another cold front approaches and moves through the area, with
increasing low-level flow and strong warm advection early in the day
Saturday. This will drive another rapid and temporary warm-up, with
temperatures likely to climb back into the upper 40s to upper 50s in
most areas, perhaps even getting close to 60 in the warmest parts of
the Ozarks. As quickly as this warmup arrives, though, another surge
of cold air will spill into the area Saturday night, resulting in
Sunday temperatures dipping back into the 20s in the morning, and
only rising into the upper 30s/upper 40s during the afternoon. It
will be quite a swing in daily temperatures, and all with near-
zero precipitation chances as well.

BRC

&&

.LONG TERM...  (Friday Night through Wednesday)
Issued at 150 AM CST Fri Dec 19 2025

After this weekend`s temperature volatility, things get a bit
simpler, albeit climatologically unusual from Monday through
Thursday. This is because a steady warming trend will bring well
above average temperatures to the area leading up to Christmas Day,
with a reasonable potential to break daily record highs on the
holiday itself.

The primary driver of weather across the central U.S. will be a
slowly building upper ridge, which is expected to reach 99th+
percentile 500mb heights by Thursday. Meanwhile, south to southwest
flow will also drive persistent warm air advection, particularly
Wednesday and Thursday. Ensemble mean 850 mb temperatures reach very
close to climatological maximums in all of the major ensemble suites
by Thursday, and this is translating to NBM maximum temperature
forecasts in the upper 60s to even low 70s by Christmas Eve and
Christmas Day. Ensemble temperature spreads are also relatively
narrow for this time range, and the most recent run of the NBM
suggests a 50 to 70% chance for temperatures to reach above 70
degrees in most areas south of I-70. You`d have to go all the way to
central Florida to find average highs in a similar range for this
time of year, and we will be well within range of daily records on
Christmas Day as a result.

Meanwhile, the chance for meaningful precipitation remains low for
the next week, although there are some hints of some very light rain
from a subtle shortwave early Monday, followed by very light warm-
advection driven rain or drizzle between late Monday and early
Wednesday. The latter would be most likely across the Ozarks and and
southwest Illinois, although for most areas this pattern is more
likely to produce low clouds rather than measurable rain. Even if
the more bullish ensembles are closer to reality, precipitation
amounts would be very light...on the order of a few hundredths of an
inch.

From Friday onward, long-range ensembles suggest that temperatures
are likely to begin a cooling trend, although forecast spreads do
increase considerably beyond Thursday, leading to much lower
confidence in the day-to-day values. In spite of this, Thursday
(Christmas Day) appears to be the warmest day of the week, and it is
also very likely (80%) that temperatures will remain above average
through at least Saturday.

BRC

&&

.AVIATION...  (For the 18z TAFs through 18z Saturday Afternoon)
Issued at 1124 AM CST Fri Dec 19 2025

Confidence is high in dry and VFR flight conditions. There is a
marginal threat of low level wind shear tonight as the core of a
low-level jet passes over the region, with confidence being
greatest in impacts at KJEF, KSUS, and KUIN. Surface winds will
shift through the day today as high pressure moves across the
region, with another shift expected tomorrow as a cold front sinks
through the region.

Elmore

&&

.CLIMATE...
Issued at 200 AM CST Thu Dec 19 2025

Well above normal temperatures are forecast around Christmas,
with record temperatures within reach. Records for our three
climate sites and the years that they occurred are listed below.

   KSTL  KCOU  KUIN
12/2473(2021)74(2021)69(2021)
12/2571(1889)74(1889)66(2019)


&&

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

$$

WFO LSX