Mehlville, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

610
FXUS63 KLSX 180938
AFDLSX

Area Forecast Discussion
National Weather Service Saint Louis MO
338 AM CST Sat Jan 18 2025

.KEY MESSAGES...

- Temperatures will remain steady or fall into the 20s and 30s
  today. Wind chills will drop below zero over much of the area
  late tonight and Sunday morning with high temperatures in the
  teens and 20s Sunday through Tuesday.

&&

.SHORT TERM...  (Through Late Sunday Afternoon)
Issued at 337 AM CST Sat Jan 18 2025

Regional radar is showing the area of light rain across southeast
Missouri and southwest Illinois continuing to move east, and the
CAMS are still showing it exiting the CWA by sunrise.  The latest
surface analysis is showing that a cold front extends from roughly
Decatur to St. Louis to Rolla with the RAP moving it south of the
CWA by sunrise. There will be strong CAA today along with lingering
cloud cover which will cause falling or near steady temperatures.
Highs will be 20 to 30 degrees cooler compared to yesterday.  Lows
tonight will drop into the single digits and teens while highs
tomorrow across most of the area will stay in the teens.  Wind
chills late tonight into Sunday morning will be below zero across
most of the CWA.

Once the rain moves out the area early this morning, the rest of the
day is expected to be dry.  The NAM/GFS is showing an upper trough
dropping out of the northern Plains today and moving across
Missouri/Illinois tonight.  Forecast soundings are still showing a
shallow layer of moisture that combined with the ascent caused by
the trough warrants keeping the chance of flurries across southeast
Missouri and southwest Illinois tonight.

Britt

&&

.LONG TERM...  (Sunday Night through Friday)
Issued at 337 AM CST Sat Jan 18 2025

There is high confidence that we remain below freezing Sunday night
through Tuesday as all of the ensembles in cluster analysis are
showing a deep longwave trough over the central CONUS early next
week.  The 850mb temperatures will be in the -15 to -25 range as a
surface high moves down into Missouri and Illinois by Monday.  This
high will linger over the area into Tuesday which will supply decent
radiational cooling both Monday and Tuesday mornings.  The LREF
probabilities are still showing a 40-70 percent chance of AOB
-10F apparent Ts early on Monday and Tuesday mornings along and
north of I-70 which means there is still some potential need for a
Cold Weather Advisory early next week.  The cluster analysis by late
next week is beginning to show some spread with the majority of the
members showing a more zonal flow versus one that is still showing a
deeper trough over the eastern CONUS.  The more progressive flow
supports the going forecast of moderating temperatures with highs
climbing back above freezing Wednesday into Friday.

The deterministic and ensemble mean models bring a upper trough and
attendant front across the area late in the week.  The GFS/Canadian
are depicting some spotty, light QPF with this, but will keep the
forecast dry as even the 10th percentile of the NBM is dry through
next week over the CWA. This matches up well with the the number of
the ensembles in the LREF where greater than 90 percent of them are
dry.

Britt

&&

.AVIATION...  (For the 06z TAFs through 06z Saturday Night)
Issued at 1112 PM CST Fri Jan 17 2025

The rain and MVFR conditions are expected to stay south of the
terminals through the period leaving dry and VFR conditions
through the period. Winds will turn out of the northwest early in
the period and will gust at times to 20 to 25 knots.


Britt

&&

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

$$

WFO LSX