840
FXUS63 KLSX 222021
AFDLSX

Area Forecast Discussion
National Weather Service Saint Louis MO
221 PM CST Fri Nov 22 2024

.KEY MESSAGES...

-Dry weather is expected through the weekend with moderating
 temperatures.

-Temperatures are expected to turn colder for Thanksgiving week.
 There is chance of rain Wednesday into Thursday with the
 possibility of snow mixing in.

&&

.SHORT TERM...  (Through Late Saturday Night)
Issued at 215 PM CST Fri Nov 22 2024

The low clouds have persisted across the area today in the low level
cyclonic flow.  There have been some breaks showing up in the
visible satellite imagery, but areas that don`t clear out late this
afternoon could very well stay cloudy tonight because of the long
nights this time of year.  The HREF is showing the low level flow
turning out of the southwest late tonight into tomorrow which will
lead to the clouds breaking up from west to east late tonight into
tomorrow morning.  The HREF probabilities continue to favor dry
weather through Sunday as an upper ridge builds into the area.

Lows will drop to near normal tonight with the coolest readings over
central and southeast Missouri where it is most likely to clear out.
Highs on Saturday will be near normal with skies clearing out and
winds turning out of the west and then climb back above normal on
Sunday with southwesterly low level flow and 850mb temperatures
climbing to around +10C.

Britt

&&

.LONG TERM...  (Sunday through Next Friday)
Issued at 215 PM CST Fri Nov 22 2024

We will go into a more active pattern next week leading up to
Thanksgiving.  There is still agreement in model guidance that a
cold front will move through the CWA on Monday and that this front
will stay south of the area the rest of the week.  This front will
bring a chance (20-40%) of rain as it moves across the area Sunday
night into Monday.

There will be strong cold air advection behind this front with lows
falling below normal the rest of the week.  It now looks like the
Monday night through Tuesday night will be dry before a second upper
trough will approach the area from the Rockies. I have kept with the
NBM`s precipitation chances Wednesday through Thanksgiving Day has
the upper trough moves through the area. This is when some of the
operational models are showing good synoptic forcing setting up
across Missouri and Illinois including a coupled jet and mid level
frontogenesis. NBM and LREF precipitation probabilities are
favoring the best chances (50-60%) over southeast Missouri and
southern Illinois on Wednesday night, but this system is several
days out and may very well shift to north or south as the forecast
becomes clearer in the next few days. The LREF does have some
members that are producing snowfall with this second system and
the latest NBM probabilities showing about 20-30% chance of
snowfall Wednesday night into Thursday over parts of the CWA.

Britt

&&

.AVIATION...  (For the 18z TAFs through 18z Saturday Afternoon)
Issued at 1059 AM CST Fri Nov 22 2024

Cloud cover with MVFR and some low VFR ceilings continues to
affect all of the terminals at midday and now is not is expected
to move out of COU/JEF until after 00Z and at UIN/STL/SUS/CPS
until after 12Z on Saturday morning. The ceilings at UIN will
likely stay below 2000 feet AGL until at least mid morning on
Saturday morning. Otherwise, dry weather is expected through the
period with northwest winds into tonight before turning light and
backing to the southwest on Saturday morning.

Britt

&&

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

$$

WFO LSX