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FXUS63 KLSX 141730
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1230 PM CDT Sat Sep 14 2024

.KEY MESSAGES...

- As the remnants of Francine continue to weaken, its influence on
  our area decrease through the weekend. We transition from cloudy
  and cool with a few showers to more sun, warmer, and drier.

- Dry and warm conditions are expected next week.


&&

.SHORT TERM...  (Through Late Sunday Afternoon)
Issued at 230 AM CDT Sat Sep 14 2024

The upper level flow pattern continues to feature a trough over the
western US and a ridge over the east, currently centered near the
Great Lakes. To the south of this ridge, the remnants of Francine
have stalled and weakened over the past few days. As of early
this morning, the center of the surface level circulation was not
well defined but located somewhere just south of Memphis, TN. As
it has weakened it has transitioned more to a mid and upper level
low, with showers and thunderstorms associated with pockets of
vorticity and lift rotating around this low. While the low itself
gradually retreats to the southeast this weekend, the broader
trough axis associated with it shifts westward across our area.
This means that the areas most likely to see a few showers or a
stray thunderstorm from this will gradually shift westward across
our forecast area today and tomorrow. In fact, latest CAMs are in
pretty strong agreement that the area of impact will be to our
west by Sunday, with global scale ensembles supporting this trend
as well. Overall rain chances are decreasing as Francine`s
influence wanes. What rain does fall is likely to be minor and
localized.

Temperatures today and Sunday will be largely dependent on cloud
cover. Where clouds hang on, temperatures stay in the 70s. With more
sun, temperatures warm toward the mid to upper 80s. Satellite
imagery early this morning has already shown considerably more
breaks in the clouds which will support a trend toward more sun than
we saw yesterday, with that trend continuing into Sunday as well.
The warmest temperatures will be in the north and east where
confidence in more sunshine is greater and the influence of the
eastern US ridge is stronger.

Kimble
&&

.LONG TERM...  (Sunday Night through Friday)
Issued at 230 AM CDT Sat Sep 14 2024

The remnant low from Francine continues to weaken and shear out
across the southern US on Monday. In fact, the focus begins to shift
toward a new low developing off the Southeast coast. This leaves us
primarily under the influence of the ridge favoring dry and warm
conditions. NBM does hold on to some low PoP mainly across the
western forecast area on Monday, although this may be overdone if
recent trends continue. The rest of the week remains dry. While
multiple waves eject out of the western US trough, they stay far
enough to our west to have no appreciable impact on our area. The
ridge, and the associated dry and warm conditions, hold on at least
through next weekend. This leads to a relatively high confidence
forecast for much of this week. This confidence is reflected in the
NBM interquartile range for temperatures which remains below 5
degrees all the way through Friday. Look for highs of 85 to 90 each
day with no relief from the developing drought.

Kimble

&&

.AVIATION...  (For the 18z TAFs through 18z Sunday Afternoon)
Issued at 1207 PM CDT Sat Sep 14 2024

The IFR stratus that plagued the central Missouri terminals this
morning scattered out and now a dense diurnal cumulus field is
developing across the region. As the day goes on, this field will
persist but rise and remain VFR before gradually dissipating after
sunset. IFR fog is still forecast at KSUS tonight with humid air
remaining in place, but may need to be expanded if efficient
cooling occurs.

Rain chances creep up in central Missouri tomorrow afternoon, but
thunder chances should be very low. With uncertainty in even rain
developing, no precipitation is mentioned in the TAFs.

MRB

&&

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

$$

WFO LSX