615
FXUS63 KLSX 160735
AFDLSX

Area Forecast Discussion
National Weather Service Saint Louis MO
235 AM CDT Mon Sep 16 2024

.KEY MESSAGES...

- It`ll be another warm day today with isolated showers and
  thunderstorms this afternoon. This is the last meaningful
  opportunity for rain this week.

- Dry and warm weather lasts at least through the end of the
  workweek.

&&

.SHORT TERM...  (Through Late Tuesday Afternoon)
Issued at 230 AM CDT Mon Sep 16 2024

The upper air pattern across North America is dominated by a broad
ridge of high pressure across the central and eastern portions of
the continent, along with a deep trough over the West Coast. To the
south of the eastern ridge a broad trough axis persists although it
is reorganizing. The old core of this trough continues to spin
across Arkansas, but further to the east a tropical low has
developed and will soon become the dominant low. The National
Hurricane Center expects to upgrade this to a Tropical Storm soon,
before it makes landfall in the Carolinas later today. At the
surface, high pressure centered offshore of New England extends
its influence westward into the Great Lakes maintaining an
easterly flow across our region. This flow has brought
progressively drier air into our area over the past few days and
this trend continues again today. This drier air should limit the
coverage of showers and thunderstorms this afternoon relative to
the past few days. In fact, this should be the last day that we
see any chance of rain as the remnant upper low to our south gets
fully absorbed by the new developing low to its east.

With drier air moving in from the east, we`ll see a subtle drop in
low temperatures tonight and Tuesday night relative to the past few
nights as the dry air allows for a lower floor for temperatures in
good cooling conditions. Daytime highs remain consistently in the
mid to upper 80s with considerably less cloud cover once the
influence of this upper low departs.

Kimble

&&

.LONG TERM...  (Tuesday Night through Sunday)
Issued at 230 AM CDT Mon Sep 16 2024

The tropical system moving into the southeast US will move into the
Appalachians and stall, spinning there for several days. Our area
will be in between this stalled low to our east and the persistent
trough in the West, leaving us in relative ridging. That spells dry
and warm conditions through at least the end of the week with highs
each day reaching well into the 80s or even low 90s.

We do start to see some low thunderstorm chances (20 to 40 percent)
creep into western parts of our forecast area this weekend. This is
a result of multiple embedded waves ejecting out of the Western US
trough this week gradually inching closer to our area. Still,
though, the best forcing associated with these waves stays to our
west and north as ridging developing over the Southern Plains
deflects this energy around us. For this reason we expect the dry
trend to continue for most of the region which will only allow the
developing drought to persist and intensify.

Kimble

&&

.AVIATION...  (For the 06z TAFs through 06z Monday Night)
Issued at 1037 PM CDT Sun Sep 15 2024

Fog with LIFR visibilities and ceilings has develops at SUS and
CPS. Have IFR visibilities through 13Z with a tempo group for 1/2
mile or less through 10Z, but these visibilities may last through
13Z. There is a also some potential for fog late tonight at JEF in
the river valley.  Otherwise, isolated thunderstorms will be
possible over southeast and central Missouri on Monday afternoon,
but the chance is too low to include at JEF/COU at this time.
Otherwise, expect dry and VFR conditions with light winds.

Britt

&&

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

$$

WFO LSX