Old Jamestown, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

089
FXUS63 KLSX 071015
AFDLSX

Area Forecast Discussion
National Weather Service St Louis MO
515 AM CDT Fri Aug 7 2026

.KEY MESSAGES...

- Showers and thunderstorms are expected mainly south of I-70
  today, but coverage is uncertain along with their ability to
  produce additional heavy rainfall/flash flooding.

- Heat and humidity is expected to return to the region this
  weekend into early next week. Heat headlines might be
  required.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 221 AM CDT Fri Aug 7 2026

Today: The latest 850 mb analysis shows a low level jet (LLJ)
axis oriented southwest to northeast across central Missouri.
Along the front edge of this LLJ, thunderstorms have formed and
are moving northeast. Further development is possible to the
west as the core of the LLJ strengthens, but this will be
transient as the LLJ weakens near sunrise. Another area of
convection being closely watched is across central Kansas. This
convective complex is forecast to slowly move southeast this
morning and weaken. By late this morning into early afternoon a
remnant MCV is likely to be located near south/ southwest
Missouri. As the MCV approaches south/ central Missouri in the
late afternoon, showers and thunderstorms are likely to form
(~60%) as the atmosphere destabilizes. Latest high res guidance
is inconsistent on the location, speed, and trajectory of the
MCV. Confidence is slightly higher here than normal with summer
convection though, as a weak surface boundary was analyzed
across south/ central Missouri which is likely to be what the
MCV anchors to. The greatest threat from these storms will be
heavy rainfall or localized strong wind gusts. The overall
severe threat looks low as SFC - 6 km shear values remain around
10 kts. Expect high temperatures in the mid 80s to near 90
degrees. Simultaneously, convection will form ahead of a
tightening trough axis over central Iowa this afternoon. The
wave will head east though, so am expecting the convection in
Iowa to head southeast and rapidly weaken.

Saturday: Missouri will mostly be under weak upper level
subsidence on Saturday with the area remaining dry. Expect high
temperatures mostly in the upper 80s.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Issued at 221 AM CDT Fri Aug 7 2026

For the second half of the weekend, high temperatures will begin
to reach the mid 90s with dewpoints creeping back into the mid
70s. This is thanks to high pressure over the southwestern
United States slowly expanding east with mid-level heights
rising. A weak cold front will also stall over southern
Minnesota helping low level moisture to pool (e.g., rising dewpoints).
It currently looks like heat products will be needed starting
Sunday and persisting into Tuesday before relief arrives. Little
precipitation is expected Sunday and Monday.

Wednesday into Thursday, the mid-level ridge begins to weaken
with heights falling across Missouri. Multiple rounds of showers
and thunderstorms will be possible.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 508 AM CDT Fri Aug 7 2026

The showers and thunderstorms from earlier this morning have
progressed east with very weak returns to the south and west of
the St. Louis Terminals. These weak showers will be transient
and are not expected to affect the terminals. Some brief
restrictions at KUIN this morning are possible given dewpoint
depressions nearing zero. However, wind remains out of the east
around 6 kt, so any visibility restrictions this morning will
likely not last long.

All attention then turns to the convection currently ongoing
over Kansas. These storms are forecast to move southeast this
morning and approach south/ central Missouri. If the convection
is able to become organized over Kansas this morning an MCV
could form. If an MCV does form, it could serve as an impetus
for the development of showers and thunderstorms just south of
the Columbia and St. Louis terminals. This scenario is rather
low confidence, therefore have left any mention of afternoon
thunderstorms or showers out of the TAFs.

&&

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

&&

$$

SHORT TERM...BAH
LONG TERM...BAH
AVIATION...BAH