641
FXUS63 KLSX 011930
AFDLSX

Area Forecast Discussion
National Weather Service Saint Louis MO
230 PM CDT Mon Jun 1 2026

.KEY MESSAGES...

- Dry weather with low humidity and near to below normal
  temperatures are expected through Thursday.

- Chances (30-60%) of showers and thunderstorms return to the
  region beginning Friday.


&&

.SHORT TERM...  (Through Late Tuesday Afternoon)
Issued at 229 PM CDT Mon Jun 1 2026

GOES-19 visible satellite imagery shows the western edge of the
remnant outflow boundary associated with this morning`s convection
draped from far south-central Missouri southeast to near Memphis,
TN as of 1900 UTC. This feature should serve as the focused for
renewed convective development over the next few hours. Storms
should move east/southeast with time, and may clip far southern
sections of the CWA (Reynolds/Iron). Further north, isolated
showers and (weak) thunderstorms may develop in/near a backdoor
cold front. This front is not well-defined from a wind
perspective, but there probably will be just enough convergence
to help initiate convection in a region of moderate instability
(1000-2000 J/kg SBCAPE). Any remaining showers/thunderstorms
should quickly dissipate near/just after sunset with loss of
diurnal instability. Dry weather along with slightly cooler and
less humid air will then infiltrate the region behind the backdoor
cold front overnight as low-level northeasterly flow increases.


Gosselin

&&

.LONG TERM...  (Tuesday Night through Next Monday)
Issued at 229 PM CDT Mon Jun 1 2026

(Tuesday - Thursday)

Dry weather will continue through midweek along with near (daytime
highs) to below (nighttime lows) normal temperatures and low
humidity. The incoming air mass is pretty noteworthy for early June,
with a ~1028 hPa surface high (near record strength) Tuesday evening
centered across the Great Lakes. Temperatures at 850 hPa still look
more modest, but do drop closer to the +10 to +12C range, or 2 to 5C
below normal. Finally, surface dewpoints are expected to be in the
upper 40s to low 50s parts of both Tuesday and Wednesday, which
would be close to the 10th percentile of climatology. While a mostly
clear sky will certainly help temperatures drop overnight into the
low to mid 50s, sunshine will also play its part by helping highs
climb to near the 80 degree mark through Wednesday. Some moderation
is expected to begin by Thursday as forecast highs are expected to
climb back into the low to mid 80s.


(Thursday Night - Next Monday)

Ensemble guidance is in good agreement with the general mid/upper
level flow pattern across the CONUS late this week into the weekend,
showing a mid/upper level ridge gradually weakening and shifting
east/southeast into the Tennessee Valley. Weak troughing is also
forecast to move across the US-Canadian border region, with a cold
front draped southwest from a surface low. This front is still
expected to move southeast into the bi-state area. The boundary
should tend to stall out across the mid-Mississippi Valley, with
continued chances (30-60%) of showers and thunderstorms into early
next week.


Gosselin

&&

.AVIATION...  (For the 18z TAFs through 18z Tuesday Afternoon)
Issued at 1239 PM CDT Mon Jun 1 2026

There may be a few isolated showers/weak thunderstorms along a
backdoor cold front, though coverage looks too low to add any
mention in the TAFs. Diurnal cumulus bases will be below 3 kft AGL
for a couple more hours, but should be mostly FEW-SCT.
Light/variable winds should turn more out of the northeast behind
the front this evening - Tuesday.

Gosselin

&&

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

$$

WFO LSX