453
FXUS63 KLSX 021952
AFDLSX

Area Forecast Discussion
National Weather Service Saint Louis MO
252 PM CDT Tue Jun 2 2026

.KEY MESSAGES...

 - Mild, dry, and comfortable conditions persist through early
   Thursday with near normal daytime highs (upper 70s to low-80s)
   and seasonably cool lows (50s to low-60s).

- Temperatures gradually warm Thursday and Friday (low to
  mid-80s), then remain slightly above normal (mid to upper 80s)
  through early next week. Warmth will coincide with increasing
  chances for showers and thunderstorms.


&&

.SHORT TERM...  (Through Late Wednesday Night)
Issued at 242 PM CDT Tue Jun 2 2026

Quiet conditions are expected across the region through the short
term period with no concern for impacts at this time.

The axis to an upper level ridge extends from just south of the
Hudson Bay, bookended by troughing over the eastern and western
CONUS. Visible satellite shows extensive cloud cover originating
from the central Plains, sending high clouds eastward into parts of
Missouri. Broad mid-level to surface ridging is stacked below the
upper ridge with anticyclonic flow pulling dry air in from the east
and northeast. Anticyclonic flow continues to impede the eastern
extent of cloud cover through Wednesday with dewpoints largely in
the 50s. Partly to mostly sunny skies are favored with surface wind
speeds following diurnal trends: At or less than 10 mph out of east
and southeast during the day and light/variable at night. Clear
skies and light winds allow for efficient cooling overnight with
seasonably cool nighttime temperatures.

NBM spreads are remarkably tight with only 1-3 degrees between the
IQR. There is high confidence in the near term forecast with near
normal daytime highs (upper 70s to low-80s) and seasonably cool
morning lows (low to mid-50s).Maples

&&

.LONG TERM...  (Thursday through Next Tuesday)
Issued at 242 PM CDT Tue Jun 2 2026

Dry conditions persist into the early portion of the long term
period. Temperatures begin to warm gradually later in the week,
coinciding with increasing chances of showers and thunderstorms as
we head into the upcoming weekend.

The upper level ridge becomes less amplified and slides eastward
along with the surface high late Wednesday into Thursday. Southerly
return flow results in modest mid-level warming as H8 temperatures
rise from the low to mid-teen to the mid and upper teens from
Thursday into Friday. This trend continues over the weekend into
early next week as NBM temperatures maintain a relatively small
spread between IQRs (4-6 degrees), tacking on a degree or two each
day through Sunday, then remaining relatively flat going into next
week. This leads to relatively high confidence in temperature
trends through the weekend, barring locally-driven impacts
stemming from precipitation chances. Showers and thunderstorms
look to arrive sometime between late Thursday and Friday
afternoon as the eastward drift in the ridge. However, this is
where the hang-up is in the finer spatial/temporal details.
Whether the ridge maintains enough influence to hold convective
trends to the west or more quickly shifts east will impact arrival
time. Multi- run 6-hourly QPF data among the global ensembles
(GFS/ECM) is in relatively good agreement with measurable
precipitation coming in late Thursday night into Friday morning.
Unfortunately, both ensemble suits center over the weekend, when
multi-run 6-hourly data yields roughly 0.05-0.20" from Friday
night through Sunday, potentially extending into next week. LREF
25th/75th percentiles show a wide range (0.25-1.25") in QPF totals
Friday into Monday with the highest amounts over central Missouri.
This highlights the spread in QPF potential as the surface ridge
exhibits less influence in time.

While there is greater confidence in the general temperatures
trends, much of this relies on precipitation and resulting cloud
cover. Precipitation patterns and trends remain less certain with
convective potential best supported in an axis of higher CAPE values
that line the western side of the ridge. Essentially, what is
currently presented over the central Plains makes and eastward shift
into the Mississippi Valley. This is motivated by an upper trough
that progresses west to east across the northern U.S., which
sends a cold front northwest to southeast from the northern Plains
into the mid-Mississippi Valley. CAPE probs are not all that well
aligned considering the largely low-flow state of the atmosphere
and resulting focus in thunderstorms. At least some rain is
possible (40-60%) over the weekend, but spatial and temporal
extent is less certain given the progression of the pattern.

Maples

&&

.AVIATION...  (For the 18z TAFs through 18z Wednesday Afternoon)
Issued at 1209 PM CDT Tue Jun 2 2026

High pressure over the Great Lakes will maintain dry, easterly
flow through the period. There is high confidence in VFR
conditions persisting through Wednesday afternoon.

Maples

&&

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

$$

WFO LSX