405
FXUS63 KSGF 210702
AFDSGF

Area Forecast Discussion
National Weather Service Springfield MO
202 AM CDT Tue Jul 21 2026

.KEY MESSAGES...

- A Heat Advisory is in effect until 7 PM today, with heat index
  values between 100 to 110 degrees. The hottest conditions will
  occur across extreme southern Missouri and southeast Kansas.

- Low-confidence thunderstorm risk this afternoon. The Storm
  Prediction Center has outlined portions of south-central
  Missouri and the eastern Ozarks in a Marginal Risk (Level 1 of
  5) for an isolated wind gust up to 60 mph.

- Seasonable temperatures mid to late week, with rain chances
  returning late Thursday into Friday.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 202 AM CDT Tue Jul 21 2026

Synoptic Overview:

An upper-level shortwave trough over eastern Canada and the
Great Lakes region was impinging upon the eastern periphery of
an expansive ridge covering much of the western and central
CONUS early this morning. The corresponding surface low in
Ontario features an occluded front extending to its south with a
trailing cold front wrapping to the southwest across southern
Iowa and northern Missouri, which has been the focus for strong
to severe convection.

Hot and Humid Today:

Mid-level height rises will support temperatures climbing even a
bit warmer today than yesterday. In fact, NBM mean temperatures
support highs approaching the 100 degree mark across extreme
southern Missouri and southeast Kansas. Furthermore, the
stagnant airmass will support continued high dew points that
will result in unseasonably hot and humid conditions.

The fly in the ointment will be the aforementioned cold front
that will push south through the region today. Temperatures will
increase rapidly ahead of the front during the morning, likely
reaching or exceeding 90 degrees by 10-11 AM for most locations.
This will allow heat indices to climb quickly as well. Model
guidance, however, has trended toward a faster/earlier frontal
passage, which will act to cap the amount of heating across
central Missouri--roughly along and north of Highway 54--
producing maximum afternoon indices closer to 100 degrees. While
the cooler temperatures will actually lag behind the front/wind
shift by several hours, forecast soundings depict a strong
mixing signal behind the boundary. That is, temperatures will
remain high through the afternoon, but heat indices will either
level off or even slightly decrease.

On the other end of the spectrum, locations across extreme
southern Missouri and southeast Kansas will have more time
ahead of the front during peak heating hours, which will allow
temperatures to climb within the humid airmass. Therefore, heat
indices will tend to increase the farther south you look. Here,
maximum heat indices between 105 to 110 degrees will be more
common. Low-lying, sheltered areas protected from vertical
mixing will tend to measure higher dew points as well. Furthermore,
the northerly wind shift will result in downsloping winds on
the south side of the Ozark plateau, which will have a net
warming effect.

All this to say that we would not be surprised if localized
areas south of Highway 60 reached or even slightly exceeded a
110 degree heat index for an hour or two. However, most of these
locations are expected to remain between a 105 to 109 degree
heat index; thus, the Heat Advisory has been maintained.
Whether your maximum heat index is closer to 100 degrees or 110
degrees, it will still be quite hot, and individuals who will be
outdoors for an extended time period today should have cooling
and hydration options readily available.

Low-Confidence Thunderstorm Risk this Afternoon:

The frontal passage within a highly moist and unstable
environment (as much as 3000-4000 J/kg MUCAPE!) will provide the
lift for possible convective initiation this afternoon. Shear
will be modest and perhaps a bit too late to arrive for
sustained, organized convection in our area, but given the ample
instability combined with 0-3 km theta-e differences of 25-30
deg C, a few strong to severe downdrafts capable of producing
straight line wind gusts up to 60 mph will be possible. Models
continue to be of little help when it comes to building forecast
confidence, however, as they exhibit little run-to-run or
model- to- model consistency. Fortunately, human science says
there is at least some risk for isolated robust convection along
the cold front across the eastern Ozarks and extreme south-
central Missouri, so 15-25% PoPs have been added. To that end,
SPC has expanded its Marginal Risk westward into portions of
Oregon, Shannon, and Howell counties with their 06Z update.

&&

.LONG TERM /WEDNESDAY THROUGH TUESDAY/...
Issued at 202 AM CDT Tue Jul 21 2026

Cooler and a much less humid airmass will move in behind the
cold front Tuesday night into Wednesday. Afternoon high
temperatures will be closer to 80 degrees across central
Missouri and the eastern Ozarks but closer to 90 degrees across
extreme southwest Missouri and southeast Kansas; regardless,
much lower dew points around 60 degrees will make it feel much
more comfortable than the heat of late. These relatively cooler
conditions will persist through Friday, followed by a warming
trend through the weekend. After previously large NBM
temperature spreads on Friday, guidance has trended toward a
cooler solution with increasing confidence in showers and
thunderstorms.

To that end, global models begin to flatten the ridge as
another shortwave trough moves through the area late Thursday
which brings the next chances for rain into Friday morning.
Rain chances have increased across the board, now between 40 to
70%, with the highest chances across central Missouri.

For the weekend and beyond, ensemble clusters have exhibited
slightly better agreement in the evolution of the upper-level
pattern with general consensus in maintaining the ridge across
the western/central CONUS, but important differences still
remain. With the ridge axis to the west, there typically is not
a screaming, widespread precipitation signal in the guidance
this far out, but it does leave the door open to the passage of
shortwave impulses on the eastern periphery of the ridge that
could result in rain chances here in southwest Missouri and
southeast Kansas. Any potential would have to be better
assessed in future forecast packages. Otherwise, PoPs remain
less than 20% areawide Saturday afternoon through Tuesday.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1130 PM CDT Mon Jul 20 2026

VFR conditions are likely through the TAF period. There is a low
chance that a few isolated showers or thunderstorms develop
along a cold front this afternoon across extreme southern
Missouri, but confidence in occurrence was too low to include
in the TAFs (<20% chance). If storms did form, the SGF and BBG
terminals would be the most likely to be impacted.

Winds will prevail out of the south-southwest early this morning
before eventually shifting to the north behind the
aforementioned cold front in the afternoon.

&&

.SGF WATCHES/WARNINGS/ADVISORIES...
KS...Heat Advisory until 7 PM CDT Tuesday for KSZ073-097-101.
MO...Heat Advisory until 7 PM CDT Tuesday for MOZ055>058-066>071-
     077>083-088>098-101>106.

&&

$$

SHORT TERM...Didio
LONG TERM...Didio
AVIATION...Didio