textproduct: Springfield

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.