textproduct: Springfield

KEY MESSAGES

- A Heat Advisory is in effect through Saturday. Highs near 100 with Heat Index values 100-105 can be expected. Daily records may continue to be tied or broken. - Less than 20% chance for isolated showers and storms this afternoon, particularly across the eastern Ozarks and south- central Missouri.

- Cooler conditions with scattered rain chances arrive early next week. Details on the exact extent of the cooldown and location of the highest rain chances remain uncertain at this time.

SHORT TERM /THROUGH SATURDAY/

Issued at 110 PM CDT Fri Sep 18 2026

Synoptic and Mesoscale Overview:

The Missouri Ozarks remain squarely under a prominent upper- level ridge as a cutoff low spins over the northwestern CONUS. A quasi- stationary front sits across northern Missouri attached to a weak surface low in the northern Plains. Early afternoon obs show dew points in the mid 60s across far southern Missouri with values closer to 70 degrees across central Missouri. Satellite shows the developmental stage of a fairly muted cumulus field over the region at this point.

Heat Continues:

The hot, stagnant air under the ridge combined with the moderate to high dew points will produce afternoon heat index values between 100-105 degrees once again today and tomorrow. It should be noted that the NBM has consistently been about 2-3 degrees too cool in its forecast maximum temperatures the last several days. Given little change in the synoptic regime, persistence forecasting should prove useful, so we have once again nudged temperatures upward, and they will once again challenge daily records. See the Climate section below for more info. The Heat Advisory remains in effect areawide through 8 PM Saturday.

Isolated Storms Today:

Afternoon heating should continue to agitate the cu field and result in attempts at convective initiation. The slightly lower dew points across far southern Missouri may prevent much from firing or getting too robust for these locations; the greatest chances may manifest for locations along and north of I-44 and east of Hwy 65 where the deeper moisture is present. Indeed, CAMs tend to favor this area in simulated reflectivity. A lack of appreciable shear will support a pulse-type storm mode. Although coverage should be sparse, RAP output suggests vertical totals approaching 30 C may support an isolated downburst wind gust threat up to 60 mph. Most if not all activity will remain sub- severe, however.

LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/

Issued at 110 PM CDT Fri Sep 18 2026

Widespread Rain Chances Sat Night - Mon:

Global models depict the ridge breaking down on Saturday as the aforementioned low shifts east. As it does so, the attendant surface front will slog through the Plains and into northwestern Missouri. Destabilization and convergence will produce showers and thunderstorms along and ahead of the boundary. With the slow speed of the front, rain chances will increase across the northwestern CWA late Saturday night and gradually translate to the east-southeast throughout the day Sunday and finally move out on Monday. It should be stated, however, that all day washouts are not expected as convection may strengthen and diminish multiple times within this slow-moving system. Overall, the greatest rainfall totals are forecast north of I-44 where the greatest PWATs and deepest moisture will be, but the higher totals will likely be quite localized.

NBM Probabilistic Rainfall (Sat Night thru Mon): >0.10 inch: 50-70% >0.25 inch: 40-60% >1.00 inch: 10-25%

Cooler Temperatures Early Next Week:

Yes, the cold front will indeed bring cooler temperatures to the region early next week. With the continued slower trend of the frontal passage on Sunday, it remains possible that an extension of the Heat Advisory will be needed across southern Missouri for an additional day, but questions on timing, temperatures, dew points, and convective coverage limit confidence too greatly to make that determination with this forecast package.

After Sunday, confidence is high that temperatures will decrease. There remains a moderate amount of uncertainty in exactly how much cooler they will be, however, with ensemble clusters continuing to show disagreement in just how much the ridge gets dampened. That said, the NBM interquartile range would support near-average high temperatures for much of the area on Monday (near 80 deg) and even *below-average* temperatures by Tuesday. Again, details like frontal timing, cloud cover, and convective coverage will ultimately drive the temperatures any one location will experience, but the signal for comparatively cooler temperatures is clear.

AVIATION /00Z TAFS THROUGH 00Z MONDAY/

Issued at 532 PM CDT Fri Sep 18 2026

VFR conditions are likely through the TAF period. A few isolated showers and storms have developed across central and eastern Missouri but will diminish at the beginning of the TAF period and remain northeast of the terminals.

Southwesterly winds will increase after 12Z Saturday, particularly across far western Missouri where gusts of 20 kt will be possible.

CLIMATE

Issued at 309 AM CDT Fri Sep 18 2026

Record High Temperatures:

September 18: KSGF: 95/2019 KJLN: 97/2022 KVIH: 95/1953 KUNO: 96/1972

September 19: KSGF: 96/1954 KJLN: 99/2024 KUNO: 97/1954

September 20: KSGF: 97/1954 KVIH: 95/1954 KUNO: 97/1954

Record High Minimum Temperatures:

September 18: KSGF: 74/1931

September 19: KSGF: 73/1931

September 20: KSGF: 74/2018

SGF WATCHES/WARNINGS/ADVISORIES

KS...Heat Advisory until 8 PM CDT Saturday for KSZ073-097-101. MO...Heat Advisory until 8 PM CDT Saturday for MOZ055>058-066>071- 077>083-088>098-101>106.