textproduct: Springfield

KEY MESSAGES

- Heat ramps back up today and through the end of the week, with a Heat Advisory in effect from 1 PM to 8 PM this afternoon/evening.

- Marginal (Level 1 of 5) to Slight (Level 2 of 5) Risk of severe storms very late tonight into Wednesday morning as a storm complex moves through central Missouri, with damaging winds being the primary severe hazard.

- Marginal (Level 1 of 5) to Slight (Level 2 of 5) Risk of severe storms again Wednesday evening/night as another storm complex develops across southern Missouri. Damaging winds are the primary severe hazard, though hail and tornadoes could be possible if the ingredients align properly.

- Excessive rainfall leading to flooding will be possible with any/all storms between tonight and Thursday morning.

SHORT TERM /THROUGH TONIGHT/

Issued at 243 AM CDT Tue Aug 18 2026

Synoptic analysis shows the upper level ridge over the western CONUS, with an upper low pivoting southeast towards Manitoba/Ontario, Canada and its associated upper level trough pushing through the northern Plains. This is placing the forecast area in northwesterly flow aloft. Surface high pressure still resides over the region, with satellite imagery showing mostly clear skies (other than some mid to high level clouds over far southern MO) and observations depicting temperatures ranging in the 60s (much of the area) to low 70s (far southern MO).

Southerly flow returns today, with a warm front attached to a surface low over Kansas lifting into the southwest portion of the area. This will usher in a hot airmass to the area once again, leading to highs in the upper 90s to low 100s for areas generally southwest of a Nevada to Springfield to West Plains line. Areas northeast of that line remain in the low to mid 90s. With heat index values ranging between 100-110 degrees, a Heat Advisory goes into effect for portions of far southeast KS and far southwest MO from 1PM -8PM this afternoon and evening.

Later tonight, an upper level shortwave is progged to push across northern MO, with an MCS developing along the nose of a nocturnal LLJ. Latest CAMs show storms initiating northwest of the area over northeast KS/northwest MO before developing into a slightly more organized cluster as they approach our northern counties. Assessing the environment, guidance shows 0-6km Bulk Shear of 40-50kts over Central MO and about 30-35kts over our northern forecast area, with maximum MUCAPE between 1000-1500 J/kg. The current trajectory looks to push storms southeast through the northeast portion of the CWA overnight beginning as early as 1AM. The environment does look to weaken the further southeast these storms push, which is represented in the latest SPC Outlook. The Slight (2 of 5) risk was pushed back northeast, with it only nudging into Vernon/St. Clair/Benton counties now, with the Marginal (1 of 5) risk along/north of a Pittsburg to West Plains line. Damaging winds of 60-70mph look to be the primary hazard, with hail up to quarters as a secondary risk. Localized heavy rainfall will also pose a flooding risk, especially with training storm potential. HREF LPMMs show localized pockets of 2-3" over our northeast counties, so we'll need to monitor for flash flooding with these storms.

LONG TERM /WEDNESDAY THROUGH MONDAY/

Issued at 243 AM CDT Tue Aug 18 2026

Wednesday looks to bring a large range in afternoon highs, with areas north of Highway 60 remaining between 85-95 degrees, and areas south of the highway climbing between 95-105. If this occurs, then heat index values would once again climb between 100-110 degrees, and the heat advisory would need to be extended through Wednesday. There's still much uncertainty in how the overnight convection will influence temperatures, so there's low confidence in those higher temps being fully realized. Because of that, decided to hold off on extending the Advisory into Wednesday for now, but can't rule out a future extension in later packages.

The aforementioned shortwave trough will move out of the Plains and towards the Mid Mississippi/Ohio Valleys during the day on Wednesday. Periodic showers/storms are possible (20-30%) throughout the day, however the better chances (50-70%) for storms exist in the evening and overnight. The Storm Prediction Center has highlighted the southeast portion of the CWA in a Slight risk (2 of 5), as this area will see the greater instability (1000-2000 J/kg MUCAPE) and shear (0-6kt bulk shear of 40-50kts). The primary hazard with these storms will once again be damaging winds, however if key mesoscale features can line up, all modes will be possible, meaning a lower-end tornado and hail threat.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 533 AM CDT Tue Aug 18 2026

VFR conditions should prevail through the TAF period. Surface winds continue to shift out of the south this morning, generally remaining below 10kts. Towards the end of the period, a system will push through central MO bring showers and storms, however this activity looks to remain well north of the terminals, with precipitation chances <15%. LLWS will begin to ramp up at all three sites, generally between 06Z-09Z, persisting through the remainder of the period.

SGF WATCHES/WARNINGS/ADVISORIES

KS...Heat Advisory from 1 PM this afternoon to 8 PM CDT this evening for KSZ073-097-101. MO...Heat Advisory from 1 PM this afternoon to 8 PM CDT this evening for MOZ066-077-088-093-101>104.