textproduct: Springfield

KEY MESSAGES

- Heat ramps back up on Tuesday and through the end of the week, with a Heat Advisory in effect on Tuesday from 1 PM to 8 PM.

- Marginal (Level 1 of 5) to Slight (Level 2 of 5) Risk of severe storms very late Tuesday night 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 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 Tuesday night and Thursday morning.

SHORT TERM /THROUGH TONIGHT/

Issued at 140 PM CDT Mon Aug 17 2026

Current Conditions & Synoptic Overview:

High pressure is building across the region in the wake of a cold front that moved through the area last night. The region is in northwest flow in the mid-levels as the persistent ridge of the last week has been broken down, though ridging is re- developing across portions of the Intermountain West.

Today/Tonight:

High clouds are across the area this afternoon as a result of storms to our south in Arkansas along the cold front. This, paired with the NW flow aloft, is helping to keep temperatures much cooler this afternoon, with temperatures early this afternoon only in the mid-80s. As afternoon mixing increases, winds could intermittently gust up to 20 mph this afternoon, but would decrease after sunset. Dew points in the mid-60s this afternoon will help it feel less muggy today than the last several days. Skies should clear overnight, and lows in the 60s may result in some patchy fog in the eastern portions of our forecast area.

LONG TERM /TUESDAY THROUGH MONDAY/

Issued at 400 PM CDT Mon Aug 17 2026

Heat:

A plume of southwesterly winds push back across the Central Plains towards our area ahead of lee cyclogenesis in western Kansas on Tuesday, bringing back warm air to the region. A warm front should start pushing into our area from the southwest by Tuesday afternoon, increasing our temperatures back into the 90s areawide. Far western and southern portions of our area will likely breach 100 degrees, bringing heat indices back into the 105-110 degree range for Tuesday. For that reason, our Kansas counties and the far western tier of our Missouri counties as well as some of our Missouri counties along the Arkansas border have been added to a new Heat Advisory from 1 PM to 8 PM on Tuesday. Depending on the speed and timing of the warm front, it is possible an eastward expansion of the Advisory may be needed in subsequent forecast packages.

The presence of convection during the day on Wednesday will have implications on temperatures (and thus heat indices) and whether or not areas reach Heat Advisory criteria again on Wednesday. It is likely to be a similar area to Tuesday where heat indices may meet or exceed 105 degrees on Wednesday, especially if convection remains confined to areas east of Interstate 49 as is currently expected. This uncertainty prevented Heat Advisory issuance for Wednesday at this point, though it may or may not need to be added in coming days. Additional heat concerns continue through the week, with the four days of 100+ heat indices criteria potentially being met in the western and southern portions of our area, leading to the potential for additional Heat Advisory issuance through at least Friday. However, Tuesday and Wednesday's convection will have implications on the pattern for the rest of the week, so that will be something to watch closely if in heat-sensitive industries or outdoors this week.

Severe Weather Risk Tuesday Night/Wednesday Morning:

Very late Tuesday night into early Wednesday morning, an MCS is progged to develop along the nose of the nocturnal LLJ as a shortwave moves across northern Missouri. The lee cyclogenesis in Kansas will also help to sustain isentropic ascent during the overnight hours, though the primary question regarding this overnight MCS remains what the forcing mechanism will be that initiates the complex that moves into our area. Another storm complex further north into Nebraska may influence how conditions evolve throughout the day, though it does appear likely that this northern MCS will send an outflow boundary surging south into central Missouri that will be the likely initiation mechanism for storms in our area. Storms appear to initiate north and west of our area in Kansas before moving into western Missouri, with most CAMs that initiate this activity indicating that storms organize into clusters by the time they reach our area.

With the boost in the LLJ to 30-40 kts overnight, 0-3km bulk shear values increase to 50-60kts by 12Z Wednesday, which would support strong cold pool development and damaging wind gusts with this cluster of storms. Hodographs are sufficiently curved that there may be a conditional threat for QLCS tornado development as well, especially as storms progress south and east and approach the warm front spread across the area. Best severe chances remain along and northwest of the greater Lake of the Ozarks/Truman Lake corridor, which is within the Slight Risk (Level 2 of 5) area from SPC.

Severe Weather Risk Wednesday:

Scattered showers and storms may continue on and off during the day on Wednesday after the progression of the late Tuesday night system, but the 12Z model suite is increasingly pointing towards another area of severe weather potential on Wednesday evening/night across portions of southern Missouri into northern Arkansas as the shortwave aloft progresses from Kansas into Missouri. Southern portions of the state have the best instability available (1000-2000 J/kg MUCAPE) as the nocturnal LLJ ramps back up. An MCS appears to be the most likely cause of severe weather, with the primary threat being damaging winds during the evening/overnight hours as storms become more organized. However, storms may initially form as supercells or supercell-like clusters in southwest Missouri, with straight hodographs during the afternoon to early evening hours suggesting initial storms may be prone to splitting. As such, cannot fully rule out hail with strongest afternoon storms. 30-40kts of 0-3km shear could again support mesovortices embedded within the larger storm clusters, especially once the LLJ begins increasing low-level hodograph curvature. As the nocturnal LLJ ramps up, storms should become more organized into a bowing segment(s) as cold pools organize along the LLJ and shear strengthens, where the damaging wind threat is most likely to materialize.

While there is still a fair amount of uncertainty regarding the placement and overlap of key mesoscale features in the wake of the overnight convection, model consensus agrees that there is a sufficient risk for severe weather on Wednesday. As such, collaboration with SPC has resulted in bumping southern portions of the area up from a general thunderstorm risk to a Slight (Level 2 of 5) Risk with much of the other part of our area within a Marginal (Level 1 of 5) Risk for severe weather on Wednesday into Wednesday night.

Hydrology/Excessive Rainfall Concerns:

PWATs increase Tuesday to between 1.75-2", with a plume of 2-2.3" PW values advected south with the late Tuesday night/early Wednesday morning MCS/round of rainfall. Numerous CAMs indicate the potential for heavy rainfall with the convective systems (and individual storms) that occur between Tuesday night and Thursday morning, with 6 hour LPMMs of 2-3" for a given round of rainfall, which could trigger rate-driven flash flooding concerns in areas that see the strongest rainfall rates. Corfidi vectors and mean wind vectors are aligned with the theta-e gradient, which would suggest training is possible with both rounds of storms, which would also increase the threat of localized heavy rainfall and flash flooding potential.

AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/

Issued at 632 PM CDT Mon Aug 17 2026

VFR conditions and light winds will persist through the TAF period.

SGF WATCHES/WARNINGS/ADVISORIES

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