Area Forecast Discussion

KEY MESSAGES

- 60-90% morning rain chances turns into scattered thunderstorms this afternoon (30-60% chance). More widespread rain chances will occur Sunday into Monday (90% chance). No severe weather expected at this time.

- 1-3 inch per hour downpours possible with any stronger thunderstorm this weekend. Therefore, there is a Slight (2 of 4) Risk for excessive rainfall and localized flash flooding Sunday through Monday. A Flood Watch may be needed if confidence increases.

- Above normal temperatures and humidity next week will lead to Heat Index values in the mid-90s to lower 100s. First heat of the season and warm nighttime temperatures may heighten heat- related impacts.

SHORT TERM /THROUGH TONIGHT/

Issued at 300 AM CDT Sat Jun 6 2026

Current water vapor imagery depicts a mid- and upper-level closed low churning over the Red River Valley as a separate shortwave traversing the Great Lakes led to a decaying complex of thunderstorms over northern Missouri. Between the two features, westerly flow overtop southerly surface flow is evident across our area. The southerly flow is keeping moisture plentiful, keeping nighttime lows mild in the middle 60s to lower 70s.

60-90% morning rain chances this morning through mid-day:

A narrow ribbon of dry air can be seen east of the closed low in TX/OK, marking the area of greatest positive vorticity advection (PVA). This feature is progged to lift north into our region early this morning. With PVA being the main source of lift and greater MUCAPE values being advected north of the region, rain is expected to be widespread but light to moderate through the morning (60-90% chance south of I-44). Still, the HREF mean keeps 500-1000 J/kg MUCAPE, so embedded thunderstorms are still possible during the morning hours.

30-60% chance of scattered thunderstorms this afternoon:

As daytime mixing progresses, widespread light rain will dissipate, transitioning to scattered thunderstorms across the area as daytime heating increases instability ahead of the churning closed low and associated synoptic ascent. Coverage of these storms is a bit uncertain due to lack of run-to-run consistency in CAMs and upper 70s temperatures limiting instability. However, global models depict subtle large-scale ascent within a moist and rather uncapped environment, which leads one to believe that numerous small-in-area showers and storms are possible across our CWA (30-60% chance).

Our 00Z balloon sounding depicted deep moisture through the atmosphere with a PWAT value of 1.55 in. This is already >90th percentile of PWATs for this time of year according to the SPC sounding climatology. With the origin of the closed low being over the eastern Pacific, and meridional flow ahead of the system pulling in deep Gulf moisture, PWATs are forecast to rise to 1.8-2.0 inches, which is around maximum for this time of year. This paired with tall, skinny CAPE profiles and slow- moving storms will lead to 1-3 inch per hour rain rates within any stronger thunderstorms. This may lead to a very isolated and localized flash flooding threat today and tonight.

LONG TERM /SUNDAY THROUGH FRIDAY/

Issued at 300 AM CDT Sat Jun 6 2026

Slight Risk for excessive rainfall Sunday through Monday:

The environment will remain the same through Sunday and into Monday as the closed low slowly churns lifts north-northeast. As the closed low becomes more absorbed in the background flow over the western CONUS, it will take on more of a shortwave shape with a sharper trough shape over western Missouri and into the ArkLaTex region. The sharper shape will increase PVA and synoptic ascent across the area for Sunday into Sunday night. A stronger low-level jet will also develop as a response, nosing into the area with increased warm air and moisture advection. This sets the stage for greater coverage of showers and thunderstorms Sunday and Sunday night (80-90% chance).

Since the environment remains the same, 1-3 in/hr rates are still possible with any thunderstorm. However, with greater lift introduced to the area, coverage of thunderstorms is expected to be greater. This will increase the chance for repeated rounds of heavy rainfall, leading to a Slight (2 of 4) Risk for excessive rainfall and flash flooding Sunday through Sunday night. This risk continues on into Monday, east of Highway 65, as the shortwave axis continues eastward.

Since storms are expected to be scattered, placement of the greatest rainfall and subsequent risk for flash flooding is highly uncertain and will depend on where specific locations see multiple thunderstorms. Once confidence increases on where the greatest forcing and coverage of storms becomes clear (and where they may line up with previous rainfall), a Flood Watch may be issued.

Additionally, we will need to monitor how the shortwave evolves and phases with the background flow. If winds aloft increase, there may become enough shear for an isolated/marginal severe threat Sunday and Monday.

Persistent heat enters the region for much of next week:

Once the wave exits the region, global ensembles show a shortwave ridge axis setting up over the Ozarks as an energetic trough enters the northwestern CONUS. ESATs depict this ridge to possess >97.5th percentile mid-level geopotential heights for this time of year. This will bring warm temperatures in the lower 90s for Tuesday through Friday. Furthermore, the low- level moisture in place is progged to be >99.5th percentile. These above normal temperatures and humidity will lead to Heat Index values ranging from the middle 90s to the lower 100s (reaching near 110 F in some spots).

While this is not uncommon heat for the Ozarks to experience, it is rather atypical for early June as contextualized by our "normal" max heat index of around 97 F for early June as outlined by the CPC. The CPC gives an 80-90% chance of exceeding this above normal heat index threshold at any point next week. With this being the first heat of the season, NBM spreads forecasting it to be over multiple days, and with warm nighttime temperatures in the 70s providing little relief, heat impacts may be slightly heightened from normal 100-110 F heat index impacts. This is reflected with a widespread Major Risk for heat-related impacts, especially Wednesday and Thursday. This means the heat will likely affect those without cooling or hydration. Extra care for heat-related impacts should be exercised come next week.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1243 PM CDT Sat Jun 6 2026

Ceilings will oscillate between VFR/MVFR through the period as heavy rain moves through the area. There will be brief periods of dry time, then heavy rain will start again. No severe weather is expected, but there may be a few rumbles of thunder in this activity. Visibilities may drop to 1 to 2 SM within the heaviest bands of rain. Winds will stay southerly and gust up to 15 mph through the period.

SGF WATCHES / WARNINGS / ADVISORIES

KS...Flood Watch from Sunday afternoon through Monday afternoon for KSZ073-097-101. MO...Flood Watch from Sunday afternoon through Monday afternoon for MOZ055-066>069-077>081-088>096-101>105.