textproduct: Springfield

KEY MESSAGES

- 40-50% chance for scattered showers and thunderstorms east of Highway 65 this afternoon and evening. A few isolated 60-70 mph downburst wind gusts are possible (up to 5% chance), in addition to heavy downpours and localized flooding.

- Heat persists through early next week with moderate chances (60-70%) for multiple days of Heat Index values approaching 100-105.

- 40-50% chance for above mid-August average precipitation (0.5-0.75 inches) late next week as the jet stream sags back into the region.

SHORT TERM /THROUGH TONIGHT/

Issued at 300 AM CDT Fri Aug 7 2026

Broad longwave troughing continues to hold over the northern CONUS. A mid- and upper-level shortwave trough axis embedded within the longwave is currently position from southwest Missouri up into central Wisconsin, as noted in water vapor satellite imagery. Surface observations place the loitering stationary front across south-central Missouri and along the Kansas/Oklahoma border. RAP analysis has strong warm air advection overtop this boundary which is forcing a complex of showers and thunderstorms over east Kansas. Some of these showers may sneak into our southeast Kansas and I-49 counties this morning (15-50% chance), but for now, they appear to dissipate once entering our area.

40-50% chance for scattered showers and thunderstorms today:

Most HREF/REFS/RAP members are coming into agreement that the thunderstorm complex currently in east Kansas will develop a Mesoscale Convective Vortex (MCV) by this morning. Westerly flow aloft would slowly take this MCV eastward across south-central Missouri through the day today. Meanwhile, temperatures increasing to around 90 F, with dewpoints around 70 F will generate upwards of 2000-4000+ J/kg SBCAPE by the afternoon (speaking of which, some areas are forecast to see Heat Index values up to 100-105, particularly south of Highway 60). On a normal day like today, updrafts would need to break through any weak capping to produce storms. However, positive vorticity advection ahead of the MCV should provide some extra synoptic ascent to aid daytime heating and convergence lift to produce scattered shower and thunderstorms after 2 PM this afternoon. This would be focused east of Highway 65 where the synoptic ascent will overlap the most unstable environment. storms would then last just after sunset before nocturnal capping diminishes storms by around 10 PM or so.

Potential for isolated instances of flooding and damaging winds:

Currently, there is no SPC Severe Outlook for our area. The reasons are two-fold. One, shear will be on the weak side (10-20 kts), meaning organized severe weather is not expected. Two, models are still somewhat varied on the greatest coverage in storms. Despite the lack of shear and uncertainty in coverage, the environment in place could support a few marginally severe downbursts. The thermodynamics actually look a bit more potent than the parameters that brought yesterday's severe weather. In addition to very high instability, the RAP forecasts quite a big area of 1500-2000+ J/kg of downdraft instability (DCAPE) along with quite high Microburst parameters (9-11; Max is 12). Additionally, the Ozarks Pulse Severe Thunderstorm Index is outputting high values (16-18; Max is 20) due to 25-30 K Theta-E diffs and steep 7-8 C/km low- and mid-level lapse rates. Therefore, any thunderstorm that develops could become strong to marginally severe with downdraft wind gusts up to 60-70 mph. Added shear from the MCV could create some clusters of storms as well, which would increase this threat. The SPC included a mention of this risk in their discussion, potentially upgrading the area to a Marginal if confidence in the threat increases.

Additionally, heavy downpours and localized flooding will also be possible. Rain rates of up to 3-4 inches per hour were observed with storms yesterday, and with little change in environment today, we can expect the same sort of rates in stronger storms. Furthermore, the introduction of the MCV could result in some training of storms. For these reasons, the WPC almost introduced a Slight Risk for our area, but held off due to the dry soils and the same coverage uncertainties outlined by the SPC.

We will monitor how things evolve this morning for any potential upgrades in both SPC and WPC threat levels. For now, be aware that a few storms today could still be capable of producing damaging winds and flooding.

LONG TERM /SATURDAY THROUGH THURSDAY/

Issued at 300 AM CDT Fri Aug 7 2026

Heat persists through early next week:

The stationary front will finally be removed from our area starting Saturday. Furthermore, the mid-level trough axis will shift east of our region, producing more sinking air and rising heights/pressure. This will decrease any significant chance of rain and storms and bring persistent heat to the region through at least Tuesday/Wednesday next week. NBM 25-75th temperatures spreads continue to forecast highs in the 90s during this period, with some locations across our south and west approaching 100 F. Current dewpoint forecasts aren't expected to be overly "excessive" with values in the upper 60s to lower 70s. Therefore, Heat Index values won't be "extreme" (>110 F), and current NBM/LREF ensembles put <15% chance for >105 F. However, there are moderately-high (60-70%) chances for Heat Index values between 100-105 to occur from Saturday through at least Tuesday/Wednesday. Persistent heat like this along with little relief with lows in the lower to middle 70s will elevate heat risk as we go through next week. This may require a Heat Advisory by Monday or Tuesday.

During this period, weather is expected to be dry for most places. However, we won't exactly be under a ridge/heat dome. And with moisture being plentiful, isolated showers and thunderstorms would still be possible each day. Some medium range guidance suggests this to be the case east of Highway 65 Saturday afternoon despite chances of precipitation being <15%.

Pattern change to bring several chances of rain late next week:

As we get into the middle to latter periods of next week, global ensembles bring the jet stream a bit more south, enhancing northwesterly flow over our region. Any shortwaves that move through the flow could bring multiple chances of rain. Current forecasts place 30-60% chances across the region Wednesday and onwards. The CPC gives us a 40-50% chance for seeing above normal precipitation between August 12-16. Since normal precipitation for this time period is around 0.5-0.75 inches, there is a 40-50% chance for exceeding that amount between August 12-16.

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 615 AM CDT Fri Aug 7 2026

Radar imagery shows shower and storm cells in east Kansas, stretching into southwest Missouri. These have a 30-40% chance of coming within the vicinity of JLN around 12Z. Light to moderate rain can be expected around JLN between 12-16Z. Have included a TEMPO for this. Otherwise, elsewhere, 8-12 kt winds will shift from southerly to southwesterly by 14Z, with several layers of middle and high level clouds.

During peak heating between 21-03Z, some scattered showers and thunderstorms are expected to develop, though there's a good chance they stay east of the TAF sites. BBG has the greatest chance of seeing showers and storms nearby (50% chance). If a thunderstorm does impact a TAF site, it will be capable of producing downdraft wind gusts up to 40-60 kts.

SGF WATCHES/WARNINGS/ADVISORIES

KS...None. MO...None.