textproduct: Springfield

KEY MESSAGES

- A Moderate Risk (3 out of 4) for repeated rounds of thunderstorms and heavy rainfall that may result in flash flooding this morning into the afternoon. Increasing confidence in a thunderstorm complex stalling into west central and central MO. A Flood Watch in effect for an area north of Interstate 44 towards the Highway 54 corridor.

- A Slight Risk (2 out of 5) for a few strong to severe thunderstorms this morning into the afternoon. Primary hazard is damaging wind gusts.

- A Slight Risk (2 out of 5) for severe thunderstorms overnight tonight into Tuesday. A line of thunderstorms expected to quickly move through the area, with the primary hazard being damaging wind gusts.

- Additional rainfall chances (30-50%) mid to late week along with cooler temperatures.

SHORT TERM /THROUGH TONIGHT/

Issued at 300 AM CDT Mon May 18 2026

This Morning-This Afternoon: A thunderstorm complex is gradually sliding southeast this morning across portions of eastern KS and northwest MO. This complex has become outflow dominant in nature, with any severe potential limited to damaging wind gusts at this point. This complex is expected to continue to sink southeast into portions of west central and central MO by early this morning/near sunrise. The environment becomes less favorable for organized thunderstorms given the lack of sufficient wind shear into this area. However, there may be just enough (20 to 30 knots deep- layer) in the vicinity of MUCAPE (1500 to 2000 J/kg) to support a few strong to severe thunderstorm segments. Much of the activity becomes elevated in nature this morning. The primary risk would be damaging wind gusts up to 60 mph. SPC has a Marginal (1 of 5) to Slight (2 of 5) to capture this severe potential. Expectations are for this complex to stall by mid- morning in the general area north of Interstate 44 towards the Highway 54 corridor. This will be key to a rapidly increasing concern for heavy rainfall and flash flooding that will be discussed in more detail below. An additional severe potential occurs late this morning into the afternoon with redevelopment as a low- level jet persists over the area. CAMs depict scattered thunderstorms rapidly developing across southern MO and lifting towards the stalling complex. Confidence in this scattered development is low to medium given the strong CIN to the south. Nonetheless, any activity that does develop will pose the potential hazards may include hail to the size of quarters and damaging wind gusts up to 60 mph. It is plausible some locations remain dry through this morning and afternoon across far southern MO, with PoPs 60-90% along and north of Interstate 44, falling off to 10-30% along the MO/AR border. Overall, there is still some subtle uncertainties remaining on how the mesoscale unfolds this morning and afternoon, and the true extent of the associated severe potential.

As for the heavy rainfall and flash flooding potential, the attention is focused on the complex stalling into west central and central MO this morning. This environment is increasingly favorable for heavy rainfall to occur, with the complex slowing into this area thanks to very weak steering flow as seen with Corfidi vectors becoming west to east oriented at 5 knots or less. As moisture (PWATs 1.5 to 1.8 inches) continues to advect into the area, efficient rainfall rates are likely as repeated showers and thunderstorms occur over the same areas this morning into the afternoon. Guidance has trended into widespread agreement on this heavy rainfall, further increasing our confidence in heavy rainfall that will likely result in some areas of flash flooding today. The latest HREF Localized Probability Matched-Mean (LPMM) depicts a widespread corridor of 1 to 3 inches along Highway 54, with localized amounts approaching 4 to 6 inches. Given this trend and increasing confidence, a Flood Watch has been issued for portions of west central and central MO. This watch begins at 7 am this morning and runs through this evening. Further expansion in time and space may be warranted if needed. WPC has captured this heavy rainfall/flash flooding potential with an upgrade to a Moderate Excessive Rainfall Outlook (3 out of 4). There is some lingering uncertainty on how long this activity festers across the area into the afternoon/early evening, that will be best captured with trends through this morning.

Tonight-Tuesday Morning: As we progress into tonight, the low-level jet will strengthen again as lift increases. Widespread severe thunderstorms are expected to develop across central/eastern KS and quickly grow upscale into a line of thunderstorms. Ensembles continue to depict the strongest lift and wind shear are focused north and west of the area where Enhanced to Moderate Severe Outlooks are present. Further to the southeast into our area, a Slight Risk (2 out of 5) is draped through the area. The most likely scenario is for the line of thunderstorms to gradually weaken as it pushes into southeast KS and west central MO overnight tonight. However, we do not want to downplay the uncertainty in the mesoscale, as just a bit more shear and instability may further fuel strong to severe thunderstorms in our area overnight into Tuesday morning. Primary hazard is damaging wind gusts up to 60 mph. Additional hazards may include large hail up to the size of quarters and a brief tornado, though these are more focused across the north and western portions of the area as line enters the area overnight. The current speed of the front and associated line moving through the area are expected to be quick, with the front potentially clearing the area by mid Tuesday morning. If this quick moving scenario plays out, any severe potential on Tuesday afternoon would be nullified. Additionally, a progressive front would limit the potential for heavy rainfall and flash flooding.

Overall, it is expected to be an active next 24 to 36 hours, with some lingering uncertainties in the mesoscale. Confidence has increased in the heavy rainfall and flash flooding this morning into the afternoon, in additional to a few scattered strong to severe thunderstorms. Highs today reach into the lower to middle 80s, with dewpoints making it feel quite muggy in the upper 60s to near 70. Gusty southerly winds around 25 to 35 mph persist through today and tonight. By late tonight into early Tuesday morning, attention turns towards the quick moving line of thunderstorms with an additional severe potential. Continue to follow the forecast for updates.

LONG TERM /TUESDAY THROUGH SUNDAY/

Issued at 300 AM CDT Mon May 18 2026

Remainder of Tuesday: Behind the frontal passage, winds will turn out of northwest as cooler air gradually funnels into the region. Lows Tuesday night fall into the 50s to near 60.

Wednesday-Thursday: Ensemble guidance suggests low rain chances (20-50%) lingering post- frontal into Wednesday, particularly across southern MO. Meanwhile, cooler temperatures prevail on Wednesday with highs topping out in the upper 60s.

This pattern persists into Thursday, with additional rain chances (20-50%) into Thursday afternoon and night. Temperatures will gradually be on the rebound with subtle mid- level height rises.

Next Weekend: The general pattern remains southwesterly flow, with additional shortwaves tracking through the region into next weekend. There is uncertainty on the exact timing and strength of these waves,that will be better resolved over the coming days. Nonetheless, carrying additional rain chances into next weekend. A warming trend returns into next weekend as well.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Issued at 600 AM CDT Mon May 18 2026

A thunderstorm complex is stalling out to north of the TAF sites this morning, with isolated showers developing across southern MO if the vicinity of a strong low-level jet. PROB30 group for isolated showers through this morning, before introducing thunderstorm chances late morning into the afternoon. Instances of MVFR to IFR flight conditions within any thunderstorms as a result of reduced visibilities and ceilings. TAF sites should become shower/storm free by late afternoon and evening, before a line of thunderstorms approaches towards 12Z on Tuesday morning. Mid to high level clouds persist through the period. Gusty south winds through today, with gusts around 20 to 30 knots. LLWS introduced overnight tonight around 40 to 50 knots.

CLIMATE

Issued at 200 PM CDT Sun May 17 2026

Record High Temperatures:

May 18: KSGF: 88/1962 KJLN: 90/1987 KVIH: 88/1996 KUNO: 89/2001

Record Warmest Low Temperatures:

May 18: KSGF: 68/1996 KJLN: 74/1996 KUNO: 66/2017 KVIH: 70/1996

May 19: KSGF: 69/2013 KJLN: 74/1996 KUNO: 70/1996 KVIH: 70/1996

SGF WATCHES/WARNINGS/ADVISORIES

KS...None. MO...Flood Watch through this evening for MOZ055>058-066>071- 078>081.