Forecast models from the National Weather Service and private ensembles project a warm, moist air mass over north Texas on May 18, with surface highs likely peaking in the upper 80s to low 90s Fahrenheit amid moderate southerly flow and strong diurnal heating. Slight differences in the timing and coverage of afternoon convection create the narrow spread among the top market outcomes, as early thunderstorm development could cap temperatures near 88–89 °F while delayed or scattered storms would allow readings to reach 92 °F or higher. Historical May climatology for Dallas shows an average daily maximum near 86 °F, providing context for the current elevated guidance. Updated model runs and National Weather Service afternoon updates on May 17 will clarify the convective trigger and steering patterns that ultimately determine the day’s peak reading.