Latest National Weather Service and model guidance for Dallas on May 18 show a warm, moist air mass with southerly flow and scattered afternoon convection that could cap the daily maximum between the upper 80s and low 90s. Small differences in cloud timing, thunderstorm initiation, and boundary-layer mixing explain why traders assign nearly equal weight to the 88–89 °F, 86–87 °F, and 90–91 °F bins; earlier or stronger storms would trim the peak while clearer skies or delayed convection would push it higher. Historical May climatology supports highs near 85 °F as a baseline, yet current guidance runs 2–5 °F above average, leaving the exact outcome sensitive to the next model update and afternoon observations.