First day of fall and cooler weather

(TULSA, Okla.) Monday is the autumnal equinox, also known as the first day of fall. It is one of two days a year when the Earth’s axis is tilted neither toward nor away from the sun, resulting in a nearly equal amount of daylight and darkness at all latitudes. The chances of storms will shift to far southeast Oklahoma into Monday morning, with cooler and drier air briefly moving into northeast Oklahoma and northwest Arkansas. The stalled boundary will lift back north by Tuesday, with periodic chances of showers and thunderstorms through Thursday as the boundary remains nearby. The next upper system weakens as it lifts into the Plains by late week, with the best chances of additional precipitation likely remaining north of the area. Mid-level heights are forecast to rise going into next weekend, with more hot and humid weather in store. Monday Mostly sunny, with a high near 85. Northeast wind around 5 mph becoming east in the afternoon. Monday Night A 30 percent chance of showers and thunderstorms after 1am. Mostly cloudy, with a low around 69. East wind around 5 mph. Tuesday Showers likely and possibly a thunderstorm before 1pm, then a chance of showers and thunderstorms after 1pm. Mostly cloudy, with a high near 84. South wind 5 to 10 mph. Chance of precipitation is 60%. Tuesday Night A 30 percent chance of showers and thunderstorms, mainly after 1am. Mostly cloudy, with a low around 72. South wind 5 to 10 mph. Wednesday A 40 percent chance of showers and thunderstorms, mainly after 1pm. Mostly cloudy, with a high near 88. Southwest wind around 10 mph. Wednesday Night A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 68. Southwest wind around 5 mph becoming southeast after midnight. Thursday A 20 percent chance of showers and thunderstorms. Partly sunny, with a high near 85. South wind 5 to 10 mph. Thursday Night A 20 percent chance of showers and thunderstorms. Partly cloudy, with a low around 71. South wind 10 to 15 mph, with gusts as high as 20 mph. Friday A 20 percent chance of showers and thunderstorms. Partly sunny, with a high near 85. South wind around 15 mph, with gusts as high as 25 mph. Friday Night A 20 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 72. South wind 10 to 15 mph. Saturday Partly sunny, with a high near 87. South wind 10 to 15 mph.