In America's Heartland, autumn usually provides a gradual shift from summer heat to winter's chill, offering plenty of sunny, dry weather along the way. But today, those contrasting seasons have been brought together and a clash zone, characterized by thunderstorms and heavy rain, stretches from central Texas to the Ohio Valley.
A broad dip in the jet stream, known as a trough, has produced winter-like conditions across the Intermountain West and Northern Plains while summer heat and humidity have developed across the Southeast. Meanwhile, low pressure, with its counterclockwise winds, sits over New Mexico and high pressure, with its clockwise winds, is camped over the Mid Atlantic region; this combination is pumping warm, humid air up from the Gulf of Mexico and across the Southern Plains and Lower Mississippi Valley. Near the edge of the cold front, this soupy air is lifted, producing the heavy rain and thunderstorms; up to 8 inches of rain is expected in some areas of eastern Oklahoma, southern Missouri and southern Illinois.
Our image of the seasons is based on our observation of weather patterns over many years. We generally picture October as a month of sunny days, colorful foliage and crisp, clear nights. But nature does not always comply with our expectations and this day will look and feel more like April.
