A large zone of high pressure extending from the ocean surface to 20,000 feet in the atmosphere remains steady over the western Atlantic. This is serving to pump hot and humid weather over the Eastern Seaboard with mainly clear skies. Early this morning temperatures have only fallen into the middle 70s. We expect temperatures only to fall another few degrees overnight. Ample sunshine and a warm start will allow temperatures to peak in the mid 90s this afternoon. Later this afternoon a disturbance in the jet stream that has led to several days of showers and storms from the central Gulf Coast to the Ohio Valley will approach the region and bring scattered to isolated storms to the region. Initially we expect storms to form over the mountains of western Maryland in the late morning and then slide east and reach the metro area late this afternoon. A few of the storms will linger in the early evening before dissipating as the heat of the day departs.
For tomorrow, the chances for more widespread thunderstorms increases as the heart of the jet stream disturbance passes overhead while the lower atmosphere is energized by the very warm, humid air mass. A couple of the storms may be strong. Somewhat drier air will briefly try to return on Tuesday, but it will still be sufficiently warm and humid at the ground and cool enough aloft to spark a few stray thunderstorms.