Monday 10 a.m.
"The scene soon fearfully changed, with a most singular change in the appearance of the clouds, which varied in color from black to green and then to straw colored... The city in a twinkling was completely enveloped in dust, houses unroofed and demolished, trees uprooted, and utmost confusion prevailed in the almost cimmerian darkness that encompassed the city. The wind shifted from southwest to northwest, and amid the clashing of the elements, amid the lightning and loud peals pof thunder, the rain poured down in torrents - a miniature deluge, intermixed with a heavy storm of hail."
"I learned from the conductor of the freight train, that its force was maintained from Cincinnati outwards to a point some 15 miles east of Athens, after which it seemed to lose its power."
These were accounts from newspapers reporting on the "Ohio Valley Wind Rush" of May 21, 1860! This was in many ways similar to the derecho that ripped through area from West Virginia, Virginia and Maryland Friday night.
Looking ahead, a series of systems will raise shower/thunderstorm likelihoods as they move through the Great Lakes and Northeast. This morning's NAM forecast really blows up a system that will reach Pennsylvania tomorrow night, dumping more than 2 inches of rain on Boston during the day Wednesday. Judging from how models have been handling things during the last week, this is not the last word on what will happen on July 4th. Here's today's video.
The Fourth of July will be hot across much of the Northeast and in the Great Lakes. Where and when thunderstorms will hit are still open to question.
More than 110,000 lightning strikes occurred in the northeast third of the nation in the 24 hours ending at 11 a.m. EDT today (June 13).
This map shows the low pressure at the western edge. The isobars help define the location of the frontal boundary between the hot and cool air masses.
This map shows the area that could have damaging thunderstorms tomorrow and tomorrow night.
The Northeast regional radar at 10 AM showed a large area affected by showers and thunderstorms:
Whereas Andrea was centered in eastern South Carolina at 8 a.m., this satellite water vapor image shows the greatest concentration of moisture is well northeast of the surface circulation center
Quite a few models are in use, and this map shows there is widespread agreement on where the center of this storm is going.