

Left panel indicates a greater than 30 percent probability of damaging winds within 25 miles of a point and, in the hatched area, winds of over 75 mph. Right panel shows culprit upper level disturbance that may serve as a trigger for storms. (NOAA and StormVistaWxMiodels.com)

NOAA’s Storm Prediction Center indicates the threat of damaging winds in the D.C. metro region. In its technical discussion, SPC writes: “POTENTIAL WILL EXIST FOR THE EVOLUTION OF ANOTHER BOW ECHO SYSTEM CAPABLE OF POTENTIALLY WIDESPREAD DAMAGING WINDS.”

Notice the hatched area in the graphic above (left panel) indicating the potential for “significant” severe weather - in this case winds of over 75 mph.

The cause is a disturbance in the atmosphere zipping by just to our north this afternoon and evening (see right panel in image above). It’s passage coincides exactly with maximum daytime heating when the atmosphere will be juiced and primed for explosive thunderstorm development. Winds aloft of 60-70 mph or higher may crash to the ground in violent thunderstorm downdrafts. There’s a chance the worst of the storms pass to the south - although I said that last night, and look what what happened.

At this point, the most likely timing for storms seems to be between 5 and 10 p.m. We will keep you posted on any watches or warnings issued, as well the evolution of the storm complex, assuming it develops.

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