Severe weather event for Monday morning coming into focus

/ April 12, 2020 at 6:09 PM

Unfortunately, we’ll be needing to spend this Easter evening getting ready for a round of strong storms tomorrow morning. The severe weather threat for Monday is coming into focus, and there’s not been much change to the previous thinking: A line of strong to severe thunderstorms will push through the area during the morning hours. These thunderstorms will be moving into an atmosphere that is favorable for strong, damaging wind gusts (70 MPH possible, according to the National Weather Service), a few tornadoes (one or two of which could be fairly potent), and large hail.

Still some timing kinks to work out

Source: National Weather Service, Charleston, SC

According to its latest briefing package, the National Weather Service says the timeframe for severe weather is between 6am and noon across the county warning area, with an eye on impacts reaching the western edges of the Tri-County area between 9 and 11am, and then impacts in the Charleston metro area between 10am and noon.

This could yet be sped up, though, depending on what transpires to the west. There are, in fact, signs in some of the High-Resolution Rapid Refresh data that the line of storms could come through the metro area an hour or two ahead of this forecast, so be flexible and plan using the 6am-noon estimate until the finer details become clearer.

Ways this could be a little weaker

There are a couple other potential flies in the ointment as well. First, this forecast assumes rich moisture return ahead of it. If there is any disruption to the quality of that moisture return, it could disrupt the severe threat. This does not appear to be a likely scenario, though, as the orientation of the line and the location of the forcing mechanisms should keep areas to our south relatively clear.

The other thing to watch will be water temperatures around 70°. While perhaps not as disruptive to an advancing line of storms as water temperatures in the 50s, we cannot rule out some interference from the marine layer on helping to weaken this line. However, this may also end up being a moot point with such potent winds aloft and plentiful wind shear to keep thunderstorms rolling. Southwesterly trajectories also pose a problem for this kind of scenario as well.

Let’s hope we can get some weakening, but plan for that not to happen.

What to do tonight

What to do tomorrow

With any luck, we should be done with these storms by early afternoon. The sun will indeed come back out, and temperatures will head into the low 80s as the cold front won’t quite have gotten through just yet.

I’ll be providing updates as needed throughout the event starting early tomorrow morning. I hope you’ll ride along.

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