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Monday’s severe threat: Timing is everything

/ April 11, 2020 at 6:19 PM

What’s clear about Monday is that, at some point, there will be a squall line with strong thunderstorms coming through the area. These storms will be capable of producing wind damage and could spawn a tornado or two along the leading edge of the line.

The degree to which this threat will materialize is going to be highly dependent on timing, and that’s where it gets tricky — but I’ll do my best to demystify it.

Sunday’s forecast

We should get a fair bit of Easter Sunday in high and dry across the area. Expect showers and thunderstorms to begin to develop and approach the Tri-County area in the afternoon and evening hours as a warm front lifts north across the area. Much of this activity should stay below severe limits, but it is worth noting that a few strong wind gusts will be possible as the wind fields strengthen. In fact, I would plan for gusty winds even outside of thunderstorms. Take some time tonight to bring in loose items — you and your neighbors will be happy with fewer projectiles.

We’ll be watching the weather to our west closely as a fairly significant severe weather outbreak is probable in much of Louisiana, Mississippi, and Alabama. This activity will congeal into a squall line that will be driven eastward to affect our weather on…

Monday

The greatest risk of severe weather in the Tri-County area arrives ahead of a squall line on Monday. Here is where timing gets very tricky. Much of the model suite has slowed down over the past day or so, bringing the line of thunderstorms into the area during the early afternoon hours. This wouldn’t be awesome, as it would give the atmosphere time to become more unstable as daytime heating went on.

The squall line is going to have plenty of wind energy to work with as is, with a strong low-level jet in place. If it can tap into even more thermodynamic instability, it will have an easier time bringing more of that damaging wind to the surface. Additionally, the tornado threat could kick up a couple notches as well if this can be realized.

However, it is worth noting that there are many instances where squall lines outpace model projections of their timing. If this is the case — and I suspect it may be — the line of thunderstorms could come through earlier in the day. And if that happens, the risk for severe weather may not be as widespread. Yes, there will probably still be some downed trees and power lines, and a tornado still won’t be off the table, but the scale of the event perhaps becomes a lot smaller.

Dealing with severe weather during a pandemic

The bottom line is simply this: There could be strong to severe storms on Monday that may knock out power and cause property damage. Not everyone is going to see severe weather, but you want to be ready for it in case you do. This is a good opportunity to keep in mind what you would do if a severe thunderstorm — especially a tornado — approaches your area:

This whole thing is complicated by the ongoing COVID-19 pandemic. For example, people living in mobile homes will almost certainly need a place to go for site-built shelter in a severe storm, and that location may likely be communal. South Carolina’s Emergency Management Division advises the following:

So, take the rest of today and the first part of Sunday to make sure you have reliable ways to receive weather warnings — NOAA Weather Radio, smartphone apps such as StormWatch+, broadcast media — and a safe place to go if a weather warning is issued. With those two items in your toolbox, you’re going to be just fine.

Keep an eye on forecasts tomorrow — I’ll have my next full update tomorrow afternoon. With another couple model cycles completed and the event ongoing, we should learn more of the finer details about what impacts to expect here on Monday. Stay tuned.


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