What you do today often impacts what tomorrow brings. For example, if tonight you picked up Chinese food and brought it home….but got a DOUBLE order this time, you’ll likely have more than enough for a nice dinner tomorrow night, too. Just the same, if you have a big presentation to give tomorrow, but spend no time getting it together tonight, chances are it won’t go as well as you hoped when it’s “show time”.
Similarly, our weather tonight will very likely impact what happens in our area for thunderstorms tomorrow. It doesn’t always work this way, but in our current weather set-up, it will.
Right now, showers and thunderstorms are building in from the north. These have steadily pushed southward today and this evening.
However, there’s no guarantee they’ll pass through ALL of Middle Tennessee before fizzling.
The computer model below indicates they’ll make it all the way through the TN/AL line (for those curious…it’s the 9z RPM run).
However, a more current run of the same computer model shows the rain halting much farther north…
That’s important because these storms are producing and will leave behind an outflow boundary. An outflow boundary is essentially a boundary that marks where there’s a shift in wind direction. You can see it very clearly now on a view of the National Weather Service radar in Nashville (below). See that bluish-green faint line?
Winds ahead of it are blowing from the southwest. Winds behind it are blowing from Kentucky toward Tennessee.
Tomorrow, as the sun comes up and goes to work, this outflow boundary (which will just be hanging out where the storms leave it overnight, just before they fizzle) will be the focal point for NEW storms to form. If the outflow boundary is left in Middle Tennessee, our first storms of the afternoon will likely ignite along it. If it pushes all the way through Tennessee, into Alabama and Georgia, early afternoon storms will fire there first.
For our latest on our thinking on where storms will halt their southward progression tonight….and where new ones will first fire tomorrow….plus an update on tomorrow’s severe storm threat, be sure to watch Lisa Spencer on Channel 4 News at 10pm.