Before the Storms: Cloudy & Humid
We remain in this pattern of cloudy, unseasonably humid weather. With all this humidity, weather models were picking up on north-moving showers today, but none of that really materialized.
Patchy fog (fog in spots) is expected again overnight and into the early morning hours. Habitually foggy spots may even develop some dense fog.
Thursday will look a lot like today, as we await the arrival of our first real “secondary severe season” set of storms. We may see a little lonely shower or two wander across the area Thursday.
Friday Rain & Storms
An upper level trough (low pressure in the upper reaches of the atmosphere) and a corresponding surface cold front is on its way to Middle Tennessee.
Ahead of that will be a line of rain and thunderstorms.
Let’s the use the NAM4 model’s guess at the timing of all this:
Early Friday morning — which will be before the storms arrive — there will be lots of wind shear in place, most of that in the lowest layer of the atmosphere, nearest to the surface.
At the same time, there will be very little energy for the storms to tap in to . . . but with all this shear in place, anything it can tap into can get strong/severe quickly. Current thinking is that the strongest storms will occur in NW Middle Tennessee — but not for us.
The reason we think “not for us”: by the time the storms work across I-65, the surface winds should shift to the west, substantially weakening the amount of wind shear the storms will enjoy to our northwest. With diminished wind shear and already-low amounts of tap-able storm energy, we do not expect this to be any more than a rain and minor wind event for us.
All this assumes the timing on this stays the same. There is potential for error, and we could be wrong and the storms end up being worse than this. So, please stay alert to multiple reliable sources for your weather info. Of particular interest will be the Storm Prediction Center’s “Day 2” outlook, which will be up in the morning. Again, stay tuned.
Despite a “meh” severe outlook, it’s still going to rain.
The GFS model expects 0.40″ of rain to fall in three hours as the line strafes both counties:
This total seems to be agreeable to the other weather models. Still, the models are probably a bit too dramatic about the total rain — NWS forecasts about 0.35″ for the entire rain event Friday.
Saturday outdoorsy sports leagues beware, especially if this line is delayed — that’ll give it more stormy and rainy potential.
The cold front is expected to stall after it passes late Friday, which means it will take a little bit of time for the drier and colder air to filter in.
Still, a pretty nice weekend.
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Categories: Forecast Blogs