Good Friday Morning. Patchy light fog out there this morning. I didn’t notice anything too thick. Overnight rain and storms have pushed South of the area and for the first time since Saturday Afternoon I can say our area is 100% void of rainfall. But wait! In comes the next MCS (Mesoscale Convective System) already approaching the mountains this morning.
What in the world is that you ask? A MCS is an area of thunderstorms that have produced their own cool pool of air behind them and then that cool pool of air drives a line of storms along its outflow boundary. These things can have many different movements and can develop into Boeing segments that produce a swath of damaging straight line winds. Those bowing segments can grow and become long lived as what we call a derecho. These MCS’s are popular as we get into June and July and are usually sparked by a weak piece of energy in the atmosphere or by regional areas of differential heating. These start as one or two storms and quickly grow and spread kind of like some rashes do on the body.
Overnight a MCS approached the mountains but broke up as they moved East because all of our atmospheric energy was used up earlier yesterday afternoon. Our atmosphere never recovered from the first round, so the storms that came in around 8pm started decaying as they came over the mountains. That’s not before love swaths of tree damage we’re reported in Madison County as those early night storms pushed through there. Two storms managed to survive and only one remained severe as it moved out of Buncombe into Rutherford County. The other storm developed quickly in Northern Caldwell’s Yadkin River Valley but it quickly died as well.
This morning’s MCS is moving East through the Tennessee Valley and the Cumberland Plateau. At 7:00 publish time these storms were approaching Knoxville TN. Models have this line of storms weakening as they approach they mountains by mid morning. That outflow should continue East though and it looks like it will be a focal point for scattered showers and storms across the foothills and piedmont around Noon.
Once the storms redevelop around Noo. They will move East at around 15-20mph, which is much more progressive than we have seen in the last few days. This should limit the flash flood threat today to only localized areas. For that reason the flash flood watch was allowed to expire at 2:00am this morning. Highs today should top out in the mid 80’s.
Going into the weekend rain chances drop to around 20-30% but temps warm into the mid and upper 80’s. A few areas will tickle 90° as well, especially on Saturday.
The extended outlook keeps the Southeast looking very active through mid June. Stay tuned.
Model projected rainfall through midnight tonight.