Tropical Trouble Could Spread Tropical Rains Into The Foothills Late Week

High pressure to our West is currently in control of our weather across Western North Carolina. Over the next couple of days a series of weak disturbances will traverse the area, bringing with them the chances for scattered showers and thunderstorms each day. By late week a cold front will move into the area and stall. Meanwhile a system will most likely develop in the Gulf Of Mexico and track into the southeastern United States late week into next weekend. The timing and placement of the heaviest rains and winds have yet to be determined. Chances of significant flash flooding rains are increasing across the western Carolina’s though. Now is a great time to clean gutters, storm drains, and trim trees away from your home.

Sunday Night into Monday:
Tonight, we can expect some isolated showers, especially along and north of I-40. Low clouds will move in from the northeast toward daybreak, limiting fog formation. Temperatures will be mild, with lows in the mid 60’s, rather warm for this time of year.

Monday into Tuesday:
We’ll see scattered showers mainly in the afternoon Tuesday with only isolated chances Monday. Though the severe storm risk is higher in Tennessee, we could still see a few storms with damaging wind gusts due to high instability and wind shear. Temperatures top out around 80° along I-40 and the mid 80’s along Highway 74. Areas along I-85 may reach the upper 80’s.

Tuesday into Wednesday:
A strong ridge of high pressure will shift east, exposing our area to increasing moisture from the approaching front and tropical moisture surging north ahead of the front. Expect highs in the low to mid-80s with scattered showers and a chance of thunderstorms, particularly in the afternoon.

By Wednesday, an upper-level low-pressure system will settle over the Ozarks, bringing widespread moisture and another round of scattered showers and thunderstorms. Highs will be similar to Tuesday, cooling slightly.

(Weather Nerd Intermission)

The positioning of the upper-level low-pressure system will play a crucial role in determining the strength and trajectory of the developing tropical system in the Gulf of Mexico. As noted by meteorologist Jim Cantore, this upper-level low, along with its associated trough, will enhance the northward acceleration of the tropical system.

From a physics standpoint, the placement of the upper-level low over the Ozarks is particularly significant because it creates a favorable environment for enhanced atmospheric ventilation over the Gulf. This enhanced ventilation results from increased divergence aloft, which effectively lowers the atmospheric pressure at higher altitudes above the tropical system. The resulting pressure gradient between the upper atmosphere and the surface promotes the rapid evacuation of air away from the storm’s center, allowing for more efficient rising motion of warm, moist air within the system.

This dynamic interaction amplifies the storm’s convective processes, thereby supporting rapid intensification. The increased pressure difference aloft reduces resistance to the storm’s outflow, allowing it to strengthen more quickly. In essence, this upper-level configuration acts as a catalyst, enhancing the storm’s growth potential by optimizing the thermodynamic and dynamic conditions required for intensification. Kudos to Jim for catching this!

Onward!!!

Wednesday Night through the Weekend:
The developing tropical low is expected to form over the Gulf of Mexico by midweek. By Thursday and Friday, this system will move northward, but the exact impact on the Western Carolinas will depend on the strength and position of surrounding weather systems (detailed above). If the low tracks more eastward, we could see significant moisture in our area; a more westward track would mean less rain for us but could put our region in the dirty sector of the storm, meaning an increased risk of severe thunderstorms and tornadoes.

Regardless of the exact path, it’s likely that we’ll see some rain Thursday, Friday, and Saturday, but the amount remains uncertain. The rest of the weekend forecast will heavily depend on how the tropical system evolves, so stay tuned for updates as the week progresses. This upper level low could move in behind the tropical low and continue our southeasterly fetch off of the Atlantic. This would prolong the any flood risk into early next week.