We’re headed into the Smokey Mountains and the eastern tip of Tennessee.
At 555PM, ET, Johnson City was reporting clear skies with a temperature of 68 degrees. Weak pressure gradient across the east belied the massive system developing over the High Plains, triggering the first real severe storm outbreak of the season. A warm front is extending into Tennessee is associated with this boundary, but is not developing much by way of precipitation. Even so, the presence of the boundary in Tennessee lends to power of the system in the Plains.
The cause of the system is a cut off upper level low over the western US. The subtropical jet over Mexico will lift north to intercept the low and transport it towards the Tennessee Valley. When the low pushes west it will tap into the Gulf and it’s moisture. The resulting rain and thunderstorms, which will arrive in Johnson City late Friday into Saturday will bring about torrential rains, with 1-2 inches of rain possible to begin the weekend.
Tomorrow – Late rain, High 74, High 51
Saturday – Torrential rain expected in the evening, with thunderstorms possible, High 75, Low 56
TWC: Tomorrow – Showers early then scattered thunderstorms developing later in the day. High 74, Low 50
Saturday – Thundershowers. High 75, Low 55
AW: Tomorrow – Variable cloudiness with a shower High 71, Low 47
Saturday – Mostly cloudy with a shower or thunderstorm around High 74, Low 53
NWS: Tomorrow – A 40 percent chance of showers and thunderstorms. Mostly cloudy High 74, Low 48
Saturday – Showers and thunderstorms likely, mainly after 2pm. Mostly cloudy High 74, Low 55
WB: Tomorrow – Mostly cloudy with scattered showers and thunderstorms High 74, Low 48
Saturday – Cloudy. Scattered showers and thunderstorms in the morning…then showers and thunderstorms likely in the afternoon. Some storms may be severe in the afternoon. Locally heavy rainfall possible in the afternoon. High 75, Low 55