Fall 2025 WX Discussion Thread

[John1122]

Heavy rain starting here now, looks juiced upstream. Had around 1.3 inches overnight last night.

[Carvers Gap]

On 9/22/2025 at 10:40 PM, midwoodian said:

Have a big outdoor event up here on Signal Mountain tomorrow evening. Looks like possibility of a shower rolling through around 7 pm. Low overall %.

How likely is it something develops tomorrow between 5 and 8 pm, and if it does, will it move through quickly?


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How did things turn out?

[John1122]

Added 1.1 inches of additional rain from midnight through early morning. 

[dwagner88]

Pretty sparse rainfall down here so far. I got 0.46" Sunday morning, but very little since then.

[midwoodian]

How did things turn out?

Rained a quarter inch in the morning through noon. The morning forecast underestimated the system. But it had been so dry the rain was soaked up quickly and the event was fine to be held. It was hot and humid until the sun went down and then cooled off nicely.


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[John1122]

Today/tonight's rain, which was the highest chance/flood hazard day, is a flop. It didn't rain enough to wet the road under trees here. There may be more upstream but we'll see how heavy it actually is.

[louise.caison233]

On 9/23/2025 at 2:25 PM, Carvers Gap said:

I will give it a go.  Hopefully, some of the Nooga folks will chime in.

Tough time of day to get a good grasp on.  Afternoon storms are a risk in this pattern.  Signal Mountain is also an entirely different ball game due to its elevation.  If it is anything like my area here in TRI, modeling will often miss things above 1500'.

Firstly, I am not a good short range summer weather source. I did check the RGEM, HRRR, and NAM 3k this morning for your local.  I think what you shared is probably accurate.  The RGEM is a hair earlier than 7PM.  

It is worth noting that modeling has been hit or miss with afternoon storms of late over E TN - i.e. not overly accurate.  A lot of these lines and cells have been slow movers.  By late morning or lunch today, if it were me...I would really keep an eye on short range, hi-res modeling which is derived from radar.

The Signal Mountain NWS point and click is this for the entire day (25% from 4-7PM)....

A 40 percent chance of showers and thunderstorms, mainly after 4pm. Partly sunny, with a high near 83. South wind around 5 mph becoming southwest in the afternoon.

 

Model trends can shift fast, especially on Signal Mountain. Afternoon storms are tricky, so I’d watch hi-res radar updates closely around midday.