Forecast Blogs

Storms Possible Tonight, Updated Marathon Forecast

Current Radar

Tonight: T-Storms Late, Some Might Be Strong – 9PM 74°

Update: Based on the latest model runs this afternoon, a line of strong storms will be marching southeast this evening across Illinois and Kentucky before approaching the Tennessee state line.

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*One or two of these storms could be strong, and an isolated damaging wind gust or small hail cannot be ruled out.*

SPC Thunderstorm Outlook (…we are in a “general thunderstorm risk”, meaning the Storm Prediction Center doesn’t anticipate much, if any severe weather here)

Here’s what NWS Nashville had to say this afternoon:

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Timing: 9PM tonight through midnight

Hazards: Damaging straight-line wind gusts and hail

Confidence: The time-frame depicted by the HRRR model looks fairly accurate. While we do expect this line of storms to make it to Davidson and Williamson Counties, they will be likely weakening during their approach.

All-in-all, this is a very low end severe weather threat.

Follow @NashSevereWx on Twitter for updates on the approaching rain/storms tonight.

Wednesday: PM T-Storm Chances Increase, Some Strong – Wake Up 62° High 83°

The morning hours of Wednesday should start out mostly dry, with a few spot showers possible. These will be light and hit-or-miss.

Afternoon: We turn our attention to the western portion of the state, where a line of strong t-storms are expected to develop and move eastward in our direction.

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Update: As the sun sets, the approaching storms are expected to weaken. However, if these storms do have a better chance to be severe, they will develop and push through the area earlier in the afternoon/evening time-frame. Here’s why that timing is best for storm development:

  • CAPE (storm food): will be near 1500-1700 J/kg by late afternoon/evening. This is enough energy to support strong storms.
  • Increased forcing: a dry line will be located a bit further southwest, and this may aid in t-storm development upstream towards our area.
  • Low-level shear (change of wind direction and/or speed with height): this ingredient will be maximized around the 5-7PM time frame, so if storms move through then, our severe threat may be greater.

SPC Thunderstorm Outlook

We are currently located in a “marginal (“1″ on scale of 0 to 5) risk” for severe weather Wednesday.

Timing (subject to change): Showers and storms become likely after 4PM. Some could be strong to severe, moving eastward and weakening after sunset.

Hazards: Damaging straight-line winds and hail, “nearly zero” tornado threat

Confidence: Low. Why? It all depends on the storms that occur Tuesday night and early Wednesday morning. Will there be too much leftover cloud-cover and not enough time for destabilization of the atmosphere? Or will the sun return and prime our air for more storms, some possibly severe, Wednesday afternoon/evening?

Stay tuned for a more refined forecast tomorrow morning.

Thursday: AM T-Storms Move Out, Gradual Clearing – Wake Up 64° High 83°

Update: Rain may hang around through mid-morning Thursday before moving out. The NAM likes the idea of a “pop-up” shower Thursday afternoon, but I don’t buy it just yet. The main weather system should be moving well to the east by then, so any rain chances will be extremely limited.

Clearing should ensue by the afternoon/evening, as we look ahead to a dry Friday!

Extended Outlook: Unsettled Pattern Continues

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*Updated* Rock n Roll Marathon – Saturday Forecast

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A chance of rain and thunderstorms will be around during the St. Jude Rock ‘N’ Roll Run, however uncertainty remains in regards to rain coverage.

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If we were to rely 100% on current computer models (a bad idea — models are guidance, not gospel), it would be best to advise rain gear for the Rock n Roll Marathon on Saturday morning.

However, keep in mind that rain chances look to taper off a bit by early afternoon. So, any remaining outdoor marathon festivities have the potential to dry out a bit. Then, late evening into the overnight hours Sunday, stronger storms may return.

Summary: It looks wet Saturday morning. Timing, in regards to when we see a break in the rain on Saturday, is still uncertain since we are still several days away from the event. Overall, the weekend looks unsettled. Yes, there is a chance the run will be dry.

WE will continue to provide further updates on the stormy weather and Marathon forecast as the details become clearer.

This website supplements @NashSevereWx on Twitter, which you can find here.

Categories: Forecast Blogs