Forecast Blogs

Some Storms This Evening, Another Chance on Wednesday


Low Risk of Severe Storms This Evening

Storms moving in tonight have a low chance of becoming severe this evening. *If* they do, large hail and damaging winds will be the main threats. The Storm Prediction Center sees this as a low end threat and has placed us in probability of 5% of hail/damaging winds.

It appears the low probability is being realized. Storms are strong north of Nashville, but this should be the non event indicated by the low probabilities. We are watching it.

Tuesday Looks Great! 78°! Some Sun!

Evening update from David:

Wednesday Appears Stormy, Perhaps Severe

The big question is whether strong/severe storms will form west of us and get to us, or form east of us and run away from us.

The majority of Davidson and Williamson Counties are currently included in the Marginal Risk category with those to the east of I-65 being included in the Slight Risk category. We are right on the line. 

The bigger threat appears, right now, to be east of us. Please keep reading.

Below is the NAM3 model. Around 4 PM, it thinks storms will develop west us of, near the Tennessee River, then race east across I-65 around/after rush hour Thursday.

This is what the NAM3 has predicted in its last three runs. This model predicts the atmosphere will be very unstable, low cloud bases, SE winds turning S then SW the further up the atmosphere you go…all the things you look for in a severe storm setup, with mainly a large hail and damaging wind threat, with the lower possibility of tornadoes.

All that said, the above NAM3 model has a reputation for exaggeration, but it cannot (and should not) be discounted. The problem is, at this range, it’s one of the few high resolution models we have. Other models provide more information useful in predicting what might happen. One approach is to cram a bunch of smaller models, finds some consensus where possible, and displays it as the Short Range Ensemble Model (the SREF):

The SREF model sees a very high probability of a lot of instability to feed storms late Wednesday afternoon:

Dewpoints may be as high as 65° according to the SREF, which is concerning:

The SREF also sees a high probability of supercell development in west and Middle Tennessee Wednesday afternoon:

But, it’s not that easy. One large uncertainty is whether storms will actually form west of I-65 and move our way in this storm friendly environment. The GFS and Euro models also see development to our west that could sweep east and impact us.

The SREF thinks storm development is more likely east of I-65, and less likely west of I-65:

This matches the latest outlook from the Storm Prediction Center.

But, I see a slow trend toward the storms developing west of us, arriving late Wednesday afternoon/evening, with strong to severe potential.  I will be very interested to see tomorrow’s model data and the Storm Prediction Center’s take on this when the outlook is updated overnight.

This is a nuanced, uncertain forecast. There is potential for strong to severe storms, and potential that it will form east of us. I am not currently alarmed, but I might be tomorrow. Be prepared and stay tuned.

Showers Linger into Thursday, Sunny Skies Friday Through the Weekend

Thursday appears to consist of showers through a good bit of the day. Right now, no severe weather is anticipated.

GFS Model Loop 1 AM Thursday Through 7 AM Friday 

Once we reach Friday, clouds will begin to move along leaving us with sunny skies Friday through the weekend.

5-Day Allergy Forecast From Pollen.com



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