Flash Flood Watch; Maybe Severe Weather Tomorrow.

Current Radar 

Today we broke the record high for December 27, 76°, laying down the 75° set in 1982.

Flash Flood Watch

Rain should begin sometime late tonight, last into the wee hours of the morning, and continue in full force into the afternoon. Note this is not expected to be a continuous rain, but we’ve seen so much these past several days, we can’t take much more and avoid a flooding event. (This is NOTHING like what we saw in May 2010).

The HRRR model illustrates:

Severe Weather Possible Monday

When:  Monday morning and early afternoon.

What: See this image, then keep reading.

How Bad? This event isn’t the magnitude/severity of last week’s big event, but that won’t matter to you if severe weather shows up on your front door. Wednesday’s event largely missed Williamson & Davidson Counties. This one may not. There is some reason for concern.

GFS, NAM12, and NAM4 forecast soundings for late morning/noon all show a low-end tornado threat.

The NAM4 model shows the heaviest storms in a broken squall line arriving around lunch.

These storms will be arriving in an environment potentially supportive of tornadoes, but more than that, damaging winds and maybe some small hail.

Of particular interest is the usually conservative SREF model. It’s an ensemble product and should be free from individual bias. It has a tornado-friendly environment here around lunch tomorrow as well. (Note, the below is for weather nerds. If you don’t know what it is, don’t worry about it).

The Storm Prediction Center has us just outside its Slight Risk outlook, but at the same time they suggested this risk could increase in the morning. They’ve held off on doing so until some uncertainties in the storm model (squall line vs supercells) resolve.

The other big “if” has to do with whether there will be enough instability in place. If there is, ample shear will support a meaningful severe weather event, so stay tuned. It’s a very difficult forecast.

For all these reasons, you should pay attention to the weather when you get up tomorrow. If you don’t have a wake-me-up app, click on the link at the banner below.

That rain/storm chance on Wednesday is trending down. Still looks like most, if not all, of that system will pass south and east of us.

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