Rain and Storms Late Tonight & Late Friday Night

Current Official Hourly Observation (taken at :53 on the hour)

Current Radar Loop

Temps & Rain Probabilities Next 36 Hours (auto-updating)

Updated at 4:15 PM

The pattern we’ve seen over the past few weeks: north and northwest winds — which delivered below-average temps — has broken. South winds are taking over. This means warmer temps with rain/storms.

ThursdayWind Advisory, Rain Tonight – Low 60s/Upper 50s

Winds were already gusting over 30 mph this morning. Winds will strengthen this afternoon (Gusts – Dark Blue; Sustained Winds – Purple):

A 46 MPH wind gust will create problems for large trucks and high-profile vehicles during the evening commute. Be careful!

A Wind Advisory remains effective through 4 AM Friday:

from A Mighty Wind

Rain & Thunderstorms will continue to linger around Middle TN. Super-dry air near the surface has been preventing a lot of the rain from reaching the ground. You may see a few sprinkles (ProTip: the wind will LOL at your umbrella), but it’ll be nothing like what we see tonight.

Tonight, legit rain arrives. Here is the HRRR model from 7 PM until 4 AM:

Notice that squall line that comes through in the middle of the night. We’ll keep a close eye on that.

This rain will continue off and on (mostly “on”) into Friday morning. A few thunderstorms are possible, but severe weather is not expected at this time, We’re very curious to see how potent that wee-hour line of storms will be.

We aren’t sure exactly when the rain will stop, but the best thinking is before mid-morning. Rainfall totals will range between 0.70″ and 0.80″. That’s enough to rainout outdoor activities.

FridayRain/Storms – AM Low 55, PM High 68

After the morning rain/storms push east, most of the daylight hours should be rain free, although we could still see a shower or two.

All eyes are the weather Friday night.

Yesterday, the Storm Prediction Center included us in its “Slight” (think “elevated”) Risk area for severe weather. Today, SPC shifted that area out of Middle Tennessee.

Just because we are not included in the “Slight Risk”, does not mean we are out of the woods completely with this system. SPC still includes us in the 5% chance area of severe weather happening within 25 miles of you:

Screen Shot 2014-03-27 at 3.39.41 PM

Why the shift? One big reason is the forecast track of the surface low pressure center: if it goes north of us (and we get the southern side of it), we’ll see a good chance of severe weather.

However, we think the low pressure will still be developing and pass over/south of us, putting us on the northern (or “wrong”) side for severe weather. This is what the GFS/Euro models think will happen:

Hence the downgrade from a Slight Risk.

Another potential limitation on severe weather tomorrow will be any thunderstorms which may occur to our south: along I-65 and into the northern Gulf of Mexico. To get severe weather tomorrow, we’ll need an uninterrupted pipeline of south winds blowing in all that warm, wet air north from the Gulf. Any thunderstorms which develop along the way will block the pipeline and limit our severe weather chances.

Nevertheless, even if they aren’t severe, there will be rain and a few storms Friday night/overnight.

The Hi-Res NAM model delays the heavy stuff until 1 AM Saturday, maybe later:

The GFS agrees. Here it is at 1 AM Saturday:

Rain should end around dawn Saturday morning, but not before a grand total of around 1.5″ of rain will have fallen:

Friday night (especially early in the evening) may be relatively dry, but by Saturday morning, it looks like soccer/baseball/anything that requires a ball to roll on grass or dirt will be rained out.

A rain out looks likely at Rod Cook Field Saturday:

The cold front triggering all this rain will slice into temps a bit, but nothing like what we’ve seen the past few weeks.

Official Extended NWS Forecast: 

Screen Shot 2014-03-27 at 3.47.15 PM

This website supplements information found @NashSevereWx on Twitter.