It was 72 already at 11 am this morning, so I’ve upped the ante to 76 this afternoon. 72 already ties the record, 76 will obliterate it! This one is 134 years old!

Showers push in tomorrow as we begin a gradual cool down.

If you were with me here last night or watched News 2 at 10pm, I noted that the newest model runs were showing a chance for rain to change to snow Saturday afternoon and evening. I also noted that it’s too early to get carried away as the models can flip flop. Here is the latest. Below is the newest GFS/AVN run valid Saturday at 6pm (00z Sunday):

The top map is isobars and thickness lines. The bottom is 6 hour precip and 850 millibar temps. The isobars outline the Gulf low that passes through Mississippi and Alabama into northern Georgia. The temperatures are too warm at first for snow in Nashville. But as the low passes by, and the cold air drops in, this model run still indicates a changeover to snow Saturday afternoon and evening. It may begin as snow in northwest Middle Tennessee and/or West Kentucky where temps are initially colder. The above map shows the 540 thickness line (actually 5400 meters, usually the rain snow line) getting past Nashville by Saturday evening, as well as the freezing line at 850 millibars (about 5,000 ft) shown on the precip map.

Once again, it is way too early to get carried away, much less attempt to forecast amounts, but I know you want to see the latest!

To learn more about “thickness lines” read below:

This represents the thickness in meters between the 500 mb pressure surface and the 1000 mb surface. This is directly related to mean layer temperature and is often used to determine precipitation type. The 5400 thickness line is often referred to as the rain/snow line. Also, it is also known that surface pressure systems tend to move along thickness lines.

We’ll have enough sunshine and warm south wind (gusty at times) to push the temperatures into the mid-70’s. That would qualify as a record high (the mark of 72 was set way back in 1873) for this date. There will also be some sunshine today for the first time in awhile. This remarkable weather won’t last- rain is back in the forecast tomorrow and Wednesday; by this weekend we’ll have a high on Saturday only in the 30’s with some snow possible!

As mentioned in my entry below, we could break a 134 year old record on Tuesday. Rain and a few storms return on Wednesday and Thursday as colder air pushes in. A second push of cold air should push in Saturday, and the newest model runs just out in the last 10 minutes (as of 10:20pm) show a Gulf low passing to our east which could bring a change from rain (or a mix) to all snow Saturday afternoon and evening. It’s awfully early to get too carried away with that forecast, as the models flip flop quite often. But I know you want to know the latest. We’ll follow that as the week wears on and keep you posted.

As our front once again returns northward as a warm front, we may break another record on Tuesday. This one is 137 years old!

The bigger rains and cooler weather will be just to the north today. Most of middle Tennessee will at least see a passing shower or two. I expect the daytime heating to the south to produce a few thunderstorms as highs will reach in the 70’s today in the southern third of our area. Meanwhile north of Nashville highs will likely stay only in the 50’s all day. The rain chances start to diminish tonight. With a little sunshine tomorrow and gusty winds will break another record high (we broke one yesterday in Nashville) with temperatures reaching in the mid-70’s! By Friday we’ll have highs only in the 40’s.

Sunday’s 73 degrees shattered a 55 year old record as you can read on my previous entry. We may scare a few more high temperature records later this week (see 7 Day Forecast to the right).

On Monday, a cold front will temporarily enter Middle Tennessee before returning northward as a cold front. As it puts the breaks on in our area, it should create quite a temperature difference from northwest to southeast. It also will be the triggering mechanism for showers and thundershowers.

On Tuesday, that front high tails it northward putting us back into 70s once again.

As of 2pm the temperature in Nashville was 73 degrees. It might slip higher, though some showers have passed near the airport to push the temp back. Expect increased rain and t’shower chances tonight and tomorrow as a cold front briefly pushes into the area on Monday, before returning northward as a warm front.

The good news: temperatures are in the 60s this morning and should hit the low 70s this afternoon. Today’s record high is 71 set back in 1952; it’s unusual to be this warm in December.

The not-so-good news: it will be mostly cloudy and a passing shower or thundershower is possible. That chance is 30% in Nashville but higher to the west for towns like Clarksville, Paris, Dover, Waverly, Erin, Hopkinsville.

Our headache-inducing stationary front will settle back over the area tonight and tomorrow. We’ll mention clouds, occasional showers and temperatures in the 50s for Monday. We should clear out on Tuesday and return to the low 70s, but that’s short-lived. The same front (and moisture) returns on Wednesday before a cold front brings thunderstorms on Wednesday night into early Thursday. Behind that system, we finally clear out (and get chilly). Check the seven day forecast for details.

With a warm front pushing up from the south, we expect temperatures to reach about 72 on Sunday. The record high is 71 set in 1952. This evening in Nashville, there will still be fog and mist around so drive carefully. But notice on the satellite view above that on the other side of that warm front there is a little more sunshine. That’s what is headed our way. We will still have a few scattered showers around on Sunday, but more sunshine and record warmth will make for a better day compared to the foggy and misty Saturday we just had.