steve cross loves music and science

I’ve been holding off on blogging about this, but since I’m heading out of town tomorrow, I feel I must mention it today. There’s actually a decent chance of some measurable snowfall on Christmas day this year not only in Nashville, but in most of TN, and even some states south of TN. Here are the official statistics on a white Christmas in Nashville, from the National Weather Service:

THERE HAVE BEEN ONLY NINE CHRISTMASES WITH MEASURABLE AMOUNTS OF SNOW SINCE SNOWFALL RECORD KEEPING BEGAN IN NASHVILLE BACK IN THE WINTER OF 1884 AND 1885. THE LAST TIME MEASURABLE SNOW FELL ON CHRISTMAS DAY IN NASHVILLE WAS IN 1993 WHEN THREE TENTHS OF AN INCH WAS MEASURED. TRACE AMOUNTS OF SNOW FELL ON CHRISTMAS IN 2002. STATISTICALLY THERE IS ONLY A 7 PERCENT CHANCE OF MEASURABLE SNOW ON ANY GIVEN CHRISTMAS. THE MOST SNOW EVER TO FALL ON CHRISTMAS IN NASHVILLE IS 2.7 INCHES IN 1969.

The storm system that has been contributing to the unusual rainfall in southern California will be sliding across the southwestern states today and tomorrow, and joining with an upper level disturbance from the north. The upper level disturbance will be providing the cold, while the low pressure system to the south will be providing the moisture.  As the two combine, moisture will be spread north of the low pressure system over the gulf coast on southerly winds, which will bring enough warm air to change the precip to rain on Christmas eve day, but that night the cold air from the upper disturbance will take over and switch it back to snow, which should continue into at least Christmas morning. From what I’ve read, the models are in fair agreement on the timing of the whole thing, but not on the amount of moisture (read: depth of snow) involved. So we’ll have to wait until probably this time tomorrow, or even tomorrow night to really get a good grip on snow amounts. Even then, models can only go so far. I wouldn’t get my hopes up for any “deep” snow though, I’d be very surprised if Nashville got more than 2 inches. I will be with my family in northeast TN, so this will all happen about 6 hours later than Nashville, but naturally there will probably be a little more snow there, and I have every intention of taking a trip to the mountains where there’ll be a lot more snow. Maybe even go skiing.

I may find something to blog about over the weekend, but this will probably be my last post until next week. So Happy Holidays!