Mark Rogowsky:

The numbers at first glance don’t seem quite so bad as BMW and Mercedes are both registering double-digit sales increases for 2013. But a deeper dive (thanks to GoodCarBadCar and the California New Car Dealers Association) paints a different picture. As the accompanying chart shows, five competitive vehicles are all down significantly against their 2012 sales numbers. Given that overall U.S. auto sales are up by 7.7%, and 12.5% in California, the performance of the Mercedes E-Class, the BMW 5-Series, and the Lexus GS are especially disappointing.

But it’s in the BMW 7-Series and Porsche Panamera that the presence of the Model S is probably being felt most acutely. Both are performance luxury sedans capable of seating families comfortably and both are fairly commonplace in the wealthy neighborhoods of the San Francisco Bay Area. Those neighborhoods are now rife with Teslas. More than 4700 Model S registrations have been recorded in California and at least some are coming at the expense of the competition. Nationally, the Tesla has matched the total sales of the Lexus LS, Audi Audi A8 and Panamera combined.

It’s certainly true that for the moment, BMW and Mercedes are still going to sell plenty of cars. Together, their midsize sedans will have a 5:1 edge over the Tesla in 2013, and much greater if you also include the large sedans in the mix. But by the end of next year, Tesla hopes to double production and deliver as many cars outside the U.S. as it’s selling here. The competition is clearly heating up.