Next week, electric-car maker Tesla Motors (TSLA 0.79%) will report fourth-quarter results. With deliveries for the company's fourth quarter already reported, investors will likely turn to management's guidance for the current quarter to gauge where the company is at on its growth plan, and to see if the Model X is finally expected to begin benefiting sales.

Model X. Image source: Tesla Motors.

How many vehicles can investors expect Tesla management to say it expects for the current quarter?

Investor expectations are probably high
Ahead of Tesla's fourth-quarter report, one thing is clear: The company has big expectations for the full year. Management said in the company's third-quarter shareholder letter that Tesla was "highly confident" it could achieve average weekly unit production and deliveries in the range of 1,600 to 1,800 during the year -- and management specifically noted this metric represents an average across every week of the year, including holidays, factory tooling, etc. Weekly deliveries at this level amount to expected deliveries of about 83,200 to 93,200 units during 2016, or 65% to 85% year-over-year growth.

For the first quarter specifically, however, it's not quite as clear whether or not Tesla expects growth to be very robust. But whatever Tesla is expecting, investors' expectations for the guidance figure management will provide for the current quarter is likely high.

Not only do Tesla's expectations for a big year, overall, heighten expectations for the first quarter, but the Street may also be hoping to see the recently launched Model X to begin benefiting deliveries. With Tesla beginning deliveries of its Model X on Sept 29, the company will have had six full months to ramp-up production by the time the first quarter closes.

Accounting for uncertainty
Here's my take: While it's likely Tesla will guide for record deliveries in Q1, the guidance will probably take the form of a very wide range -- and the low-end of this range will likely only represent modest growth.

Why could Tesla's sales only grow modestly between Q4 and Q1?

First, Tesla's fourth quarter marked huge growth for the company. Deliveries were up 50% sequentially -- and the prior quarter was the company's previous record for quarterly deliveries.

While it's definitely possible that Tesla grows sales sequentially yet again after this big quarter of growth -- particularly with the help of the Model X -- it may be difficult to achieve anything more than modest, single-digit growth. Indeed, Tesla was in a similar situation going into its first quarter of both 2014 and 2015; after big prior quarters, the company's deliveries declined 6% sequentially in Q1 2014, and increased just 2% in Q1 2015.

Model S production at Tesla's Fremont factory. Image source: Tesla Motors.

Second, Tesla could be hitting the top of its current Model S production capacity -- and this would leave growth in deliveries for the quarter dependent on Model X production, which faces an uncertain ramp-up. On the other hand, a successful ramp-up of Model X could have a significant impact on deliveries toward the end of the quarter.

I'll be looking for Tesla to guide for about 18,000 to 21,000 vehicles in Q1, representing about a 4% to 21% sequential increase in deliveries. The company reports quarterly results on Wednesday, February 10, after market close.