Hurricane season isn't over yet, but cruise giant Carnival (CCL 0.13%) has so far avoided the massive weather disruptions that struck its core Caribbean destinations at this time last year. Investors are hoping that this good fortune might combine with healthy booking and travel trends to generate solid operating growth when the company announces its fiscal third-quarter results -- and updates its fiscal year outlook -- before the market opens on Thursday, Sept. 27.

Let's look at what's on tap in that report.

A cruise ship at sea.

Image source: Getty Images.

Sales growth

Carnival has surpassed management's growth expectations in each of the last two quarters. Net revenue yield, its core sales metric, expanded by 4.8% in the second quarter to mark an acceleration over the prior quarter's 3.9% increase. The company is enjoying modestly higher demand for cruises at increasing prices. Guests are spending more once they get on board, too, thanks to the rollout of ship upgrades like high-end restaurants and IMAX movie theaters.

CEO Arnold Donald and his team will let investors know how each of these trends affected results from Carnival's summer season. Investors will pay close attention to demand in the core Caribbean segment, which had been weak heading into the third quarter. That softness led to a conservative outlook for the second half of Carnival's fiscal year, and we'll find out soon whether the tamer hurricane season improved over the flat trend that executives had predicted

Keeping up with costs

Running a cruise isn't cheap, and those expenses include fixed costs like ship maintenance, along with the major variable costs like food, fuel, labor, and berthing fees. Carnival's earnings power essentially boils down to its ability to keep those expenses rising at a slower pace than the change in net revenue yields.

Last quarter, growth in costs accelerated to 3.6% from 1% in the prior quarter. But that was a stronger result than management had predicted, and it still translated into a healthy gap between cost and revenue gains.

Executives predicted that cost growth will tick up again in the third quarter, to between 4% and 5%, even as net revenue yield stops at between 2.5% and 3.5%. Investors shouldn't read too much into that difference, since Carnival expects a healthy gap between the two figures for the full fiscal year.

The updated outlook

Most vacationers book trips well in advance, which means Carnival usually has a good reading on its revenue expectations over the coming quarters. And with more than half the company's fiscal year behind it, including the seasonally strong summer months, management's updated 2018 outlook is likely to be fairly accurate.

Three months ago, executives said bookings for the next three quarters were running even with the prior-year period at higher prices. Rising fuel prices and currency exchange shifts, meanwhile, led to an earnings downgrade to between $4.15 and $4.25 per share, compared to the prior target range of $4.20 to $4.40.

Temporary profit swings tied to fuel costs shouldn't concern investors, but Wall Street is right to react to significant changes in Carnival's booking trends. After all, these reflect the company's competitive positioning and the broader health of the cruising industry.

If Carnival continues projecting steady booking volumes at rising prices, then the stock shouldn't see much volatility in response to this earnings report. But a change to that outlook, in either the positive or negative direction, will likely send shares moving as Wall Street scrambles to account for the shifting growth trend.