It's shaping up to be quite a month for stocks. We're on track for the best October trading in a decade now. The big S&P 500 index is up 7.8% since the calendar flipped from September.

At this point, only 2011's year-end pop has been bigger than the upside investors have enjoyed month-to-date. And with earnings season in full swing this week, we could see even bigger numbers posted by the time October is out.

To take advantage of the bullish sentiment in stocks this week, we're turning to a fresh set of Rocket Stocks worth buying.

For the uninitiated, "Rocket Stocks" are our list of companies with short-term gain catalysts and longer-term growth potential. To find them, I run a weekly quantitative screen that seeks out stocks with a combination of analyst upgrades and positive earnings surprises to identify rising analyst expectations, a bullish signal for stocks in any market. After all, where analysts' expectations are increasing, institutional cash often follows. In the last 321 weeks, our weekly list of five plays has outperformed the S&P 500's record run by 78.14%.

Without further ado, here's a look at this week's Rocket Stocks.

Costco Wholesale

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$68 billion retailer Costco Wholesale (COST) - Get Report  is showing investors some strong performance in 2015. Since the start of this year, shares have managed to climb about 10% higher, beating the S&P's barely breakeven performance over that same timeframe. And this month, as Costco presses up against new all-time highs, it still makes sense for investors to take notice.

Costco's model is different than most conventional retailers. You see, this big box store chain doesn't actually make any money on selling items. Instead, Costco earns the vast majority of its profits through membership dues, an extra high-margin revenue stream that enables Costco to sell its merchandise very close to cost. Only Costco's 80 million paid-up members get to shop at the firm's 686 locations. That model has been effective enough to make Costco the third-largest retail chain in the U.S. from a sales standpoint.

Costco's membership model also creates extremely sticky customers. With a sunk annual cost, customers are more likely to shop at Costco, and they're less likely to spend the membership fee at a competing wholesale store. Financially speaking, Costco is in excellent shape, with approximately a quarter-billion dollars in net cash on its balance sheet. That lack of net debt means that Costco has an added safety net if times unexpectedly get tough.

Facebook

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No doubt about it, Facebook (FB) - Get Report  has been on fire this year. So far in 2015, this $288 billion tech giant has managed to rally more than 31%, leaving the rest of the S&P 500 in its dust. Facebook is the biggest success story in social networking stocks. The firm boasts more than 1.4 billion monthly active users, making it the single most-trafficked website on the internet today.

Facebook has some built-in advantages that make it a powerful tool for marketers. Because users' profiles contain a treasure trove of demographic and preference information, and because users self-select networks of friends, Facebook owns a powerful marketing tool that they've only begun to monetize. Likewise, those detailed social networks create a valuable moat for users too. Consumers are less likely to invest the necessary time into creating a new profile on a competing upstart platform. As advertisers look to target consumers more narrowly than ever before, Facebook is uniquely positioned to give them the best bang for their buck.

At this point, Facebook's monetization is still in the early stages. While an increased focus on mobile has been a huge step in the right direction, the firm still generates most of its revenues here in the U.S., a geography that accounts for a tiny portion of global traffic today. If Facebook can extrapolate its financial success in the U.S. onto new markets, look for substantial revenue generation in the quarters and years ahead.

Southwest Airlines

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The last few years have been fantastic for airlines, and record-low oil prices, low interest rates and renegotiated deals with labor unions have brought the industry off of cyclical lows. And while the strong performance at the legacy carriers may have distracted some investors from Southwest Airlines (LUV) - Get Report , this Dallas-based carrier remains the best-in-breed airline stock.

Southwest is the pre-eminent discount carrier. The firm's point-to-point network reaches almost 100 destinations - including five international routes. Southwest's operation of a single airframe across the entire fleet -- the Boeing 737 -- has been an important driver of cost savings, as has its willingness to upgrade the fleet with significantly more efficient 737NG models and the upcoming 737MAX. That model is a far cry from the approach that the hub-and-spoke legacy carriers have taken, and that's a big contributor to Southwest ability to give investors a profit every year for more than four decades now.

The introduction of further, more lucrative routes, such as Hawaii, Cabo and Cancun, provide a big potential profit boost. So should new innovations in aircraft -- the introduction of new seating options and onboard bag storage should increase revenues per passenger mile without sacrificing customer comfort.

With rising analyst sentiment in Southwest this week, we're betting on shares.

Paccar

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Commercial truck maker Paccar (PCAR) - Get Report  is another Rocket Stock to keep an eye on in the months ahead. While low oil prices have proven to be a challenge for Paccar in 2015, delaying some spending on more efficient fleet upgrades, those low fuel costs have also been increasing truck transport volumes. That's driven trucking companies too expand their fleets to cope with extremely high truck utilization rates.

Paccar builds trucks under the Peterbilt, Kenworth and DAF names, selling vehicles through a network of about 2,000 dealers worldwide. The firm's brands are well thought of in the industry, giving it an edge that's hard for newcomers to compete with. A shift to internal component development (like engines) should spell higher long-term margins for Paccar. Today, the firm builds almost half of its heavy truck engines, up from zero just four years ago.

Financially speaking, this stock has been performing well, even if its stock hasn't been doing the same until now. Paccar's revenue is on track to hit a record in 2015, and margins have been steadily moving higher as well. The possibility of higher rates and higher oil prices should put some pressure on truck operators in 2016, particularly as they enjoy higher profits; shippers won't want to miss the opportunity to upgrade to materially more efficient fleets while they can afford to do so. Paccar benefits immensely under that scenario.

Adobe Systems

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Last up on our list of Rocket Stocks is Adobe Systems (ADBE) - Get Report . Adobe makes the number-one tools for creative professionals in the digital world -- the firm's flagship content creation applications include Photoshop, Acrobat, Dreamweaver and After Effects, which are used by creative professionals the world over to create images, videos, page layouts and Web sites. By establishing itself as the platform of choice for creative professionals, Adobe has been able to capture a lucrative and sticky customer base.

But the firm has been in the process of a major transition in the last several years, moving from a one-time license model to a cloud-based software subscription. The firm's Creative Cloud product gives customers the latest version of its software suite at a recurring low cost. That low barrier to entry should help Adobe curb piracy and court more price-conscious customers -- and it should generate bigger lifetime revenue from paying customers thanks to its ongoing license model.

For Adobe, the subscription model gives the firm smooth revenues, spreading sales across the business cycle and not just when a big new upgrade hits store shelves. It's not always easy to convince existing customers that they should keep paying you in perpetuity, but Adobe has found great success in converting its user base to the cloud. Expect more progress when the firm reports its fourth-quarter earnings numbers at the end of this year.

Disclosure: This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.