September so far is living up to its reputation as the market's cruelest month. Major indexes are uniformly negative so far, with the once-untouchable tech shares leading the way lower. Things don't get any easier, even though it looked like Monday was going to get off to a strong start. As Hurricane Irma tears its way through Florida, investors this week will need to keep alert for other storms out there as well. Three things to watch:

A surfer enjoys the waves churned up buy the approaching Hurricane Irma on September 9, 2017 in Miami Beach, Florida. Florida is in the path of the Hurricane which may come ashore at category 4. Getty Images

Assessing Irma

What is shaping up to be the worst hurricane in U.S. history hit the mainland Sunday, causing untold billions in damage to Florida and likely putting at least a temporary dent in the U.S. economy as well. So far, the consensus seems to be that any economic damage won't be lasting. But the possibility that third-quarter growth, at the very least, may slow down, could well throw a jolt into market behavior. Multiple economists have lowered their forecasts for third-quarter GDP, dampening hopes that the economy this year might achieve growth of around 3 percent. Wall Street is expecting any hit to be quick and bound to pass, but the precise impact is hard to determine at this point. "As far as hurricanes Harvey and Irma, there certainly have been consequential effects on people's lives. Bigger picture, though, major storms are a regular feature of American history (just think of Sandy and Katrina)," Brad McMillan, chief investment officer at Commonwealth Financial Network, said in a note. "Despite the damage they cause, they do not change the economy in a meaningful way. So as bad as Harvey was, and as bad as Irma may be, at the national level they should not result in significant changes."

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All eyes on Apple

Aside from Irma's destruction, the product rollout Apple has scheduled for Tuesday could well be the biggest event. Though you never know what's really going to happen at one of these things, speculation is that the company will be rolling out perhaps three new products, basically focusing on upgrades to the iPhone. A 3-D face-scanning camera could be in the works, as well as a wireless charger and no more physical home buttons, according to The Verge. As far as Apple shares go, they can be volatile on days like these. If the new plans aren't up to fussy fanboy expectations, the tech giant's shares could take a hit. In fact, venture capitalist and former Apple analyst Gene Munster last week predicted the stock could be teed up for a drop of 10 percent or more after its massive rise over the past year.

Delivering some Alpha

CNBC's annual "Delivering Alpha" conference starts Tuesday in New York and speakers at the conference have been known to move markets — or least individual stocks. Leon Cooperman of Omega Advisors, who will be at this year's event, a few years ago went 10-for-10 on stock picks. The conference features a textured mix of folks from the political, business and markets worlds, and will feature some legendary investors making individual stock picks. Among the featured guests: Treasury Secretary Steven Mnuchin, hedge fund kingpins Ray Dalio, Julian Robertson and Jim Chanos, and JPMorgan Chase CEO Jamie Dimon, among many others.

The last word