Weather apps on the iPhone and the Google Pixel don't show the risk of impacts from Hurricane Florence just days before it's expected to reach the Carolinas. Instead, they forecast partly cloudy skies, relying on the same computer model. Matthew Fortner/Staff

A dangerous storm is barreling toward the Southeast, more than a million people have been told to evacuate South Carolina’s coast, and if you checked your phone’s weather app, you’d hardly know it.

Hurricane Florence — a Category 4 monster — isn’t forecast to make a direct hit on Charleston, but heavy rain and riptides are expected to rush into South Carolina all the same. Tropical storm-force winds are likely, too.

But ask Siri or open the iPhone’s default weather app and you’ll probably see a forecast that calls for partly cloudy weather or a chance of thunderstorms at the end of the week. Google’s Pixel phone doesn’t carry a warning either: It calls for a chance of storms on Tuesday and Wednesday — but not on Friday, when Florence is expected to make landfall.

Other apps have led a steady drumbeat of warnings. The state’s Emergency Management Division sent an evacuation notice through its app. Word of the order, which covers the entirety of South Carolina’s coast, was likewise pushed out by news organizations like The Post and Courier and The New York Times.

And over the weekend, state officials sent a mobile phone alert along the coast, urging residents to start getting ready.

The weather apps didn’t change course. That’s because their forecasts are based on a single model, and it’s pieced together automatically, without curation by meteorologists sifting through dozens of predictions from multiple computer models.

And they don't show watches and warnings until the storm was close: The National Weather Service doesn't issue those advisories until a hurricane is two days away. Pixel phones began showing a hurricane watch on Tuesday, but iPhones did not.

The one-source apps work just fine most of the time, said Jared Smith, who runs @chswx, a Charleston Weather account on Twitter. When you face a decision about whether to bring an umbrella or not, you’ll do fine with a computer-generated prediction based on one model.

But when the questions are more urgent — leave town or stay, stock up on supplies or not — Smith said your phone’s partly cloudy guess won’t do. And even if most residents are following the storm’s progress more closely, he thinks an icon of sunshine can sow uncertainty.

"It was confusing a lot of people," said Smith, who has fielded a deluge of questions about Florence’s every movement. "I get really concerned about that."

Apple and Google’s apps get their data from The Weather Co., the IBM-owned meteorology firm that runs The Weather Channel. Spokeswoman Melissa Medori said the company doesn’t control what shows up on smartphones. It just provides the data.

"The default apps use The Weather Company data, but what shows to consumers is up to that partner," Medori said.

For its part, Medori said, The Weather Channel’s app has featured Florence prominently for several days. That tracks with Smith’s suggestion for improving Apple and Google’s apps.

Smith, a software development manager by day, said he’d prefer that the smartphones’ default apps at least acknowledge the storm off the coast and guide users to more detailed forecasts or news coverage.

It’s not clear whether the smartphone makers will heed his advice: Apple and Google didn’t respond to questions about how their phones display the hurricane threat.

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Reach Thad Moore at 843-937-5703. Follow him on Twitter @thadmoore.

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