Upper-level winds have died down, so Falcon Heavy will try flying again
One Falcon Heavy rocket launched, three Falcon cores landed [Updated]

                      
                      
          7pm ET Update: Well, that was exhilarating. SpaceX's Falcon Heavy rocket launched at the top of its window on Thursday evening from Florida, and soared into space under clear skies. First, the two side boosters separated. And then the center core detached from the second stage, which carried its satellite payload on toward geostationary orbit.
Then, the fun began. In something of a space ballet, the two side boosters reentered Earth's atmosphere, and then made controlled burns to land within meters of one another at sites along the Florida coast. A few minutes later the center core, burning its engines hard, landed on a drone ship in the Atlantic Ocean.
Original post: On Wednesday evening, SpaceX ended its first attempt to fly the Falcon Heavy rocket and its Arabsat-6A payload in the middle of a two-hour launch window. The upper-level wind shear was unacceptable, and with a poor forecast, it just didn't make sense to load kerosene and oxygen on the rocket.

Now, the rocket is back on the launch pad for another attempt Thursday, with a similar launch window, opening at 6:35pm ET (10:35 UTC) and closing at 8:31pm ET (00:31 UTC). The upper-level wind forecast for this evening is considerably better.
This will be the Falcon Heavy rocket's second flight, following a successful first launch in February 2018, during which the company famously flung Elon Musk's cherry red Tesla Roadster into deep space. Starman is still out there, by the way, in an elliptical orbit around the Sun. Earth-based telescopes may be able to see him in the early 2020s, certainly no later than 2047.

          
                      
                  