Atmospheric rivers are long and relatively narrow bands of water vapor that form over an ocean and flow through the sky. They carry moisture from the tropics to northern and southern latitudes, and can dump heavy rains or snow over land. According to the National Oceanic and Atmospheric Administration, they occur globally but are especially significant on the West Coast of the United States, where they create 30% to 50% of annual precipitation and are vital to water supplies but also can cause storms that produce flooding and mudslides.

It's almost time to catch summer's double meteor showers. The Southern Delta Aquariid and Alpha Capricornid meteor showers peak in the early morning of July 30. With minimal interference from moonlight, the meteors should appear bright and clear if viewed away from city lights. Each shower is expected to produce up to a dozen visible meteors per hour. The Alpha Capricornids may have tails that linger longer in the night sky. Viewing of each shower lasts through August 12. The next major meteor shower, the Perseids, will peak in mid-August.

Astronomers have discovered a strange new object in our Milky Way galaxy. The celestial object is emitting X-rays around the same time it's shooting out radio waves. Located 15,000 light-years away, scientists say this object could be a star, pair of stars or something else entirely. Findings were published Wednesday in the journal Nature. NASA's Chandra X-ray Observatory spotted the X-ray emissions by chance last year while focusing on a supernova remnant, or the remains of an exploded star. The hyperactive phase of this object appeared to last about a month.

Top weather agencies warn that the world should get ready for several years of even more record-breaking heat that pushes the globe to more deadly, fiery and uncomfortable extremes. Wednesday's five-year forecast from the World Meteorological Organization and the U.K. Meteorological Office says there's an 80% chance the world will break another annual temperature record in the next five years and it's even more probable that the world will again exceed the international temperature threshold set 10 years ago. Scientists say that means more heat deaths, wildfires, nastier hurricanes, downpours and droughts.