2 twisters reported near Galveston, Texas.

Rare linking of two jet streams brought extreme winds and rain to U.S midsection.

Air quality has been affected nationwide.

New volcanic ash monitoring techniques will aide air traffic safety.

Data shedding light on auroras, how solar wind and Earth's magnetic field interact.

11 days after its launch, NASA's NPP satellite sends back its first science data.

NASA's NPP satellite gets a complete view of our planet every day.

Hurricane-strength winds spark wildfires, flip trucks.

Gigantic jets shoot from clouds to upper atmosphere.

The top five most lightning-prone states.

A year's worth of snow dumped on Seattle in one day.

If the dip below zero comes after midnight, it will set a new record.

First major storm since 1984.

NASA satellite spots swirling cyclone from space.

The stunning Oct. 24 northern lights display reached as far south as Arkansas.

Noctilucent clouds grace skies in summer months around dusk.

So-called noctilucent clouds are often on display for orbiting astronauts.

From floods to fires to tornadoes, records fell while damage mounted.

The strengthening La Niña in the Pacific Ocean brings with it a host of possible trends as outlin...

Summer in the Northern Hemisphere is officially over.

A look at our planet as it turns toward the New Year.