It may be only be early October, but a nor'easter lies ahead for the East Coast. Here are the forecast details, including potential for wind, rain and coastal flooding for days.

Tropical moisture from the remnants of Priscilla will bring a multiday flood threat to the Desert Southwest starting today and peaking Friday into Saturday. Highest flood threat will be across central portions of Arizona and will include places like Flagstaff Phoenix, Sedona and Prescott. A widespread 1-3 inches looks likely with isolated totals as high as 5 inches. Please stay alert and make sure you have multiple ways to get warnings if you live in Arizona, New Mexico, Utah, Colorado and California. Click here for more on the timing of the rain.

The criteria for La Niña conditions have been met, according to NOAA’s Climate Prediction Center, and are expected to persist through the winter.

A mesmerizing new video from the European Space Agency lets you glide over Mars’s rugged surface, revealing a sprawling 800-mile canyon carved by ancient floods. Built from Mars Express orbiter data, the breathtaking animation captures twisting valleys, towering cliffs and a massive crater that tells the story of the Red Planet’s dramatic past.

Millions of people each year wait eagerly to see the leaves change brilliant hues of red and yellow. But do you know why the leaves put on this mesmerizing show each year? The secret is that these colors are in the leaves the entire time — but the shorter days and longer nights reveal them. FInd out exactly how this works and how weather plays a role here.