This week's question comes from Morning Brief reader Sarah: "Why are morning tornadoes so rare? They seem to primarily happen in the p.m. hours."

Tornadoes do indeed happen most often from late afternoon into early evening.

That’s because the severe thunderstorms that fuel tornadoes depend, in part, on warm and humid air near the ground.

On a typical day, the air is at its warmest around late afternoon after a full day of sun, and that’s when most severe thunderstorms usually develop.

On the other hand, it’s usually coolest right around sunrise.

So, there’s typically less instability available to fuel severe thunderstorms, particularly the supercell variety infamous for spawning stronger tornadoes.

But that doesn’t mean you can’t have morning tornadoes.

Sometimes lines of severe thunderstorms leftover from overnight that typically produce damaging wind gusts and heavy rain can spin up tornadoes within them, often hidden by heavy rainfall.

And if a tropical storm or hurricane is nearing landfall, tornadoes can spin up quickly in the storm’s outer rainbands, even if it’s in the morning.

So, yes, most tornadoes do happen in late afternoon or evening. But deaths from tornadoes at night are increasing and as we saw Thursday in New Orleans, they can certainly happen in the morning, too.