Ever since I was a youngster, I have used the term "gully washer" todescribe a summer downpour. Right after we got one, my brother and I would rundown to the brook to watch all the water rush by. It's amazing how just alittle trickle of water a foot or so wide turned into such a formidablecurrent. We had enough common sense to stay out of it, and I would encourageyou to do the same. Never try to drive through or walk across fast-movingwater. Most people that attempt this feat do make it, but there are always theones that don't.Speaking of downpours and flash floods, there have been and will continue to besome gully washers in the Southwest. These storms are fueled by tropicalmoisture from the south and plenty of daytime heating. What makes these stormsso dangerous is that the water rushes through canyons and ravines often toplaces a good distance from where the heavy rain happened.
A word to the wise: If you are driving or camping in the Southwest and noticebig thunderstorms around, don't linger in the low spots. Flooding in this partof the country happens quick. That's why it's called flash flooding.
So why don't these downpours happen in May and June? The weather in theSouthwest is hot then, but it tends to be a rainless period. The reason is thatthere is simply very little moisture in the air. When the humidity is under 15percent like it is in May and June, the hot surface air still rises but thereis nothing to condense out of it.
Story by AccuWeather.com Senior Meteorologist John Kocet
