Showing posts with label Floods. Show all posts
Showing posts with label Floods. Show all posts

Wednesday, May 5, 2010

El Niño, NAO Fade Fast... So What's Next?

Two Major Weather Phenomenon Losing Presence as Climate Variability Now Rules

For the past year we've blamed any and every weather extreme on El Niño and its interaction with the North Atlantic Oscillation (NAO). Wait, the NAO? Look, I'm not just talking to myself again. The NAO was really present this past winter and it, along with the famous El Niño warm-water effect in the Pacific Ocean, sent moisture-soaked air up from the Gulf of Mexico as a linebacker high pressure block kept the jet stream on a steady ride up the East Coast, therefore forcing Arctic air deep into the South and throwing a plume of wintry precipitation along the I-95 corridor.

The result: record-breaking cold east of the Mississippi, powerful and damaging tornadoes in the southern plains, dozens of snowstorms and even several epic blizzards across the Mid-Atlantic and Northeast, and historic flooding in the Ohio Valley.


But what about this past weekend's torrent in Tennessee, which caused the city of Nashville to become water-logged, causing the famous Grand Ole Opry to flood? Well, climatologists say that El Niño has weakened so much already that it likely had very little impact on the event, and the NAO has pretty much spun itself out by now. That said, our weather pattern is now largely going to be affected by climate variability, or pretty much whatever happens, happens.

Ever-changing and unpredictable! This blog post has been brought to you by reason # 198,765,499,876,534 why I love weather! Enjoy it, it's the only weather you've got!

Monday, May 3, 2010

Severe Weather Awareness Week

Severe Weather Awareness Week kicked off this past weekend for the New York metropolitan region, and what better time than now to help explain some of the lingo you’ll often hear from weather forecasters across the nation during one of the most violent weather months of the year.

May is considered the heart of tornado season, but it’s not all about tornadoes, ya know... Over the last 20 years a variety of severe weather events has killed over 100 people in New York state alone, and has caused over three quarters of a billion dollars in damage. On average, the National Weather Service (NWS) issues 400 severe thunderstorm warnings, 17 tornado warnings and about 150 flash flood warnings each year in the Empire State. So, next time you hear word of any of these warnings, remember these definitions:

A severe thunderstorm watch is issued when severe thunderstorms capable of producing winds of at least 58 mph and or hail of at least one inch in diameter, are possible within the next few hours (typically less than six hours).

A severe thunderstorm warning means that severe thunderstorms are imminent or occurring, and could pose a significant threat to life and property.

A tornado watch means conditions are ripe for tornadoes to form and they could do so within the next few hours (typically less than six hours).

A tornado warning means a tornado is imminent or occurring, and has likely been visually spotted or indicated by Doppler radar. A tornado warning implies an immediate threat to life and property and appropriate shelter should be taken immediately.

A flash flood watch means conditions are favorable for flash flooding, which is a rapid rise (typically within six hours) of water along a stream or low lying urban area, most commonly resulting from downpours associated with severe thunderstorms.

A flash flood warning means flash flooding is imminent or occurring and flood waters can rise rapidly, if they have not already.