Tuesday, September 11, 2007

DON'T GET TOO HAPPY


Everyone rushed to the window here at the CBS 46 studios in Midtown today (Tuesday, September 11), to see the spectacle - water falling from the sky. True, it wasn't a lot of rain, but the trees began to sway a bit and the spray was furious at times. There was even some high water at the bottom of the hill where 14th street runs into Northside Avenue. But then again - there's always high water there every time it rains because of poor drainage. A cold front was pushing toward Georgia, forcing cool air from Tennessee to collide into warmer air that's been over us since forever, it seems. In fact, before the rains fell, it was another very warm day with temperatures in the low 90s.

The front should linger over the southeast through the rest of the week bringing us a chance of rain nearly every day, especially on Thursday and Friday as waves of energy ride along the front, causing the air to rise, form clouds and then bring rain down to the parched ground. However, as my blog title implies - wet days won't last long and our drought isn't about to be over. And we can blame the prospect of extended talk of deficit on - La Niña.

The graphic above shows a patch of dark blue in the equatorial Pacific waters. This means the water there is cooler than normal. It's the opposite of the El Niño cycle in which the water is warmer. In the latter scenario, we typically expect more rain, stronger storms and even cooler winters in the southeast. But La Niña's detection will continue to divert the jet stream to our north and limit rainfall. The National Oceanic and Atmospheric Administration confirmed that La Niña is indeed occuring. Prior to that, it seemed to come and go, but NOAA says it's here to stay for a while. The two regimes take turns every 3 to 5 years in a cycle that scientists don't fully understand - they just know how to measure it.

How bad is it? Well this week, the State Climatologist David Stooksbury issued a La Niña Watch. In all the years I've been doing this job, I don't think I've ever heard of this prognosis. Sure, I know all about a Severe Thunderstorm Watch, advising of the imminent development of nasty storms. but I've never known any meteorological body to "watch out" for the likes of la Niña. Perhaps knowing that NOAA had declared La Niña made him confident to make such a declaration.

Here's a clip from Mr. Stooksbury's press release this week:


With the arrival of La Niña, there is a good chance that drought
conditions, currently ranging from exceptional across much of Alabama and Georgia to moderate in south Florida, will continue and possibly worsen throughout the winter and into next spring.

If below normal rainfall occurs during the cool season, moisture
recharge of groundwater, soils, ponds and reservoirs will be limited.


Southeastern states depend on water recharge during the cool season.

Farmers who plan to plant winter forage and do not have irrigation
capability have a high risk of being seriously impacted by the winter drought.


In addition the risk of increased wildfires should be expected during the winter and spring wildfire season in Florida, south Georgia, and lower Alabama.

To be fair, Mr. Stookcbury doesn't act alone. He's part of a group called the Southeast Climate Consortium, an association of climatologists and researchers from various universities. They're just giving everyone a collective "heads up".

So enjoy the rain this week; it should be gone by late Saturday and dry and sunny weather returns Sunday.

No comments: