Friday, June 20, 2008
Although we have been enjoying summer heat for nearly a month... technically it won't we summer until 7:59 tonight! That is when the sun will ascend to its highest latitude (Tropic of Cancer, 23.5 degrees north latitude) on the celestial sphere making today the longest day of the year in the northern hemisphere while it will be the shortest in the southern hemisphere.
One of the common questions we get in the weather department is why today is the highest point for the sun yet our maximum temperatures do not occur until July/August typically?
The reason is something called the 'lag of the seasons' and it is the same reason why it is hotter in the mid-afternoon than at noon. We receive our maximum insolation (the time when the maxiumum solar energy is deposited during the day at a point on the surface of the Earth) at midday and on the first day of summer when the sun is the highest in the sky. Because the Earth, the atmosphere, and oceans store heat they release it at a slower pace than they stored it up. Thus it takes about a month for us to see our highest temperatures on average. The same happens with the first day of winter being in December, but us not seeing out coldest temperatures on average until January.
You can learn more about the 'Summer Solstice' by clicking here.
Have a great Summer!!
Posted by Chris Smith at 4:29 PM
Thursday, June 19, 2008
With summer season in full swing it means folks are busy enjoying their neighborhood pools and lakes. While the winter rains helped ease the drought a little replenish many of our lakes, some remain low and continue to get lower. (Check the current lake levels here)
Lake Lanier peaked this spring at 1057.80' on May 24th. That was still more than 13' below full pool!! Since then the lake has dropped almost a foot to 1056.85'. One of the major reasons why is because now that we are into the summer season the sun evaporates nearly .2" of water every day. During the winter very little rain is evaporated because of the low sun angle.
You can do a simple experiment and notice the difference the summer sun makes. Pour a cup of water on the pavement in the sun and time how long it takes to evaporate. Then, pour a cup of water on the driveway in the shade. With full sunshine, the water evaporates much more quickly.
Even with above average rainfall during the summer it is very tough for the lakes to rise much because of the sun. The forecast for the area lakes over the month ahead shows Lake Lanier is expected to drop another foot! So, even with average to above average rainfall our lakes will drop. That's why is is so important that we all do our part to conserve!
A great resource for conservation is called Watersmart. They are a local organization committed to water conservation!
Have a great weekend and hopefully you will enjoy some of those scattered storms around the area.
Posted by Chris Smith at 3:14 PM
Tuesday, June 17, 2008
No, the moon is not ready to explode after a giant Thanksgiving feast, nor is it ready to crash into Earth. The giant moon you are witnessing this week at moonrise is called the 'solstice moon illusion.'
What is happening is your eyes are playing tricks on you! Scientists are not a 100% sure why and there are several theory's as to why it happens. The neat thing is that while the moon looks huge to you, it is actually a 'normal' size if you look at it through a camera lens.
The 'giant moon' is more apparent this time of year because when the sun is at its highest, the moon is at its lowest. With summer starting Saturday, that is the highest sun of the year and thus the lowest moon.
Although it was originally thought that the moon was being magnified by the atmosphere, we now know this not to be true because images of the moon on film are the same size regardless of elevation.
You can read more about this optical phenomenon and the theories as to why it happens by clicking here.
Also, here are the moonrise times for the days ahead.
Moonrise 6/17: 8:25 p.m.
Moonrise 6/18: 9:16 p.m.
Moonrise 6/19: 10:01 p.m.
Posted by Chris Smith at 8:58 AM
Wednesday, June 11, 2008
Just wanted to share this picture that a viewer sent me. It was taken by Kevin Turner in Hiram on Monday night. We had some very impressive electrical storms Monday night and Kevin, an amateur photographer, caught this strike. Notice how it forks across the sky and then you have the leader stroke hitting the ground.
If you would like to learn more about lightning and lightning safety just log onto our website at CBS46.com.
Posted by Chris Smith at 9:36 AM
Monday, June 09, 2008
The 2008 hurricane season is under way and we have already had our first storm, Arthur, which hit the Belize/Mexico coast last weekend.
The National Hurricane Center is predicting an above average season (see above graphic) for the coming year so we are expecting to stay pretty busy in the weather center. If we are lucky we might be able to get a nice tropical storm to give us some added rain in northern Georgia.
All hurricane season you can keep up with the latest on our website at cbs46.com. We have a special hurricane section where you can track the individual storms and get the latest hurricane news.
Posted by Chris Smith at 8:09 AM