It took longer than expected but Isaac has reached hurricane strength. You can even see an eye that has formed in the center of the storm. Isaac has continued to slowly intensify over the past few hours and has formed a partial eye. The reason this has taken so long to happen was mainly due to the size of the storm and dry air that kept getting sucked into the center. Larger storms take a longer time to intensify and dry air prevents thunderstorms from reaching their full potential. The storm will remain a hurricane and now we will have to watch to see just how strong it gets before landfall late tonight and early Wednesday morning. There are two images below of the storm. I love the second image as it was taken just as the sun was rising over the storm. Notice the textured white areas on the photos. Those are the big thunderstorms rotating around the center of Isaac. For more insight and to ask questions about the weather find me on Twitter at @growingwisdom
Damage so far
Very few in the national news are talking about the flooding across south Florida. Some towns are under water, roads are washed out and people are stranded. Canoes had to be used by folks around the Lake Worth area of Palm Beach County to get around. The flooding will be receding overnight, but may be a sign of what is to come in and around New Orleans over the next two days.
Current track and projections
Issac is moving northwestward through the Gulf of Mexico landfall is expected in the early morning hours tomorrow just west of New Orleans, Louisiana. Isaac should still be a category 1 storm at that time but will have to be monitored for stronger intensity throughout the day.
How much rain?
Rainfall will be close to a foot northwest of the eye’s landfall. You can see on the image below that there is little rainfall in the eye, (center) but increasing amounts of rainfall predicted away from the eye. They key to how much rain falls is on the right side of the image. The storm is forecast to move very slowly and this will allow the rain to fall for a longer period of time. Flooding is certainly going to be an issue in many areas in the path of this storm.
The remnants of the storm will eventually move into drought stricken areas of the Midwest. This is good news for farmers who might be able to save some of their fall crop but unfortunately will be too late for most. However, just begining to end the drought across the center of the Country is a good thing. Winter wheat and other crops will do better if planted in moist soil.
Damage from the storm
Tropical storms and minimal hurricanes can cause a tremendous amount damage. Vermont saw some of its worst flooding in a century from tropical storm Irene. It’s impossible to predict how much damage this storm will cause. The good news is that billions of dollars have been spent to upgrade the levy system in New Orleans. This won’t be a major test of that system, but a test nonetheless.
Why do hurricanes form?
You might wonder why these storms form in the first place. I tell my students that hurricanes are nature’s way of moving excess heat from the tropics to the northern latitudes. From about June through October, the oceans in the tropics are very warm. The water temperatures must be in the 80s not only at the surface but several feet below as well. This temperature structure to the sea only happens in the warm months. As the sun evaporates the ocean water that warm moist air rises and can, if conditions are favorable, create thunderstorms. In some cases, these clusters of thunderstorms will group together and begin to rotate. The rotation can be attributed to something called the Coriolis force. The Coriolis is strongest at the poles and zero at the equator. This is why hurricanes don’t happen on or within several hundred miles of the equator. (no Coriolis=no spin) Winds inside the thunderstorms stir up more ocean spray which then evaporates and continues to feed the storms. If the winds reach 39 mph, the storm is called a “tropical storm.” And when the wind speeds reach 74 mph, the storm is officially a “tropical cyclone,” or hurricane.
Once the storm becomes a hurricane they are then categorized into 5 different levels of strength. Category 5 is the strongest and the last time one of those actually hit the United States was in 1992 when hurricane Andrew came ashore south of Miami.
Gardening tip this week
This is a great time of year to plant. I actually feel that for many plants fall is a better time to plant than it is in the spring. Since the ground stays warm well into October, roots have a good chance to become established. When you plant in the spring, much of the energy of the plant goes into making new leaves, not new roots.
If you have a tough spot that you can’t seem to grow anything, check out this video and learn about some of the plants that actually thrive in hard to grow conditions.
I’d love to hear your thoughts on this blog or any others. Please follow me on Twitter at @growingwisdom and check out my latest videos at GrowingWisdom.com