Sunday, July 6, 2008

Bertha Slowly Strengthening, Could Become a Hurricane

Tropical Storm Bertha has gained some strength this afternoon as winds have gone up from 50 mph to 60mph. At the same time, the surface pressure has dropped slightly from 1000mb to 998mb. When we observe tropical systems, there is typically a direct correlation between wind speeds and surface pressure. As pressure decreases, the wind speed increases and vice versa.

This is the satellite image taken from this afternoon. As you can see, Bertha has become better organized as there is a more concentrated area of showers and storms developing around the center of circulation. The heaviest convection is indicated by the yellow and orange colors. Those colors are indicative of the cloud tops. The colder the cloud tops, the brighter the color, and hence, the more showers and storms there are around the area of low pressure.

This is the best Bertha has looked in the past few days, which is why it has gained a little bit of strength.Tropical Storm Bertha will continue moving west and as it does so, will encounter some warmer sea surface temperatures. Warm waters often fuel these tropical systems, so with that scenario playing out, in combination with light upper level winds, look for Tropical Storm Bertha to possibly strengthen into a Category 1 Hurricane early this week.

When we look at the projected path of storms and the steering currents involved, we look at a plethora of computer models to see the most likely scenario of where the storm may head.
As you can see, these models take Bertha in a west-northwest direction over the next 2 to 3 days before they start to diverge in their own respective paths. Just like anything in weather, the farther you go out in time to forecast, the more uncertainty arises. The key will be when Bertha takes a northern turn. The earlier it happens, the better off everyone will be as it would completely avoid any landmasses. If it stays on its westward trajectory longer than the models expect, then that could pose problems to areas around Puerto Rico extending up to the Bahamas and Bermuda.