And so it began. The first true Atlantic storm of the 2008 season grew from a wave that emerged off of the east coast of Africa. Bertha, by name, was a surprise to all of us as it grew from a tropical wave into a Category 3 storm. There were two dilemmas that faced forecasters as they wrestled with a hurricane that formed so early in the season in the eastern Atlantic. 
First, there was the rapid intensification of Bertha to Cat 3 - a fact that none of the forecasters predicted. The second dilemma had to do with the track forecast. These highly trained professionals rely to a large extent on computer model predictions as shown below for Bertha. From that, they generate the "official" track shown to the right. Earlier model runs showed Bertha curving to the north, but as time progressed, they continued to carry it in a more westerly direction, which began to get the attention of the public.
You can see from the picture of the model forecast tracks that there is some large disagreement among the dozen or so different models. Why such a large difference? Each model uses different parameters and different math to produce the tracks. Hence, the difference in the outcome. The forecasters usually rely on one or two models that they feel provides better guidance and then generate their own official track forecast. Once again, it can be seen in the figure above and as the black line buried in among the model runs shown above. (By the way, you may click on any of these figures to get an expanded look. To go back to the blog, just hit your browser back button.)
You can see from the picture of the model forecast tracks that there is some large disagreement among the dozen or so different models. Why such a large difference? Each model uses different parameters and different math to produce the tracks. Hence, the difference in the outcome. The forecasters usually rely on one or two models that they feel provides better guidance and then generate their own official track forecast. Once again, it can be seen in the figure above and as the black line buried in among the model runs shown above. (By the way, you may click on any of these figures to get an expanded look. To go back to the blog, just hit your browser back button.)Today, 11 July, BErtha is still with us as a weak Cat 1 storm located east of Bermuda. It does not pose a threat to the U.S. mainland at this time but probably will have some impact on the island of Bermuda. An interesting fact about Bertha is that it formed in the eastern Atlantic so early in the season. Normally this does not occur until mid to late August. The last time this happened was 2005, and we can all remember what occurred that year. This is not a prediction, - just a fact to keep in mind.
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