Why such a slow start to the hurricane season?
It was predicted to be an above average year but so far there has been only one hurricane and a few depressions/storms. Also, the waters are supposed to be really warm and LA NINA is developing. All this should be great for hurricane formation. Why such a slow start?
Tagged with: depressions • hurricane formation • la nina • storms
Filed under: Hurricane Questions
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I’ve doubted the pre-season forecasts of ±20 named storms since their issuance, and as the season progresses, I think it’s clear the 2010 season won’t compare to more active seasons like 2005 and 1998 as suggested this spring. To achieve 20 named storms, we would need abnormally high activity in all three segments of the hurricane season; early-season, mid-season, and late-season, and, Hurricane Alex notwithstanding, the early-season this year has proven relatively benign. Conditions over the Atlantic have been rather hostile for tropical cyclone formation and sustenance over the past couple months, in some cases to the surprise of hurricane specialists and forecasters.
I’ll freely admit that I think the 2010 Atlantic hurricane season forecasts will bust. And that’s to be expected when dealing with such a sensitive and ever-changing branch of science as meteorology. However, we should by no means let our guard down. It only takes one or two storms to establish a season in the record books, as evidenced by 1992 – if not for the catastrophic Hurricane Andrew, that season would be known as one of the most insignificant in recent memory. Aside from Andrew, only one other storm made landfall.
Additionally, tropical cyclone activity in the Atlantic usually picks up toward the middle of August, when a number of factors converge to create more conducive conditions for tropical development. Among them are a decrease in dry air and an increase in the vigor of tropical waves (elongated areas of low pressure) emerging from the African coast. Several dozen of these waves develop each year, and during the peak of hurricane season, they’ll occasionally begin to spin up as they move westward, eventually maturing into intense hurricanes.
It’s wise to keep an eye on the National Hurricane Center’s website (http://www.nhc.noaa.gov/) for the next couple months, so you’ll be informed of any disturbances or storms in the Atlantic. Tropical cyclones in this basin almost exclusively move westward in the beginning of their lives, so the United States is ever-vulnerable to landfalls or near-misses. It’s probable at least a couple more storms will make landfall, causing some degree of damage. Keep in mind that the end number of storms is not nearly as important as the number of storms to affect land or the number of storms to cause significant damage. If we discount minor depressions and storms that barely managed to limp across land, we’re left with only one storm so far. However, that storm (Alex) caused billions of dollars in damage, and is a candidate for retirement next spring.
The wind shear environment has made it difficult for tropical systems from forming. If they did form, the shear has kept them relatively weak. The current thinking among the tropical storm experts is that with the rapid development of the La Nina will decrease the shear environment and will make conditions more favorable to tropical development for the second half of the season.
Even though the sea surface temperature was not as warm as what the experts had expected, it is still warm enough to support development. So if the tmosphere can lose some of the shear, things can quickly chane in a heart beat. Whether this will really happen is still the big question.
The condition just haven’t been favorable for development. The Saharan Dust cloud has helped to keep the water temperature down some (this is now starting to abate), as has the solar minimum. The few that have formed have had short life spans wind shear, and in the case of the last two storms (Colin and TD 5), also due to entraining dry air, and being near an upper level low pressure system (tropical cyclones need an over head high to develop and sustain themselves).
Yeah it is a slow season but some scientist and meteorologists say the season is going to be as active as 2005 when Hurricane Katrina made landfall!