Category Archives: Tropical
Forming over tropical oceans ensures that warm sea-surface temperature (SST) provides a mature hurricane with a means to warm and moisten the air that flows toward the important eye-wall convection. Thus, it is not surprising that hurricanes struggle to develop if the SST is not 79.7 degrees F or warmer. Tropical cyclones also require environments in which the wind speed and direction changes very little with increasing height, in other words, where the vertical wind shear is small. Continue reading
The organized storms we experience here in Madison in fall and winter are known as mid-latitude cyclones. One of the most notable characteristics of these storms is the presence of strong temperature, humidity and wind contrasts at what are known as fronts. In fact, fronts are such an integral part of the structure of these storms that they are often referred to as frontal cyclones. Continue reading
Hurricane season runs from June 1 through Nov. 30. The National Oceanic and Atmospheric Administration has been making seasonal forecasts for about the last decade. Their Atlantic Hurricane Season Outlook for this year indicates there is a 70 percent likelihood of having 13 to 20 named storms, of which seven to 11 could become hurricanes, including three to six major hurricanes. Continue reading
Nearly a week after Hurricane Sandy struck the Mid-Atlantic coast of the United States, the affected region is still reeling from the shock. This really was an unprecedented storm in the truest sense of that word.
Among the amazing aspects of the event was the extraordinarily accurate and early forecasting of the storm. Numerical forecast models were latching on to the correct scenario, including the unusual and rapid leftward turn off the Mid-Atlantic coast, as early as five to seven days before the event (depending on the particular model in question). Continue reading
Hurricanes are large weather engines, and any engine needs energy to run.
The secret energy source of a hurricane is the large latent heat of water. Air over the tropical oceans is drier than you might think. Although both the air and water may be warm and calm, evaporation can take place because the air is not at 100 percent relative humidity. Continue reading