What meteorologists search for in early signs of a future hurricane

When tropical meteorologists Satellite imagesthey often see subtle cloud formations that indicate that something more sinister is brewing.

The first signs of a possible hurricane could be detected days before the storm develops. Thin, outward-radiating cirrus clouds, the looks of low-lying clouds with curved bands, and a drop in barometric pressure are all indicators.

These early clues are crucial for predicting the onset of a potentially catastrophic hurricane.

I’m a Professor of Meteorology at Penn State and my research group are using satellites and computer models to enhance the forecasting of tropical weather systems. With a very severe storm season forecast for the Atlantic in 2024, it’s more necessary than ever to have the option to acknowledge these early signals and supply early warning. Here's what meteorologists are searching for.

Hurricane Harvey entered the Gulf of Mexico as a tropical wave before becoming a tropical storm after which a destructive hurricane that struck Texas in 2017. NOAA.

Conditions for a hurricane

Hurricanes typically begin as atmospheric tropical wavesLow pressure areas related to clusters of thunderstorms. As these tropical waves move westward over the tropical oceans, a few of them can grow to be hurricanes.

The formation of a hurricane will depend on several specific conditions:

Distance from the equator: Tropical cyclones normally form at the least 5 degrees from the equator. This is since the Coriolis forcewhich is crucial for the initial rotation of the cyclone system, is weaker near the equator. The Coriolis force is attributable to the rotation of the earth, which causes moving air to rotate and swirl.

Warm sea surface temperatures: The sea surface temperature must at the least 26.5 degrees Celsius (approx. 80 Fahrenheit) for the formation of a hurricane. The warm water provides energy that drives the storm because the storm absorbs heat and moisture from the ocean.

Atmospheric instability and humidity: For tropical cyclones to form, the atmosphere have to be unstable. This signifies that warm surface air rises and stays warmer than the encircling air, allowing it to proceed to rise and form thunderstorms. There must even be quite a lot of moisture, as dry air can evaporate clouds and weaken the upward motion in thunderstorms. These aspects are essential for the event of thunderstorm clusters throughout the tropical waves.

Low vertical wind shear: Strong vertical wind shear can tear apart a developing hurricane. Vertical wind shear is a change in wind direction or speed at different altitudes. It disrupts the formation and growth of a storm and makes it difficult for a hurricane to maintain its vortex aligned.

Early predictions require greater than satellites

Detecting the early stages in a hurricane's life cycle may be very difficult because there will not be many surface stations and weather balloons that might provide detailed atmospheric information over the open ocean.

Once a storm forms, the National Oceanic and Atmospheric Administration's hurricane-hunting planes often fly through it, taking measurements and dropping sensors to get more data. But that's impossible for each thin cloud, especially if the developing system is way from the coast.

One of a very powerful tools meteorologists currently use to predict the early formation of hurricanes is satellite imagery, which provides real-time data on cloud patterns, sea surface temperatures, and other atmospheric conditions. GOES satellites The satellites operated by NOAA help meteorologists track the event of hurricanes with unprecedented clarity. These satellites can capture images at multiple wavelengths, allowing meteorologists to investigate different points of the storm, corresponding to Cloud formation, precipitation And Lightning activity.

Four images show different stages of Hurricane Irma's formation, from a disorganized collection of storms to a single hurricane.
The formation of Hurricane Irma in 2017, from a disturbance to a hurricane with a transparent vortex, observed by satellite. The colours show the temperature of the cloud top. Lower temperatures mean the cloud is deeper. The streamlines show the circulation of the system.
European Space Agency, Meteosat-10

However, satellite observations alone don’t provide meteorologists with enough information to predict which tropical waves are more likely to grow to be hurricanes.

To improve forecast accuracy, our research group has developed Methods for integrating real-time satellite dataincluding humidity and cloud patterns, into computer forecast models. This process, referred to as data assimilation, enables a more accurate and consistent representation of atmospheric conditions. This allows meteorologists to learn from significantly improved forecasting capabilities, especially in predicting the formation and path of hurricanes.

We are currently Collaboration with NOAA These techniques will likely be refined and used on a bigger scale to enhance hurricane forecasts and supply earlier warnings in order that the population has more time to arrange.

As people in North America and the Caribbean prepare for what is predicted to be a very intense hurricane season in 2024, the necessity for accurate early storm forecasts is larger than ever.

image credit : theconversation.com