Tag: Francisco 2020

Feb. 14, 2020 – NASA Catches the Re-birth of Zombie Tropical Cyclone Francisco

The low-pressure area that had once been Tropical Cyclone Francisco has been lingering in the Southern Indian Ocean since Feb. 6 when it weakened below tropical cyclone status. Since then, Francisco’s remnants moved into an area of warm waters and low wind shear allowing the low-pressure area to re-organize, consolidate and re-form. NASA’s Aqua satellite provided forecasters with a visible image of the zombie storm.

On Feb. 14, the Moderate Resolution Imaging Spectroradiometer or MODIS instrument that flies aboard NASA’s Aqua satellite provided a visible image that showed the storm had re-developed a rounded shape with bands of thunderstorms spiraling into the low-level center. A more rounded shape of a tropical cyclone indicates it is becoming a more organized storm. Satellite imagery shows a compact system with strong thunderstorms persisting over the low-level circulation. In addition, satellite microwave imagery indicates deep convective banding of thunderstorms over the western semicircle wrapping into the north and east quadrants of a defined low-level circulation center.

On Feb. 14 at 4 a.m. EST (0900 UTC), the Joint Typhoon Warning Center (JTWC) noted that Francisco’s maximum sustained winds powered back up to 40 knots (46 mph/74 kph). Francisco re-formed near latitude 19.0 degrees south and longitude 49.3 east, approximately 114 nautical miles east of Antananarivo, Madagascar. Francisco has tracked southwestward.

Meteo Madagascar issued a Red Vigilance Advisory for heavy rain over central and eastern Madagascar that includes Toamasina, Brickaville, Mahanoro, and the Vatomandry Districts.

The JTWC forecast said the system is expected to make landfall later today over the southeast coast of Atsinanana Region, close to Vatomandry City. That is far to the south of the coastal city of Toamasina. Francisco is expected to weaken steadily as it tracks inland and dissipate sometime on Feb. 15 over land.

NASA’s Aqua satellite is one in a fleet of NASA satellites that provide data for hurricane research.

Tropical cyclones/hurricanes are the most powerful weather events on Earth. NASA’s expertise in space and scientific exploration contributes to essential services provided to the American people by other federal agencies, such as hurricane weather forecasting.

For updated forecasts from Meteo Madagascar, visit:  http://www.meteomadagascar.mg/

By Rob Gutro
NASA’s Goddard Space Flight Center

Feb. 06, 2020 – NASA Satellite Finds Wind Shear Adversely Affecting Tropical Storm Francisco

Forecasters use a variety of satellite imagery to understand what is happening in a storm, and sometimes just a visible picture can tell a lot. NASA-NOAA’s Suomi NPP satellite provided forecasters with a visible image of the Tropical Storm Francisco in the Southern Indian Ocean that showed wind shear was pushing clouds away from the storm’s center.

Visible imagery from satellites helps forecasters understand if a storm is organizing or weakening, or if it is being affected by vertical wind shear. The shape of a tropical cyclone provides forecasters with an idea of its organization and strength. When outside winds, that is, vertical wind shear, batter a storm it can change the shape of it and push much of the associated clouds and rains to one side of it.

In general, wind shear is a measure of how the speed and direction of winds change with altitude. Tropical cyclones are like rotating cylinders of winds. Each level needs to be stacked on top each other vertically in order for the storm to maintain strength or intensify. Wind shear occurs when winds at different levels of the atmosphere push against the rotating cylinder of winds, weakening the rotation by pushing it apart at different levels.

The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard Suomi NPP provided a visible image of Francisco on Feb. 6. The image showed vertical wind shear is displacing the deep convection about 125 nautical miles to the southeast. In addition, multispectral satellite imagery revealed that the low-level circulation center appeared elongated. When the circulation is not circular and appears elongated, it cannot spin as quickly, just like a tire. Thus, the storm weakens. Wind shear is causing the elongation and weakening the storm.

At 4 a.m. EDT (0900 UTC), the Joint Typhoon Warning Center (JTWC) issued their final advisory on Tropical Cyclone Francisco. At that time, Francisco was located near latitude 19.1 degrees south and longitude 71.7 degrees east, about 816 nautical miles east of Port Louis, Mauritius and moving southeast. Maximum sustained winds were near 35 knots (40 mph/65 kph) and weakening.

The JTWC expects Francisco will continue moving to the southeast until it dissipates.

Tropical cyclones/hurricanes are the most powerful weather events on Earth. NASA’s expertise in space and scientific exploration contributes to essential services provided to the American people by other federal agencies, such as hurricane weather forecasting.

By Rob Gutro 
NASA’s Goddard Space Flight Center

Feb. 05, 2020 – NASA Satellite Observes Tropical Storm Francisco’s Formation

Shortly after Tropical Cyclone Francisco formed on Feb. 5 in the Southern Indian Ocean, NASA’s Aqua satellite provided a visible image of the storm.

On Feb. 5, 2020, the Moderate Resolution Imaging Spectroradiometer or MODIS instrument that flies aboard NASA’s Aqua satellite provided a visible image of Francisco that showed powerful thunderstorms around the low-level center. Satellite imagery showed shallow thunderstorm banding wrapping into the center of the low-level center and strong convective bands of thunderstorms over the eastern semicircle.

On Feb. 5 at 4 a.m. EST (0900 UTC), the Joint Typhoon Warning Center (JTWC) noted that Tropical Cyclone Francisco was located near latitude 17.3 degrees south and longitude 68.5 degrees east, about 647 nautical miles east-southeast of Mauritius. Maximum sustained winds 40 knots (46 mph/74 kph). This storm is moving to the southeastward.

Francisco is forecast to slightly intensify today, Feb. 5. The JTWC expects Francisco will continue to track southeast to south over the next day and a half and turn to the west-southwest after which time it is expected to begin weakening.

NASA’s Aqua satellite is one in a fleet of NASA satellites that provide data for hurricane research.

Tropical cyclones/hurricanes are the most powerful weather events on Earth. NASA’s expertise in space and scientific exploration contributes to essential services provided to the American people by other federal agencies, such as hurricane weather forecasting.

By Rob Gutro
NASA’s Goddard Space Flight Center