NASA - EOS Terra Mission patch / NOAA & NASA - Suomi NPP Mission patch.
August 25, 2020
Laura – Atlantic Ocean
Aug. 25, 2020 – NASA Gathers Nighttime Images of Laura Becoming a Hurricane
Tropical Storm Laura strengthened to a hurricane in the morning hours of Aug. 25, and NASA provided infrared imagery that showed the structure, temperature and rainmaking capabilities of the storm. When NASA’s Terra satellite and NASA-NOAA’s Suomi NPP satellite passed overhead, both provided different images of Laura as it was about to exit the Caribbean Sea and move into the Gulf of Mexico.
Image above: On Aug. 25 at 12:35 a.m. EDT (0435 UTC) the MODIS instrument that flies aboard NASA’s Terra satellite revealed the most powerful thunderstorms (yellow) were around Laura’s center where cloud top temperatures were as cold as minus 80 degrees Fahrenheit (minus 62.2 Celsius). Those storms were over the Caribbean Sea, just south of western Cuba. Strong storms (red) with cloud top temperatures as cold as minus 70 degrees Fahrenheit (minus 56.6. degrees Celsius) surrounded the center and were generating large amounts of rain. Image Credits: NASA/NRL.
Watches and Warnings on Aug. 25
On Aug. 25, NOAA’s National Hurricane Center (NHC) posted several watches and warnings.
A Storm Surge Warning is in effect from San Luis Pass Texas to the mouth of the Mississippi River, including areas inside the Port Arthur Hurricane Flood Protection system. A Hurricane Warning is in effect from San Luis Pass, Texas to Intracoastal City, Louisiana.
A Tropical Storm Warning is in effect from Sargent, Texas to San Luis Pass and from east of Intracoastal City to the mouth of the Mississippi River. A Storm Surge Watch is in effect from Freeport, Texas to San Luis Pass.
NASA’s Night-Time View of Laura’s Intensification
Image above: NASA-NOAA’s Suomi NPP satellite passed the Caribbean Sea early on Aug. 25 and captured a nighttime image of Tropical Storm Laura. Not yet named a hurricane, the development of an eye was apparent. Image Credits: NASA Worldview, Earth Observing System Data and Information System (EOSDIS).
The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard Suomi NPP provided a nighttime image of Laura during the early morning hours of Aug. 25. Not yet named a hurricane, the development of an eye was apparent. By 11 a.m. EDT, Laura had a central dense overcast and some outer banding in the southern quadrant.
Satellite imagery shows the storm is over 350 miles in diameter. Hurricane-force winds extend outward up to 45 miles (75 km) from the center and tropical-storm-force winds extend outward up to 175 miles (280 km).
NASA’s Infrared Data Reveals Heavy Rainmakers
Tropical cyclones are made up of hundreds of thunderstorms, and infrared data can show where the strongest storms are located. That is because infrared data provides temperature information, and the strongest thunderstorms that reach highest into the atmosphere have the coldest cloud top temperatures.
On July 27 at 4:35 a.m. EDT (0835 UTC), the Moderate Resolution Imaging Spectroradiometer or MODIS instrument that flies aboard NASA’s Aqua satellite used infrared light to analyze the strength of storms within Laura. MODIS found the most powerful thunderstorms were around Laura’s center over the Caribbean Sea, just south of western Cuba, where cloud top temperatures were as cold as minus 80 degrees Fahrenheit (minus 62.2 Celsius). NASA research has found that cloud top temperatures that cold indicate strong storms with the potential to generate heavy rainfall.
Strong storms with cloud top temperatures as cold as minus 70 degrees Fahrenheit (minus 56.6. degrees Celsius) circled the most powerful storms, and were also dropping large amounts of rain.
Animation above: NASA-NOAA’s Suomi NPP satellite provided visible imagery of Tropical Storm Laura’s movement in the Atlantic Ocean from Aug. 21 to 24. It affected the Northern Leeward Islands, Puerto Rico, Hispaniola, Jamaica and Cuba before moving into the Gulf of Mexico on Aug. 25. Animation Credits: NASA Worldview, Earth Observing System Data and Information System (EOSDIS).
Laura’s Status on Aug. 25, 2020
At 11 a.m. EDT (1500 UTC), the center of Hurricane Laura was located near latitude 23.7 degrees north and longitude 87.0 degrees west. That is about 585 miles (940 km) southeast of Lake Charles, Louisiana and about 620 miles (1,000 km) southeast of Galveston, Texas.
Laura was moving toward the west-northwest near 16 mph (26 kph), and this general motion should continue today, according to NHC. A turn toward the northwest is forecast by Wednesday, and a northwestward to north-northwestward motion should continue through Wednesday night. Reports from NOAA and Air Force Reserve Hurricane Hunter aircraft indicate that maximum sustained winds are near 75 mph (120 kph) with higher gusts. The estimated minimum central pressure based on the Hurricane Hunter aircraft data is 990 millibars.
Laura’s Forecast from NHC
Significant strengthening is forecast during the next 36 hours, and Laura is expected to be a major hurricane at landfall. NHC noted the forecast calls for the hurricane to make landfall in the area of southwestern Louisiana or the upper Texas coast late Wednesday night or Thursday morning.
About NASA’s EOSDIS Worldview
NASA’s Earth Observing System Data and Information System (EOSDIS) Worldview application provides the capability to interactively browse over 700 global, full-resolution satellite imagery layers and then download the underlying data. Many of the available imagery layers are updated within three hours of observation, essentially showing the entire Earth as it looks “right now.”
NASA Researches Earth from Space
For more than five decades, NASA has used the vantage point of space to understand and explore our home planet, improve lives and safeguard our future. NASA brings together technology, science, and unique global Earth observations to provide societal benefits and strengthen our nation. Advancing knowledge of our home planet contributes directly to America’s leadership in space and scientific exploration.
For updated forecasts, visit: http://www.nhc.noaa.gov/
NASA’s Terra satellite: http://www.nasa.gov/mission_pages/terra/index.html
Text, Credits: NASA/Lynn Jenner/Goddard Space Flight Center, by Rob Gutro.
Marco (was TD14) – Atlantic Ocean
Aug. 25, 2020 – NASA’s Terra Satellite Catches the Demise of Post-Tropical Cyclone Marco
NASA’s Terra satellite passed over the Gulf of Mexico early on Aug. 25 and found a very small area of convection from post-tropical cyclone Marco, northeast of its center. All watches and warnings have been dropped as the storm continues to weaken toward dissipation.
Image above: On Aug. 25 at 12:30 a.m. EDT (0430 UTC), the MODIS instrument that flies aboard NASA’s Terra satellite gathered infrared data on post-tropical cyclone Marco that showed a small area of storms where cloud top temperatures were as cold as minus 50 degrees Fahrenheit (minus 45.5 Celsius). Image Credits: NASA/NRL.
Visible imagery and surface observations indicated that Marco made landfall around 7 p.m. EDT on Aug. 24 near the mouth of the Mississippi River. The center continued to move west and moved offshore and south of Louisiana by Aug. 25.
NASA’s Terra Satellite Reveals Effects of Wind Shear
NASA’s Terra satellite uses infrared light to analyze the strength of storms by providing temperature information about the system’s clouds. The strongest thunderstorms that reach high into the atmosphere have the coldest cloud top temperatures.
On Aug. 25 at 12:30 a.m. EDT (0430 UTC), the Moderate Resolution Imaging Spectroradiometer or MODIS instrument that flies aboard NASA’s Terra satellite observed Marco in infrared light and found a small area of storms where cloud top temperatures as cold as minus 50 degrees Fahrenheit (minus 45.5 Celsius) over the western Florida Panhandle and coastal Alabama. Those storms were being pushed northeast of Marco’s center from southwesterly wind shear. Satellite imagery also shows the low-level circulation center was a swirl of clouds south of Louisiana, over the Gulf of Mexico.
NASA’s EOS Terra satellite. Image Credit: NASA
In the Aug. 25, Marco discussion at 5 a.m. EDT, NHC Senior Hurricane Specialist Stacy Stewart noted, “Marco has been devoid of any significant convection for at least 12 hours. [NOAA’s Advanced Scatterometer] ASCAT scatterometer surface wind data around 0239Z (10:39 p.m. EDT on Aug. 24) suggested that Marco might have degenerated in a north-to-south elongated trough (elongated area of low pressure). Based on this information, Marco has been downgraded to post-tropical remnant low [pressure area].”
About Wind Shear
The shape of a tropical cyclone provides forecasters with an idea of its organization and strength. When outside winds batter a storm, it can change the storm’s shape and push much of the associated clouds and rain to one side of it. That is what wind shear does.
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.
Marco’s Final Status
At 5 a.m. EDT (0900 UTC) on Aug. 25, NOAA’s National Hurricane Center (NHC) reported the center of Post-Tropical Cyclone Marco was located near latitude 28.8 degrees north and longitude 91.2 degrees west. That is about 60 miles (100 km) south of Morgan City, La. and 110 miles (175 km) south-southeast of Lafayette, La. The post-tropical cyclone was moving toward the west near 10 mph (17 kph), and this general motion is expected to continue for the next day or so. Maximum sustained winds were near 30 mph (45 kph) with higher gusts. The estimated minimum central pressure was 1008.
Marco Nears its End
Brisk southwesterly vertical wind shear of 30 knots is forecast to increase to near 35 knots in 24 hours, which should prevent the redevelopment of deep convection near the center. On the forecast track, Marco should continue moving westward just offshore the coast of Louisiana until the system dissipates.
NASA Researches Tropical Cyclones
Hurricanes/tropical cyclones 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 more than five decades, NASA has used the vantage point of space to understand and explore our home planet, improve lives and safeguard our future. NASA brings together technology, science, and unique global Earth observations to provide societal benefits and strengthen our nation. Advancing knowledge of our home planet contributes directly to America’s leadership in space and scientific exploration.
Related article:
Hurricanes Laura & Marco – Atlantic Ocean
https://orbiterchspacenews.blogspot.com/2020/08/hurricanes-laura-marco-atlantic-ocean.html
Related links:
NASA-NOAA’s Suomi NPP satellite: http://www.nasa.gov/mission_pages/NPP/main/index.html
For updated forecasts. visit: http://www.nhc.noaa.gov/
Text, Credits: NASA/Lynn Jenner/Goddard Space Flight Center, by Rob Gutro.
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