Oct. 11, 2019 – NASA Sees Atlantic Subtropical Storm Melissa Form off New England Coast
Satellite data has confirmed the formation of Subtropical Storm Melissa. NASA’s Terra Satellite provided a visible image the former Nor’easter turned subtropical storm off the coast of New England.
The National Hurricane Center or NHC noted that the Nor’easter centered southeast of New England (in the northeastern U.S.) becomes a subtropical storm, and that the change in storm status does not change expected impacts from wind and coastal flooding along portions of the mid-Atlantic coast and Southeastern New England.
On Oct. 11, the Moderate Imaging Spectroradiometer or MODIS instrument that flies aboard NASA’s Terra satellite provided a visible image of the newly developed Melissa. Forecasters at the National Hurricane Center noted on Oct.11 at 11 a.m. EDT, “Convection increased near the center of the nor’easter centered southeast of New England overnight. First-light visible satellite imagery briefly showed an eye-like feature before the convection around the immediate center began to weaken. However, a large convective band still persists over the northern semicircle, and this structure indicated the system has transitioned to a subtropical cyclone.”
On Oct. 11, the MODIS instrument that flies aboard NASA’s Terra provided a visible image of Subtropical Storm Melissa off the New England coast. Credit: NASA Worldview, Earth Observing System Data and Information System (EOSDIS).
At 11 a.m. EDT (1500 UTC), on Oct. 11, the center of Subtropical Storm Melissa was located near latitude 38.5 degrees North and longitude degrees 69.6 West. That is about 190 miles (300 km) south of Nantucket, Massachusetts. Melissa is moving toward the south-southwest near 3 mph (6 kph), but little net motion is expected today. A turn toward the east-northeast with an increase in forward speed is forecast tonight and this motion will continue through the weekend. On the forecast track, the center of Melissa will move away from the east coast of the United States.
Maximum sustained winds are near 65 mph (100 kph) with higher gusts. Gradual weakening is expected over the next couple of days, and Melissa is forecast to lose its subtropical characteristics by Saturday night. Winds of 40 mph extend outward up to 345 miles (555 km) from the center, primarily over waters. The estimated minimum central pressure is 995 millibars.
Hurricanes are the most powerful weather event 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.
Oct. 11, 2019 – Suomi NPP Satellite Finds a Weaker Typhoon Hagibis Nearing Japan
On Oct. 10, Hagibis was a super typhoon, but overnight, the storm weakened to typhoon status. NASA-NOAA’s Suomi NPP satellite provided a visible image of the large storm that stretched along most of the big islands of Japan.
Visible imagery from NASA satellites help forecasters understand if a storm is organizing or weakening, based on changes to its structure. The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard Suomi NPP provided a visible image of Hagibis that showed the eye had become cloud-filled. Despite that, A solid ring of deep convection (strong thunderstorm development) is evident around the compact, 10 nautical mile wide eye.
NASA-NOAA’s Suomi NPP satellite passed over Typhoon Hagibis and revealed the eye had become cloud-filled as the storm weakened from a super typhoon to a typhoon. The eye was surrounded by powerful thunderstorms and a large tail of clouds that covered most of Japan. Credit: NASA Worldview, Earth Observing System Data and Information System (EOSDIS)
The image was created using NASA Worldview, the Earth Observing System Data and Information System (EOSDIS) data product at NASA’s Goddard Space Flight Center in Greenbelt, Md. The image showed the cloud-filled eye circled by powerful thunderstorms and a large tail of clouds streaming to the northeast of the center that stretched along much of Japan’s east coast.
At 5 a.m. EDT (0900 UTC), the Joint Typhoon Warning Center reported the center of Typhoon Hagibis was located near latitude 28.8 degrees north and longitude 137.5 degrees east. Hagibis is about 406 nautical miles south of Yokosuka, Japan. Hagibis was moving toward the north-northwest. Maximum sustained winds are near 132 mph (213 kph/115 knots) with higher gusts. It is the equivalent of a Category 3 hurricane on the Saffir-Simpson hurricane wind scale.
The Joint Typhoon Warning Center noted that Hagibis has continued to weaken and will turn to the northeast on approach to Honshu. Hagibis is expected to make a brief landfall near Tokyo during Saturday (GMT) before curving back out into the Northwestern Pacific Ocean. The system is forecast to become extra-tropical south of the Kuril Islands on Sunday.
Hurricanes are the most powerful weather event 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.
Oct. 10, 2019 – NASA-NOAA’s Suomi NPP Satellite Needed 3 Orbits to See All of Super Typhoon Hagibis
NASA-NOAA’s Suomi NPP satellite provided forecasters with a composite visible image of the very large Super Typhoon Hagibis in the Northwestern Pacific Ocean on Oct. 10. It took Suomi NPP three orbits to capture images to show the entire storm that revealed it maintained its impressive structure.
Visible imagery from NASA satellites help forecasters understand if a storm is organizing or weakening, based on changes to its structure. The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard Suomi NPP provided three visible images of Hagibis on Oct. 10. Those images had to be stitched together to show the entire storm on NASA Worldview, the Earth Observing System Data and Information System (EOSDIS) data product at NASA’s Goddard Space Flight Center in Greenbelt, Md. The image showed an eye surrounded by powerful thunderstorms and a large “tail” of clouds streaming to the northeast of the center.
NASA-NOAA’s Suomi NPP satellite passed over Super Typhoon Hagibis and revealed the storm maintaining an eye surrounded by powerful thunderstorms, and a large “tail” of clouds streaming to the northeast of the center. Credit: NASA Worldview, Earth Observing System Data and Information System (EOSDIS)
At 5 a.m. EDT (0900 UTC), NHC reported the center of Super Typhoon Hagibis was located near latitude 24.4 degrees north and longitude139.4 degrees east. Hagibis is about 654 miles (560 km) south of Yokosuka, Japan. Hagibis is moving toward the north-northwest. Maximum sustained winds are near 161 mph (259 kph/140 knots) with higher gusts.
Hagibis remains at peak intensity as a Category 5 hurricane on the Saffir-Simpson Hurricane Wind Scale. The system will continue north-northwest as it goes through a weakening trend on approach to Japan. The Joint Typhoon Warning Center noted, “Hagibis will be making a quick landfall near Yokosuka via Sagami wan shortly after 48 hours (after 5 a.m. EDT (0900 UTC) on Oct. 10) before exiting back into the Pacific Ocean.”
Hurricanes are the most powerful weather event 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.
Oct. 9, 2019 – NASA Covers Super Typhoon Hagibis Day and Night
NASA-NOAA’s Suomi NPP satellite provided daytime and nighttime imagery of powerful Super Typhoon Hagibis, revealing a small eye surrounded by powerful thunderstorms as the storm maintained strength.
Visible imagery from NASA satellites help forecasters understand if a storm is organizing or weakening. The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard Suomi NPP provided an infrared image of Hagibis on Oct. 8 at 11:56 a.m. EDT (1556 UTC) and a visible image of Hagibis on Oct. 9.
NASA-NOAA’s Suomi NPP satellite was able to catch a nighttime view of Hagibis around 11:56 a.m. EDT (1556 UTC) on Oct 8. The waxing gibbous Moon (76% illumination) was just setting providing ample lighting to see the small cloud filled eye along with lightning streaks and some tropospheric gravity waves. Credit: NASA/NOAA/UWM CIMSS, William Straka III.
The night-time high resolution infrared imagery showed a very small eye along with copious amounts of tropospheric gravity waves as well as some overshooting cloud tops (into the stratosphere) in some of the outer bands of thunderstorms. Overshooting cloud tops indicate very strong uplift of air and powerful thunderstorms. The waxing gibbous Moon (76% illumination) was just setting and provided ample lighting to see the small cloud-filled eye along with lightning streaks and some tropospheric gravity waves.
It took two images stitched together to create a complete visible, daytime picture of Hagibis. The Suomi NPP satellite passed over Hagibis twice on October 9 to get the entire storm. That image revealed that Hagibis maintained its small eye and powerful thunderstorms circling the center. Powerful bands of thunderstorms from north and south of center were also spiraling into the low-level center. The image was created by NASA Worldview, Earth Observing System Data and Information System (EOSDIS) at NASA’s Goddard Space Flight Center in Greenbelt, Md.
On Oct. 9, 2019, NASA-NOAA’s Suomi NPP satellite passed over Super typhoon Hagibis and captured this visible image of the storm. Credit: NASA Worldview, Earth Observing System Data and Information System (EOSDIS)
On Oct. 9 at 11 a.m. EDT (1500 UTC), Hagibis was centered near 21.2 degrees north latitude and 139.6 degrees east longitude. That is about 236 nautical miles south-southwest of Iwo To island, Japan. Hagibis was moving to the north-northwest at 6 knots and had maximum sustained winds near 140 knots (161 mph/259 kph) making it a Category 5 hurricane on the Saffir-Simpson hurricane wind scale.
Hagibis is expected to remain a strong tropical cyclone over the next day, eventually weakening as it turns to the north and likely impacting Japan by the weekend, per the Joint Typhoon Warning Center.
Hurricanes are the most powerful weather event 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.
Sept. 7, 2019 – Update #3 – NASA Finds Dorian Transitioning to an Extra-Tropical Cyclone
NASA satellites provided forecasters at the National Hurricane Center with infrared data and cloud top temperature information for Hurricane Dorian. Infrared data revealed that Dorian was becoming an extra-tropical cyclone as it moved northeast along the U.S. east coast and the area of strong storms had diminished around the storm.
NASA researches tropical cyclones and infrared data is one of the ways NASA uses. Cloud top temperatures provide information to forecasters about where the strongest storms are located within a tropical cyclone. The stronger the storms, the higher they extend into the troposphere, and they have the colder cloud temperatures.
On Sept. 6, at 2:23 p.m. EDT (1823 UTC), NASA’s Aqua satellite analyzed the storm using the Atmospheric Infrared Sounder or AIRS instrument. AIRS found coldest cloud top temperatures as cold as or colder than minus 80 degrees Fahrenheit (minus 62.2 degrees Celsius) circling around the center (eye) and in a thick band of thunderstorms northeast of the center. NASA research has shown that cloud top temperatures that cold indicate strong storms that have the capability to create heavy rain.
On Sept. 6, at 2:23 p.m. EDT (1823 UTC) the AIRS instrument aboard NASA’s Aqua satellite analyzed cloud top temperatures of Hurricane Dorian in infrared light. AIRS found coldest cloud top temperatures (purple) of strongest thunderstorms were as cold as or colder than minus 80 degrees Fahrenheit (minus 62.2 degrees Celsius) around the center and in a thick band of thunderstorms northeast of the center. Credit: NASA JPL/Heidar Thrastarson
On Sept. 7 at 3 a.m. EDT (0700 UTC), it was NASA-NOAA’s Suomi NPP satellite that provided an infrared view of Hurricane Dorian as it was transitioning into an extra-tropical storm. Strongest storms had cloud top temperatures as cold as or colder than minus 80 degrees Fahrenheit (minus 62.2 degrees Celsius) where the heaviest rain was falling over the open waters of the Atlantic Ocean. Those storms were now limited to the southern side of the storm, unlike the previous day, when they circled the eye.
NASA-NOAA’s Suomi NPP satellite provided an infrared view of Hurricane Dorian as it was transitioning into an extra-tropical storm on Sept. 7 at 3 a.m. EDT (0700 UTC). Strongest storms (red) had cloud top temperatures as cold as or colder than minus 80 degrees Fahrenheit (minus 62.2 degrees Celsius) where the heaviest rain was falling over the open waters of the Atlantic Ocean. Credit: NASA/NOAA/NRL
NOAA’s National Hurricane Center’s (NHC) discussion said “Satellite imagery this morning [Sept. 7] indicates that Dorian is starting extratropical transition, with cold air clouds entraining [moving] into the southwestern side of the cyclone and a developing warm front to the north and east.”
What is an Extra-Tropical Cyclone?
When a storm transitions into an extra-tropical cyclone, it means that a tropical cyclone has lost its tropical characteristics. The National Hurricane Center defines “extra-tropical” as a transition that implies both poleward displacement (meaning it moves toward the north or south pole) and the conversion of the cyclone’s primary energy source from the release of latent heat of condensation to baroclinic (the temperature contrast between warm and cold air masses) processes. It is important to note that cyclones can become extratropical and still retain winds of hurricane or tropical storm force.
Warnings and Watches in Effect on Sept. 7
NOAA’s National Hurricane Center’s (NHC) continued to issue warnings and watches as Dorian makes its way toward Canada today. A Hurricane Warning is in effect for eastern Nova Scotia from lower east Pubnico to Brule, and for western Newfoundland from Indian Harbour to Hawke’s Bay, Canada. A Hurricane Watch is in effect for Prince Edward Island and the Magdalen Islands.
A Tropical Storm Warning is in effect from east of Bar Harbor to Eastport, ME, and for Prince Edward Island, Canada. It is also in effect for southwestern Nova Scotia from Avonport to north of Lower East Pubnico, Fundy National Park to Shediac, Stone’s Cove to Indian Harbour, Hawke’s Bay to Fogo Island and from Mutton Bay to Mary’s Harbour, Canada.
Status of Hurricane Dorian on Saturday, September 7, 2019
On Saturday, September 7, 2019 at 11 a.m. EDT (1500 UTC), the center of Hurricane Dorian was located near latitude 42.0 degrees north and longitude 66.0 degrees west.
Dorian’s center is about 205 miles (330 km) south-southeast of Eastport, Maine and about 215 miles (350 km) southwest of Halifax, Nova Scotia, Canada.
The NHC said Dorian is moving toward the northeast near 29 mph (46 kph), and a general motion toward the northeast is expected to continue through Sunday night. Maximum sustained winds are near 85 mph (140 kph) with higher gusts. Dorian is expected to become a hurricane-force post-tropical cyclone as it moves across eastern Canada tonight or on Sunday, Sept. 8. The estimated minimum central pressure is 953 millibars.
What’s Next for Dorian?
Dorian is expected to finish transition into an extratropical cyclone over the next day as it merges with a strong mid- to upper-level trough (elongated area of low pressure) and its associated surface front.
On the NHC forecast track, the center of Dorian is expected to move across central or eastern Nova Scotia this afternoon or this evening, pass near or over Prince Edward Island tonight, and then move near or over portions of Newfoundland and Labrador on Sunday.
Sep. 07, 2019 – Update #2 – In the Wake of Hurricane Dorian
The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite acquired these natural-color images of Great Abaco Island and Grand Bahama on August 17, 2019. Credit: NASA
In the first week of September 2019, Hurricane Dorian left a path of destruction from the Caribbean to the Canadian Maritimes. Reaching category 5 strength for nearly two days and sustaining major hurricane status from August 30 to September 3, the storm devastated the northern Bahama Islands, strafed the southeast U.S. coast, and arrived in Nova Scotia as one of the five strongest hurricanes on record for that region.
The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite acquired these natural-color images of Great Abaco Island and Grand Bahama on September 7, 2019. Credit: NASA
The images above provide a broad view of the devastation in the northern Bahamas, which were lashed for nearly 40 hours by the second strongest Atlantic hurricane in modern meteorological records. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite acquired these natural-color images of Great Abaco Island and Grand Bahama on August 17 and September 7, 2019. Note the change in the color of the island landscape from green to brown, as well as the brightening of the reefs and shoals around the island due to sediments stirred up by the storm.
The widespread browning of Great Abaco and Grand Bahama could have several causes. Many trees were uprooted and destroyed by the storm, and some species of vegetation in the tropics have evolved to lose leaves and small branches in strong winds. The loss of leafy vegetation would give the satellite a view of more bare ground. Another possibility is that salt spray whipped up by the hurricane coated and desiccated some leaves while they were still on the trees.
Government officials from the Bahamas have reported at least 40 deaths, according to news accounts, though the number is expected to rise after search and rescue operations are complete. Hundreds of people are missing and an estimated 70,000 are homeless. Few areas have electric power or running water. National and international relief supplies are just beginning to arrive in the area, though transportation is difficult.
At the other end of the storm track, Dorian brought destructive winds and waves 1500 miles (2400 kilometers) to the north. After transitioning to an extra-tropical cyclone, the storm made landfall in Nova Scotia on the evening of September 7 at category 2 strength. Maximum wind speeds approached 100 miles (160 kilometers) per hour at the coast. According to Weather Underground, hurricane-force winds extended 115 miles (185 kilometers) from the center of the storm, and tropical storm-force winds extended 300 miles (500 kilometers).
The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite captured this natural-color image of the vast storm just after midday on September 7, 2019. Credit: NASA
According to news reports, Dorian knocked out power to more than 500,000 customers in the Canadian Maritime Provinces, including Nova Scotia. A near-record storm surge was observed in the harbor at Halifax and along the coast of New Brunswick. And according to preliminary weather data, an offshore weather buoy measured a peak wave height of 30.7 meters (100.7 feet) in the open ocean.
Sep. 07, 2019 – Update #1 – NASA Images Temperature of Hurricane Dorian from Space Station
NASA’s ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) has imaged the temperature of Hurricane Dorian from the International Space Station. ECOSTRESS provides NASA’s highest resolution temperature measurement from space, and is able to map fine detail in temperature patterns from the hurricane. The patterns reveal the small cloud structures that contribute to the formation of the larger hurricane.
NASA’s ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) has imaged the temperature of Hurricane Dorian from the International Space Station. ECOSTRESS provides NASA’s highest resolution temperature measurement from space, and is able to map fine detail in temperature patterns from the hurricane. The patterns reveal the small cloud structures that contribute to the formation of the larger hurricane. Credit: NASA JPL
The image shows Hurricane Dorian on September 6, 2019 at 5:43 a.m. EDT, as it made landfall in North Carolina. Red colors are hotter temperatures, and purple/blue colors are cooler temperatures. The width of the color image is based on what ECOSTRESS sees as the Space Station flies over any given spot on Earth.
Launched to the International Space Station in June 2018, ECOSTRESS measures the surface temperature of the planet with high detail. ECOSTRESS measures variations in temperatures to within a few tenths of a degree and is able to detect temperature changes at various times of day over areas as small as a single farm. These measurements are used for a wide variety of applications, including plant stress and water use, urban heat, fires, water quality, volcanic activity, and hurricanes.
JPL built and manages the ECOSTRESS mission for NASA’s Earth Science Division in the Science Mission Directorate at NASA Headquarters in Washington. ECOSTRESS is an Earth Venture Instrument mission; the program is managed by NASA’s Earth System Science Pathfinder program at NASA’s Langley Research Center in Hampton, Virginia.
Aug. 23, 2019 – NASA Satellite Catches Tropical Storm Bailu’s U-Shape
NASA’s Aqua satellite passed over the Northwestern Pacific Ocean and captured an image of Tropical Storm Bailu that appeared to have a U-shape.
On Aug. 23 at 12:55 a.m. EDT (04:55 UTC) the MODIS instrument aboard NASA’s Aqua satellite provided a visible image of Tropical Storm Bailu in the Northwestern Pacific Ocean, northeast of the Philippines. Credit: NASA/NRL
On Aug. 23 at 12:55 a.m. EDT (0455 UTC) the Moderate Resolution Imaging Spectroradiometer or MODIS instrument aboard NASA’s Aqua satellite provided a visible image of Bailu in the Philippine Sea. The storm’s has what appears to be a U-shape because of “deepening convection wrapping counterclockwise from the southwest to northeast,” according to the Joint Typhoon Warning Center. Deepening convection means stronger evaporation and rising air. Those factors form the clouds that create thunderstorms that make up a tropical cyclone.
At 5 a.m. EDT (0900 UTC), the center of Bailu was located near latitude 19.4 degrees north and longitude 124.5 degrees east. Bailu was about 417 nautical miles south-southeast of Taipei, Taiwan. Bailu was moving to the northwest and had maximum sustained winds near 45 knots (51.7 mph/83.3 kph).
The Joint Typhoon Warning Center expects Bailu to continue to track northwestward and skim extreme southern Taiwan on Aug. 24, before making landfall in China on Aug. 25. After landfall the system is expected to quickly weaken and is forecast to dissipate by Aug. 26.
Aug. 23, 2019 – GPM Finds Heavy Rain Occurring in a Weaker Tropical Storm Ivo
Tropical Storm Ivo may have weakened in the overnight hours from Aug. 22 to Aug. 23, but the Global Precipitation Measurement mission or GPM core satellite has found that the storm is still generating heavy rainfall over the Eastern Pacific Ocean.
The GPM core satellite passed over Tropical Storm Ivo on Aug. 22 at 10:51 p.m. EDT (0251 UTC, Aug. 23). GPM found the heaviest rainfall (pink) around Ivo’s center of circulation falling at a rate of 25 mm (about 1 inch) per hour. Credit: NASA/JAXA/NRL
As Ivo was moving toward Mexico’s Clarion Island, the GPM satellite passed overhead and analyzed the rain rates throughout the storm on Aug. 22 at 10:51 p.m. EDT (0251 UTC, Aug. 23). GPM found the heaviest rainfall was occurring in a fragmented band of thunderstorms west of the center of circulation where it was falling at a rate of 40 mm (about 1.6 inch) per hour. GPM is a joint mission between NASA and the Japan Aerospace Exploration Agency, JAXA.
At 5 a.m. EDT (0900 UTC), the center of Tropical Storm Ivo was located near latitude 17.9 degrees n and longitude 114.5 degrees west. That puts the center about 455 miles (735 km) southwest of the southernmost tip of Baja California, Mexico. The National Hurricane Center or NHC said that Ivo is moving toward the north-northwest near 10 mph (17 kph), and this general motion is expected to continue for the next 2 to 3 days.
Maximum sustained winds are near 60 mph (95 kph) with higher gusts. The estimated minimum central pressure is 996 millibars.
NHC noted, “Little change in intensity is expected today, but Ivo should begin to weaken on Saturday [August 24].”
Aug. 23, 3019 – NASA’s Aqua Satellite Writing the End of Depression Chantal’s Story
Tropical Depression Chantal is winding down in the North Central Atlantic Ocean and that was confirmed by infrared data from NASA’s Aqua satellite on August 23.
On Aug. 23 at 12:45 a.m. EDT (0445 UTC), the MODIS instrument that flies aboard NASA’s Aqua satellite showed strongest storms (yellow) in Tropical Depression Chantal were in two small areas, east and west of center, where cloud top temperatures in those areas were as cold as minus 50 degrees Fahrenheit (minus 45.5 Celsius). Credit: NASA/NRL
The National Hurricane Center or NHC forecasts the end of Chantal’s life story later in the day, as the storm is forecast to become a remnant low pressure area.
On Aug. 23 at 1:30 a.m. EDT (0530 UTC), the Moderate Imaging Spectroradiometer or MODIS instrument that flies aboard NASA’s Aqua satellite used 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.
Two areas remained with strongest storms. Those areas were east and west of the center of circulation where cloud top temperatures were as cold as minus 50 degrees Fahrenheit (minus 45.5 degrees Celsius).
At 5 a.m. EDT (0900 UTC), the center of Tropical Depression Chantal was located near latitude 37.1 degrees north and longitude 40.9 degrees west. That places the center of Chantal about 765 miles (1,225 km) west of the Azores Islands. Chantal is moving toward the southeast near 8 mph (13 kph) and is expected to make a slow clockwise loop over the next few days.
Maximum sustained winds have decreased to near 30 mph (45 kph) with higher gusts. The estimated minimum central pressure is 1010 millibars.
NOAA’s National Hurricane Center noted, “Additional weakening is forecast, and Chantal is likely to degenerate into a remnant low by tonight. The remnant low could dissipate by late Sunday [Aug. 25] or Monday [Aug. 26].”
Hurricane Barbara continued to track west through the Eastern Pacific Ocean when NASA-NOAA’s Suomi NPP satellite passed overhead on July 4. Satellite imagery revealed clouds filling into Barbara’s eye as wind shear continued to weaken the storm and push the bulk of its clouds north of the center.
Hurricane Barbara continued to show an eye in visible imagery on July 4, 2019. NASA-NOAA’s Suomi NPP satellite passed over the Eastern Pacific Ocean and the VIIRS instrument aboard captured this image of the storm. Credit: NASA Worldview, Earth Observing System Data and Information System (EOSDIS)
The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard Suomi NPP provided a visible image of the storm. The VIIRS image and microwave satellite imagery indicates that Barbara is being torn apart by winds outside or around the storm. In general, wind shear is a measure of how the speed and direction of winds change with altitude. The National Hurricane Center noted that the eyewall structure appears to be disintegrating and the low-level center is located to the south of the remaining strong thunderstorms.
There are several factors weakening the once Category 4 hurricane: increasing southwesterly wind shear, dry air moving into the storm and sapping the moisture and energy, and cooler sea surface temperatures that lay ahead of the storm as it continues moving west.
At 5 a.m. EDT (0900 UTC) on July 5, NOAA’s National Hurricane Center said the eye of Hurricane Barbara was located near latitude 17.7 degrees north and longitude 132.6 degrees west. That puts the eye about 1,475 miles (2,375 km) east of Hilo, Hawaii. Barbara is moving toward the northwest near 12 mph (19 kph). The forecast calls for a gradual turn toward the west through Saturday, July 6. The estimated minimum central pressure is 980 millibars (28.94 inches).
Maximum sustained winds have decreased to near 80 mph (130 kph) with higher gusts. Hurricane-force winds extend outward up to 35 miles (55 km) from the center and tropical-storm-force winds extend outward up to 150 miles (240 km).
Barbara is on a weakening trend. 24 hours earlier the storm had maximum sustained winds near 120 mph (195 kph). Forecasters expect additional rapid weakening and Barbara is expected to become a post-tropical cyclone late on July 6.
June 28, 2019 – NASA Satellite Takes Tropical Storm Alvin’s Temperature
Cloud top temperatures are an indication of strength of tropical cyclones. The colder the cloud tops, the higher they extend in the troposphere, and colder temperatures typically indicate stronger storms. NASA’s Aqua satellite peered into Tropical Storm Alvin with infrared light to determine if the storm was intensifying.
NASA’s Aqua satellite provided an infrared picture of Tropical Storm Alvin’s cloud top temperatures on June 27 at 4:59 a.m. EDT (0859 UTC). Strongest storms with coldest cloud tops appear in purple and have temperatures as cold as or colder than minus 63 Fahrenheit (minus 53 Celsius). Credit: NASA JPL, Heidar Thrastarson
The Atmospheric Infrared Sounder or AIRS instrument aboard NASA’s Aqua satellite passed over Tropical Storm Alvin and analyzed the storm in infrared light. Infrared light provides scientists with temperature data and that is important when trying to understand the strength of the thunderstorms that make up a tropical cyclone. The higher the cloud tops, the colder and the stronger they are. So infrared light as that gathered by the AIRS instrument can identify the strongest sides of a tropical cyclone.
NASA’s Aqua satellite flew over Alvin on June 27 at 4:59 a.m. EDT (0859 UTC). AIRS detected strongest storms around the center with cloud top temperatures as cold as minus 63 degrees Fahrenheit (minus 53 degrees Celsius). Infrared data showed cloud top temperatures were getting colder, indicating stronger uplift of air, pushing those storms higher in the troposphere. Storms with cloud top temperatures that cold have the capability to produce heavy rainfall. The storm intensified over June 27 to early June 28 as winds increased from 60 to 70 mph (97 to 110 kph).
On June 28, NOAA’s National Hurricane Center forecaster Daniel Brown said, “Alvin’s satellite presentation has begun to degrade overnight with the overall cloud pattern becoming elongated from southwest to northeast. Southwesterly shear has caused the system to become less symmetric.”
Current Status of Alvin
At 5 a.m. EDT (0900 UTC) on Friday, June 28, 2019 the center of Tropical Storm Alvin was located near latitude 18.0 degrees north and longitude 116.3 degrees west. That puts the center of Alvin about 535 miles (860 km) southwest of the southern tip of Baja California, Mexico. Maximum sustained winds are near 70 mph (110 kph) with higher gusts.
Alvin is moving toward the northwest near 15 mph (24 kph), and a gradual turn toward the west-northwest with a decrease in forward speed is expected over the next couple of days. Alvin is expected to move into an area of cooler waters and where the southwesterly wind shear is forecast to increase. Those two factors are expected to cause rapid weakening during the next 24 to 36 hours. Because Alvin is a small cyclone, it is likely to suffer from the effects of the hostile environment more quickly.
The National Hurricane Center expects Alvin to weaken over the next day or two, and Alvin is forecast to become a remnant low on Saturday and should dissipate soon thereafter.
For forecast updates on Tropical Storm Alvin, visit: www.nhc.noaa.gov
