Sep. 13, 2019 – GPM Analyzes Rainfall in Bahamas from Potential Tropical Cyclone 9
As the Bahamas continue to recover from Category 5 hurricane Dorian, a new developing tropical cyclone is bringing additional rainfall to an already soaked area.
The Global Precipitation Measurement mission or GPM core satellite provided a look at those rainfall rates occurring in Potential Tropical Cyclone Nine, located over the Bahamas.
Potential Tropical Cyclone 9 developed around 5 p.m. EDT on Thursday, Sept. 12. At 11 a.m. EDT on Sept. 13, the depression triggered watches and warnings from NOAA’s National Hurricane Center. A Tropical Storm Warning is in effect for the northwestern Bahamas excluding Andros Island and a Tropical Storm Watch is in effect from Jupiter Inlet to the Flagler-Volusia County line, Fla.
Watches and warnings are already in effect. A Tropical Storm Warning is in effect for the northwestern Bahamas excluding Andros Island and a Tropical Storm Watch is in effect from Jupiter Inlet to Flagler-Volusia County line, Fla.
The GPM or Global Precipitation Measurement mission’s core satellite passed over Tropical Depression 9 on Sept. 13 at 2:26 a.m. EDT (0726 UTC). GPM found the heaviest rainfall northwest of the center where it was falling at a rate of over 40 mm (about 1.6 inch) per hour. GPM is a joint mission between NASA and the Japan Aerospace Exploration Agency, JAXA.
NOAA’s National Hurricane Center noted at 2 p.m. EDT (1800 UTC), the disturbance was centered near latitude 25.4 degrees north and longitude 74.2 degrees west. The system is expected to resume a slow motion toward the northwest and north-northwest later in the day. Maximum sustained winds are near 30 mph (45 kph) with higher gusts. The disturbance is forecast to become a tropical depression or a tropical storm later today or Saturday.
The potential tropical cyclone is expected to produce total rainfall accumulations through Sunday in the Bahamas of up to 2 to 4 inches, with isolated maximum amounts 6 inches. The U.S. Southeast Coast from central Florida into South Carolina can expect from 2 to 4 inches.
On the forecast track, the system is anticipated to move across the central and northwestern Bahamas today, and along or near the east coast of Florida Saturday and Saturday night.
NASA-NOAA’s Suomi NPP satellite passed over the Eastern Pacific Ocean in the early hours of Sept. 12 and grabbed a nighttime look at Tropical Storm Kiko.
Kiko developed on Sept. 11 as Tropical Depression 13E and strengthened into a tropical storm by 5 p.m. EDT. Once it attained tropical storm status, it was named Kiko.
On Sept. 12 at 4:54 a.m. EDT (0854 UTC), the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard NASA-NOAA’s Suomi NPP provided an infrared image of the strengthening storm. At the time of the overpass the National Hurricane Center (NHC) noted, “There’s a small patch of convection (rising air that formed thunderstorms) near the estimated center, with another larger cluster much farther south. For the most part, however, the circulation consists of a broken low- and mid-level cloud deck with a few embedded showers.” The Suomi NPP image also showed a larger band of thunderstorms had developed north of center.
At 11 a.m. EDT (1500 UTC), the center of Tropical Storm Kiko was located near latitude 16.9 degrees north and longitude 114.4 degrees west. Kiko is far from land and about 505 miles (815 km) southwest of the southern tip of Baja California, Mexico. Kiko was moving toward the west-northwest near 10 mph (17 kph) and this motion is expected to continue through Monday. Maximum sustained winds are near 40 mph (65 km/h) with higher gusts. Estimated minimum central pressure is 1004 millibars.
Some strengthening is forecast during the next 48 hours, and Kiko is expected to approach hurricane strength later this weekend.
The Atlantic Ocean’s Gabrielle has made a second transition and the Global Precipitation Measurement mission or GPM core satellite provided information about the rate in which rain was falling within the now extra-tropical storm.
Gabrielle made its first transition to a post-tropical cyclone on Sept. 6 and regained tropical storm status later that same day. Now, the storm has become extra-tropical.
The GPM or Global Precipitation Measurement mission’s core satellite passed over Tropical Storm Gabrielle in the eastern North Atlantic Ocean on Sept. 9 at 3:01 a.m. EDT (0701 UTC). GPM found the heaviest rainfall north of the center where it was falling at a rate of over 25 mm (about 1 inch) per hour. GPM is a joint mission between NASA and the Japan Aerospace Exploration Agency, JAXA.
NOAA’s National Hurricane Center noted at 11 a.m. EDT (1500 UTC) on Sept. 10, “Gabrielle has now completed its transition to an extra-tropical cyclone this morning based on the latest GOES-16 satellite imagery. The center of the storm has now become exposed with convection displaced to the north of the center, and a well-defined baroclinic zone has become established in association with the low center.”
When a storm becomes “extra-tropical” 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) of the cyclone 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.
The center of Post-Tropical Cyclone Gabrielle was located near latitude 43.9 degrees north and longitude 37.8 degrees west. That puts the center about 695 miles (1,114 km) northwest of the Azores islands. The post-tropical cyclone is moving toward the northeast at near 29 mph (46 kph), and this general motion with an increase in forward speed is expected over the next couple of days. Maximum sustained winds are near 50 mph (85 kph) with higher gusts. The estimated minimum central pressure is 998 millibars.
Gabrielle is expected to weaken over the next two days and dissipate over the far North Atlantic west of the British Isles on Thursday, Sept. 12.
Sep. 10, 2019 – NASA Finds Faxai Now Extra-tropical in Pacific Ocean
NASA’s Aqua satellite passed over the Northwestern Pacific Ocean from its orbit in space and took an image that showed vertical wind shear was weakening Faxai and the storm had become extra-tropical.
On Sept. 9, the Joint Typhoon Warning Center or JTWC posted its last advisory on the system as it continues to weaken. At 5 p.m. EDT (2100 UTC), the JTWC stated that Faxai’s center was located near latitude 39.4 degrees north and longitude 147.7 degrees east. That is about 254 nautical miles east-southeast of Misawa, Japan. Faxai was moving to the east-northeast. Maximum sustained winds were near 45 knots (52 mph/83 kph). Faxai had begun its extra-tropical transition as it entered the baroclinic zone over the colder waters.
On Sept. 10, 2019 at 0310 UTC (Sept. 9 at 11:10 p.m. EDT) the Moderate Resolution Imaging Spectroradiometer or MODIS instrument aboard NASA’s Aqua satellite provided a visible image of Tropical Storm Faxai that showed wind shear was pushing clouds and storms east of the center.
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 imagery showed the system continued to rapidly decay and elongate. Faxai had transitioned into an extra-tropical storm and was a strong gale-force cold core low-pressure area with a large wind field. A tropical cyclone becomes extra-tropical when its warm core becomes a cold core, like a typical mid-latitude low-pressure area.
When a storm becomes “extra-tropical”, 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) of the cyclone 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.
Faxai will continue to track through the Northern Pacific Ocean as an extra-tropical storm for the next several days.
Sep. 09, 2019 – NASA Finds Tropical Storm Faxai’s Heavy Rainmaking Storms Off-Shore from Japan
The big island of Japan received Tropical Storm Faxai and NASA’s Aqua satellite provided forecasters at the Joint Typhoon Warning Center infrared data and cloud top temperature information that revealed the most powerful storms just off-shore when the satellite flew overhead.
NASA researches tropical cyclones and one of the ways NASA does that is with infrared data that provides temperature information. Cloud top temperatures provide information to forecasters about where the strongest storms are located within a tropical cyclone. Tropical cyclones do not always have uniform strength, and some sides have stronger sides than others. The stronger the storms, the higher they extend into the troposphere, and they have the colder cloud temperatures.
NASA’s Aqua satellite analyzed the storm on Sept. 8 at 11:59 p.m. EDT (Sept. 9 at 0359 UTC) using the Atmospheric Infrared Sounder or AIRS instrument. AIRS found coldest cloud top temperatures as cold as or colder than minus 63 degrees Fahrenheit (minus 53 degrees Celsius) around Faxai’s center and in a large band east of center. NASA research has shown that cloud top temperatures that cold indicate strong storms that have the capability to create heavy rain.
Satellite imagery has revealed that Faxai continues to decay as it moves east of Honshu, Japan over the cooler waters of the Pacific Ocean.
Typhoon Faxai made landfall just east of Tokyo on Sept. 8. Japan’s Kyodo News Service reported that 3 people were killed and 700,000 people were left without power.
On Sept. 8 at 11:59 p.m. EDT (Sept. 9 at 0359 UTC) the center of Faxai was located near latitude 38.2 degrees north and longitude 144.5 degrees west. That places the center 289 nautical miles northeast of Yokosuka, Japan. Faxai is moving toward the east-northeast. Maximum sustained winds are near 55 knots.
Faxai is moving northeast and forecasters at the Joint Tropical Storm Warning Center expect Faxai will become extra-tropical.
Sep. 09, 2019 – NASA Finds Gabrielle’s Strength on its Northern Side
NASA’s Aqua satellite passed over the Central Atlantic Ocean and provided a visible view of Tropical Storm Gabrielle that helped pinpoint its strongest side.
On Sept. 8, 2019 at 2:35 p.m. EDT (1635 UTC), the Moderate Resolution Imaging Spectroradiometer or MODIS instrument aboard NASA’s Aqua satellite provided a visible image of Gabrielle that showed strongest thunderstorms northeast of the center.
The MODIS image also showed that there were also fragmented bands of strong thunderstorms south and southwest of the center.
On Sept. 9, NOAA’s National Hurricane Center or NHC said, “Deep convection associated with Gabrielle has become somewhat less organized overnight with the center located near the northeastern portion of the coldest cloud tops.”
NASA satellites provide research data on structure, rainfall, winds and temperature of tropical cyclones. Those data are shared with forecasters at NHC to incorporate in their forecasts.
NHC noted at 5 a.m. EDT (0900 UTC), on Sept. 9 that the center of Tropical Storm Gabrielle was located near latitude 37.7 degrees north and longitude 48.5 degrees west. Gabrielle’s center is about 1,170 miles (1.885 km) west of the Azores Islands.
Gabrielle is moving toward the north-northeast near 16 mph (26 kph). A turn toward the northeast with an increase in forward speed is expected today, Sept. 9 and a northeastward motion at an even faster forward speed is expected on Tuesday and Wednesday. Maximum sustained winds are near 60 mph (95 kph) with higher gusts. The estimated minimum central pressure is 997 millibars.
NHC said, “Little change in strength is expected today, but a weakening trend is likely to begin tonight.” Weakening is expected because Gabrielle will be moving into an area of outside winds (vertical wind shear) and cooler sea surface temperatures.
Gabrielle is expected to become an extratropical low pressure area by Tuesday night, Sept. 10 and the extratropical low is predicted to slowly weaken and be absorbed by a larger low pressure system over the northeastern Atlantic in a little more than 3 days
On Monday morning, September 9, Hurricane Dorian was a post-tropical storm after a mid-latitude weather front and cold seas had altered its tropical characteristics over the weekend. NASA compiled data on Hurricane Dorian and created a map that showed the heavy rainfall totals it left in its wake from the Bahamas to Canada.
On Saturday and Sunday, Sept. 7 and 8, Hurricane Dorian struck eastern Canada, causing wind damage and bringing heavy rainfall. According to the Associated Press, a peak of 400,000 people were without power in Nova Scotia, Canada, because of Dorian.
At NASA’s Goddard Space Flight Center in Greenbelt, Maryland, a graphic was produced that shows precipitation that fell during the almost two-week period from August 27 to the early hours of Sept. 9. The near-real-time rain estimates come from the NASA’s IMERG algorithm, which combines observations from a fleet of satellites, in near real time, to provide near-global estimates of precipitation every 30 minutes.
This year, NASA began running an improved version of the IMERG algorithm that does a better job estimating precipitation at high latitudes, specifically north of 60 degrees North latitude. The post-tropical remnants of Hurricane Dorian were approaching this cold region at the end of the analysis period. While the IMERG algorithm is still unable to estimate precipitation falling over ice-covered surfaces (such as Greenland), IMERG can now give a more complete picture of the water cycle in places such as Canada, which is, for the most part, free of snow cover at this time of year.
In addition to rainfall totals, the map includes preliminary reports of tornadoes from 4:50 AM to 5:00 PM EDT on September 5 in North Carolina as provided by NOAA’s Storm Prediction Center.
IMERG showed largest rainfall amounts of more than 36 inches over the Bahamas and in an area off the coast of northeastern Florida. A large area of rainfall between 16 and 24 inches fell in many areas off the U.S. East Coast. Areas include those from South Carolina to the Bahamas, another off the North Carolina coast, a third area off the coasts of southern New Jersey, Delaware and Maryland, and the New England states.
By combining NASA precipitation estimates with other data sources, we can gain a greater understanding of major storms that affect our planet.
On Monday, Sept. 9 at 0300 UTC (Sept. 8 a t 11 p.m. EDT), NOAA’s National Hurricane Center (NHC) issued the final advisory on Dorian. At that time, Dorian had moved into the Labrador Sea and its impacts on Newfoundland were beginning to subside. Post-tropical cyclone Dorian had maximum sustained winds near 50 knots (57 mph/93 kph). It was centered near 52.1 degrees north latitude and 53.4 degrees west longitude. That puts the center about 375 miles north of Cape Race, Newfoundland, Canada. Dorian was speeding to the east-northeast at 21 knots. Minimum central pressure was 980 millibars.
On Sept. 9, additional rainfall totals expected from Dorian in far eastern Quebec, Newfoundland and Labrador are expected to be less than 1 inch. Meanwhile, life-threatening rip tide and surf conditions are expected to affect mid-Atlantic and New England coasts of the U.S., as well as the coast of Atlantic Canada.
The NHC said the cyclone will continue into the open Atlantic, where it will dissipate south of Greenland.
Sep. 08, 2019 – NASA Sees Post-Tropical Cyclone Dorian Over Eastern Canada
NASA’s Aqua satellite provided an infrared look at Post-Tropical Cyclone Dorian lashing parts of eastern Canada.
A tropical cyclone is the general name for a hurricane, tropical storm, depression or typhoon. NASA provides data and research on tropical cyclones to analyze intensification, weakening, structure, and behavior. NOAA’s National Hurricane Center uses that data in their forecasts.
NASA’s Views of Dorian Before and After Landfall
Instruments aboard NASA’s Aqua satellite use visible, microwave and infrared light to analyze various aspects of a tropical cyclone.
On Sept. 7 at 1:30 p.m. EDT (1730 UTC), the MODIS instrument that flies aboard NASA’s Aqua satellite provided a visible image that clearly showed Dorian’s center just south of Nova Scotia, Canada.
Dorian moved north and five hours later, Post-Tropical Dorian made landfall at 6:15 p.m. EDT near Sambro Creek in Nova Scotia, Canada, or about 15 miles (25 km) south of Halifax. The estimated maximum sustained winds at landfall were 100 mph (155 kph) and the estimated central pressure was 958 millibars.
After Dorian had crossed over Nova Scotia, at 2 a.m. EDT on Sept. 8, it was centered about 5 miles (10 km) north of the Magdalen Islands, near latitude 47.5 degrees north and longitude 61.8 degrees west in the Gulf of St. Lawrence.
NASA’s Aqua satellite passed over Dorian again and looked at the storm in infrared light. NASA 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 Sept. 8 at 3:05 a.m. EDT (0705 UTC), the Moderate Imaging Spectroradiometer or MODIS instrument that flies aboard NASA’s Aqua satellite gathered infrared data on Dorian and showed the storm bringing rains and gusty winds to areas of Newfoundland, Labrador, Quebec south, Prince Edward Island and Nova Scotia. MODIS showed thunderstorms had cloud top temperatures as cold as minus 50 degrees Fahrenheit (minus 45.5 Celsius).
What is a Post-Tropical Storm?
A Post-Tropical Storm is a generic term for a former tropical cyclone that no longer possesses sufficient tropical characteristics to be considered a tropical cyclone. Former tropical cyclones that have become fully extratropical, subtropical, or remnant low pressure areas, are three classes of post-tropical cyclones. In any case, they no longer possesses sufficient tropical characteristics to be considered a tropical cyclone. However, post-tropical cyclones can continue carrying heavy rains and high winds.
Warnings and Watches on Sept. 8, 2019
NOAA’s National Hurricane Center (NHC) noted on Sept. 8 that a Hurricane Warning is in effect for eastern Nova Scotia from Ecum Secum to Brule, and western Newfoundland from Indian Harbour to Hawke’s Bay. A Hurricane Watch is in effect for the Magdalen Islands. A Tropical Storm Warning is in effect for Prince Edward Island, Magdalen Islands, from Stone’s Cove to Indian Harbour, from Hawke’s Bay to Fogo Island and from Mutton Bay to Mary’s Harbour.
The Canadian Meteorological Service issued many warnings and watches on Sunday, September 8, 2019 for Newfoundland, Labrador, Quebec south, Prince Edward Island and Nova Scotia.
NHC noted that at 8 a.m. EDT (1200 UTC), the center of Post-Tropical Cyclone Dorian was located near latitude 49.4 degrees north and longitude 60.6 degrees west. Dorian’s center was about 55 miles (90 km) east-northeast of Heath Point, Anticosti Island, Canada, and about 90 miles (145 km) northwest of Cape St. George, Newfoundland, Canada. A sustained wind of 55 mph (89 km/h) with a gust to 73 mph (117 kph) was reported at Heath Point on Anticosti Island.
The post-tropical cyclone is moving toward the north-northeast near 26 mph (43 kph), and this general motion with a turn to the northeast is expected during the next couple of days. Maximum sustained winds are near 80 mph (130 kph) with higher gusts. These winds are occurring mainly over water. The post-tropical cyclone is forecast to drop below hurricane strength after passing Newfoundland later today.
The estimated minimum central pressure is 961 millibars.
What’s Next for Dorian?
Dorian is expected to remain a powerful storm through this afternoon, but the global models show steady weakening after the center moves northeast of Newfoundland tonight. Forecasters at NHC said “Dorian should continue north-northeastward today, then turn east-northeastward over the North Atlantic as it remains embedded within the mid-latitude westerlies.”
The forecast track takes Dorian south of Greenland on its trek across the Northern Atlantic. The post-tropical cyclone should should be absorbed by another extratropical low over the North Atlantic in 2 to 3 days.
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. 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.
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
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 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).
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.
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.
Sep. 06, 2019- NASA Finds Classic Comma-Shape in Tropical Storm Faxai
NASA’s Aqua satellite passed over the Northwestern Pacific Ocean and looked at comma-shaped Tropical Storm Faxai in infrared light.
At 11 a.m. EDT (1500 UTC), the Joint Typhoon Warning Center or JTWC reported that Tropical Storm Faxai had maximum sustained winds near 55 knots (63 mph/102 kph). JTWC said the storm is intensifying and that is evident by the powerful thunderstorms that NASA’s Aqua satellite found using infrared imagery.
Faxai was located near 24.7 degrees north latitude and 148.1 degrees east longitude, about 371 nautical miles east of Iwo To Island, Japan. Faxai was moving to the west-northwest.
On Sept. 6 at 11:40 a.m. EDT (1540 UTC), the Moderate Imaging Spectroradiometer or MODIS instrument that flies aboard NASA’s Aqua satellite used infrared light to analyze the strength of storms within the storm.
NASA researches tropical cyclones with satellites, field missions and computer modeling to determine how they rapidly intensify, develop and behave.
Tropical cyclones are made of up hundreds of thunderstorms, and infrared data can show where the strongest storms are located. They can do that because infrared data provides temperature information, and the strongest thunderstorms that reach highest into the atmosphere have the coldest cloud top temperatures.
MODIS found those strongest storms were around the center of circulation 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. Those strong storms were surrounded by slightly less powerful storms that also extended in a band of thunderstorms that formed a “tail” stretching from the north to the east. That large, thick band of strong thunderstorms helped give Faxai the comma shape.
Faxai is forecast to move to the west-northwest and turn north after three days where it is forecast to make landfall near Tokyo at 80 knots (92 mph) on Sept. 8.