Peipah – Northwestern Pacific Ocean

Sep. 16, 2019 – NASA Finds Tropical Depression Peipah Dissipating

NASA’s Terra satellite passed over the northwestern Pacific Ocean and provided a final view of Tropical Depression Peipah.

Terra image of Peipah
On Sept. 16, the MODIS instrument aboard NASA’s Terra satellite provided a visible image of Peipah. The storm had diminished to a swirl of clouds, with only a small area of strong thunderstorms southwest of the center. Wind shear from the northeast pushed those storms southwest of center. Credit: NASA Worldview, Earth Observing System Data and Information System (EOSDIS)

Peipah developed on Sept. 14 as a depression. It was the seventeenth (17W) tropical depression of the Northwestern Pacific Ocean typhoon season. On Sept. 15 at 11 a.m. EDT (1500 UTC) the depression strengthened into a tropical storm with maximum sustained winds near 35 knots (40 mph) and was renamed Peipah. On Sept. 16, Peipah weakened back to a depression.

On Sept. 16, the Moderate Resolution Imaging Spectroradiometer or MODIS instrument aboard NASA’s Terra satellite provided a visible image of Peipah. The storm had diminished to a swirl of clouds, with only a small area of strong thunderstorms southwest of the center. Wind shear from the northeast pushed those storms southwest of 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.

Tropical Depression Peipah was dissipating on Sept. 16 at 11 a.m. EDT (1500 UTC). It was centered near 24.8 degrees north latitude and 142.8 degrees east longitude, about 82 miles east of Iwo To Island, Japan. Peipah was moving to the northwest and had maximum sustained winds near 25 knots.

The Joint Typhoon Warning Center issued their final warning on the system as it continued to dissipate.

By Rob Gutro
NASA’s Goddard Space Flight Center

Kiko – Eastern Pacific Ocean

Sep. 16, 2019 – NASA Finds Kiko Weakening in the Eastern Pacific

NASA’s Aqua satellite provided forecasters at the National Hurricane Center with infrared data and cloud top temperature information on Hurricane Kiko. Wind shear was affecting the storm and had closed the eye.

AIRS image of Kiko
On Sept. 16 at 5:41 a.m. EDT (0941 UTC) the AIRS instrument aboard NASA’s Aqua satellite analyzed cloud top temperatures of Hurricane Kiko in infrared light. AIRS found coldest cloud top temperatures (purple) of strongest thunderstorms were as cold as or colder than minus 63 degrees Fahrenheit (minus 53 degrees Celsius) around the center and in a large bands east and west of center. Credit: NASA JPL/Heidar Thrastarson

On Monday, September 16, 2019, microwave data and satellite imagery continue to indicate that the core of Kiko is being disrupted. Wind shear from the northeast is preventing Kiko from having a closed eyewall circulation. That means that the storm is subject to outside winds and can weaken.

NASA researches tropical cyclones. 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. The AIRS instrument is one of six instruments flying on board NASA’s Aqua satellite, launched on May 4, 2002.

The AIRS infrared data no longer showed an eye in Kiko, indicating that the wind shear from the northeast had filled the center with clouds.

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.

AIRS found coldest cloud top temperatures as cold as or colder than minus 63 degrees Fahrenheit (minus 53 degrees Celsius) around Kiko’s center and in a large bands east and west of center. NASA research has shown that cloud top temperatures that cold indicate strong storms that have the capability to create heavy rain.

At 11 a.m. EDT (1500 UTC), the center of Hurricane Kiko was located near latitude 17.3 degrees north and longitude 123.7 degrees west. That put the center about 975 miles (1,570 km) west-southwest of the southern tip of Baja California, Mexico. Kiko is moving toward the west near 5 mph (7 kph), and this motion is expected to continue through tonight.

Maximum sustained winds have decreased to near 105 mph (165 kph) with higher gusts. Kiko is a small tropical cyclone. Hurricane-force winds extend outward up to 15 miles (30 km) from the center and tropical-storm-force winds extend outward up to 60 miles (95 km). The estimated minimum central pressure is 971 millibars.

NHC forecasters expect a west-southwestward motion on Sept. 17 followed by a turn back to the west on Wednesday. Gradual weakening is expected during the next couple of days.

For updated forecasts, visit: www.nhc.noaa.gov

By Rob Gutro
NASA’s Goddard Space Flight Center  

Humberto (Atlantic Ocean)

Sep. 16, 2019 – NASA Finds Humberto Strengthening off the Florida Coast

NASA’s Aqua Satellite provided a visible image of Tropical Storm Humberto as it was strengthening off the Florida coast on Sept. 15. Humberto became a hurricane late in the day.

Aqua image of Humberto
On Sept. 15, the MODIS instrument that flies aboard NASA’s Aqua provided a visible image of Tropical Storm Humberto spinning off the eastern coast of Florida and strengthening. Powerful thunderstorms circled the center and a large band of thunderstorms wrapped into the low-level center from the east. Credit: NASA Worldview, Earth Observing System Data and Information System (EOSDIS).

On Sept. 15, the Moderate Imaging Spectroradiometer or MODIS instrument that flies aboard NASA’s Aqua satellite provided a visible image of Tropical Storm Humberto spinning off the eastern coast of Florida and strengthening. Powerful thunderstorms circled the center and a large band of thunderstorms wrapped into the low-level center from the east. Humberto became a hurricane on Sept. 15 at 11 p.m. EDT.

Earlier that day at 2:11 p.m. EDT (1811 UTC) the Atmospheric Infrared Sounder (AIRS) instrument aboard NASA’s Aqua satellite analyzed Humberto’s cloud top temperatures in infrared light. AIRS found coldest cloud top temperatures (purple) of strongest thunderstorms were as cold as or colder than minus 63 degrees Fahrenheit (minus 53 degrees Celsius) around the center. NASA research has shown that storms with cloud top temperatures that cold can produce heavy rainfall.

AIRS infrared image of Humberto
On Sept. 15 at 2:11 p.m. EDT (1811 UTC) the AIRS instrument aboard NASA’s Aqua satellite analyzed Humberto’s cloud top temperatures in infrared light. AIRS found coldest cloud top temperatures (purple) of strongest thunderstorms were as cold as or colder than minus 63 degrees Fahrenheit (minus 53 degrees Celsius) around the center. Credit: NASA JPL/Heidar Thrastarson

On Sept. 16, Humberto was stirring up the seas and creating hazardous conditions. Humberto continued to get better organized to the west of Bermuda and was pushing large swells that were affecting much of the southeastern United States coastline. The National Hurricane Center (NHC) cautioned that interests in and around Bermuda should monitor the progress of Humberto since a Tropical Storm Watch will likely be required for Bermuda later in the day.

At 11 a.m. EDT (1500 UTC), the center of Hurricane Humberto was located near latitude 29.9 degrees north and longitude 76.5 degrees west making the center about 710 miles (1,145 km) west of Bermuda. Humberto is moving toward the east-northeast near 7 mph (11 kph). This general motion with a gradual increase in forward speed is expected through early Thursday.

Near visible Aqua image of Humberto
On Sept. 15 at 2:11 p.m. EDT (1811 UTC) the AIRS instrument aboard NASA’s Aqua satellite provided a near-visible image of Tropical Storm Humberto as it was strengthening into a hurricane. Credit: NASA JPL/Heidar Thrastarson

Data from an Air Force Reserve reconnaissance aircraft indicate that maximum sustained winds are near 85 mph (140 kph) with higher gusts. The minimum central pressure recently measured by reconnaissance aircraft was 978 millibars.

In the NHC discussion, Forecaster Stacy Stewart noted, “Humberto has been strengthening at a rate of 20 knots per 24 hours since this time yesterday, and that trend is expected to continue for the next day or so given the warm water beneath the hurricane and a continued favorable upper-level outflow pattern. The hurricane is expected to peak as a major hurricane in 36 to 48 hours.”

On the forecast track, the center of Humberto is forecast to approach Bermuda Wednesday night, Sept. 18. NHC forecasters said that strengthening is expected during the next 48 hours, and Humberto could become a major hurricane by Tuesday night, Sept. 17.

For updated forecasts, visit: www.nhc.noaa.gov

By Rob Gutro
NASA’s Goddard Space Flight Center

Humberto – Atlantic Ocean

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.

GPM image of Potential Tropical Cyclone 9
The GPM core satellite passed over developing Potential Tropical Cyclone 9 on Sept. 13 at 2:26 a.m. EDT (0726 UTC). GPM found the heaviest rainfall (pink) northwest of the center where it was falling at a rate of over 40 mm (about 1.6 inch) per hour. Lighter rainfall rates (yellow and blue) were measured throughout the rest of the storm. Credit: NASA/JAXA/NRL

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.

For updated forecasts, visit: www.nhc.noaa.gov

By Rob Gutro
NASA’s Goddard Space Flight Center

Kiko – Eastern Pacific Ocean

Sep. 13, 2019 – NASA-NOAA Satellite‘s Night-time Look at Tropical Storm Kiko

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.

Suomi NPP image of Kiko
NASA-NOAA’s Suomi NPP satellite passed over Tropical Storm Kiko in the Eastern Pacific Ocean and the VIIRS instrument aboard captured this image of the storm on Sept. 12 at 4:54 a.m. EDT (0854 UTC). Credit: NASA/NOAA/NRL

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.

For updated forecasts, visit: www.nhc.noaa.gov

By Rob Gutro
NASA’s Goddard Space Flight Center

Gabrielle – Atlantic Ocean

Sep. 10, 2019 – GPM Finds Rainfall Waning in Extra-Tropical Storm Gabrielle

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.

GPM image of Gabrielle
The GPM core satellite passed over Post-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 (yellow) north of the center where it was falling at a rate of over 25 mm (about 1 inch) per hour. Credit: NASA/JAXA/NRL

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.

By Rob Gutro
NASA’s Goddard Space Flight Center

Faxai (was 14W) – Northwestern Pacific Ocean

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.

Aqua image of Faxai
On Sept. 10, 2019 at 0310 UTC (Sept. 9 at 11:10 p.m. EDT) the MODIS instrument aboard NASA’s Aqua satellite provided a visible image of extra-tropical storm Faxai that showed wind shear was pushing clouds and storms east of the center and elongating the storm. Credit: NASA/NRL

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.

By Rob Gutro
NASA’s Goddard Space Flight Center

Faxai (was 14W) – Northwestern Pacific Ocean

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.

AIRS image of Faxai
On Sept. 8 at 11.59 p.m. EDT (Sept. 9 at 0359 UTC) the AIRS instrument aboard NASA’s Aqua satellite analyzed cloud top temperatures of Tropical Storm Faxai in infrared light. AIRS found coldest cloud top temperatures (purple) of strongest thunderstorms were as cold as or colder than minus 63 degrees Fahrenheit (minus 53 degrees Celsius) around the center and in a large band east of center. Credit: NASA JPL/Heidar Thrastarson

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.

For updated forecasts from the Japan Meteorological Agency, visit: https://www.jma.go.jp/en/typh/

By Rob Gutro
NASA’s Goddard Space Flight Center  

Gabrielle – Atlantic Ocean

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.

Aqua image of Gabrielle
On Sept. 8, 2019 at 2:35 p.m. EDT (1635 UTC) the MODIS instrument aboard NASA’s Aqua satellite provided a visible image of Gabrielle moving through the Central Atlantic Ocean. Credit: NASA/NRL

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

For updated forecasts, visit: www.nhc.noaa.gov

By Rob Gutro
NASA’s Goddard Space Flight Center

Dorian – Atlantic Ocean

Sep. 09, 2019 – NASA Estimates Hurricane Dorian’s Massive Rainfall Track

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.

Rainfall data regarding Dorian from IMERG
At one-day intervals, the image shows the distance that tropical-storm force (39 mph) winds extended from Hurricane Dorian’s low-pressure center, as estimated by the National Hurricane Center. The Saffir-Simpson hurricane-intensity category is the number following the “H” in the label on the image. “TS” or “PT” indicate times when the storm was either at tropical storm strength or when the storm was categorized as post-tropical. Red circles over North Carolina indicate preliminary reports of tornadoes on Sept. 5. Credit: NASA Goddard

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.

By Owen Kelley / Rob Gutro
NASA’s Goddard Space Flight Center