Dorian – Atlantic Ocean

Sep. 03, 2019 – NASA’s IMERG Estimates Hurricane Dorian’s Rain

In the early hours of Tuesday, September 3, Hurricane Dorian had been stationary over the island of Grand Bahama for 18 hours, most of the time as a category 5 hurricane. Storm-total rain accumulation over parts of Grand Bahama and Abaco Islands have exceeded 24 inches according to NASA satellite-based estimates.

IMERG data on rainfall from Dorian
NASA’s IMERG storm-total rain accumulation over parts of Grand Bahama and Abaco islands have exceeded 24 inches according to NASA satellite-based estimates. The graphic also shows the distance that tropical-storm force (39 mph) winds extend from Hurricane Dorian’s low-pressure center, as reported by the National Hurricane Center. The symbols H and TS represent a hurricane of various Saffir-Simpson categories or a tropical storm, respectively. Image Credit: NASA Goddard

On early Tuesday morning, Dorian’s central pressure had risen and its wind intensity had dropped to category 4 on the Saffir-Simpson scale.  In addition, Dorian had experienced an eyewall replacement cycle on September 2, so by Tuesday morning Sept. 3, the geographic extent of its tropical-storm-force winds had expanded.

These rain estimates come from the NASA IMERG algorithm, which combines observations from a fleet of satellites, in near-realtime, to provide global estimates of precipitation every 30 minutes. The storm-total rainfall at a particular location varies with the forward speed of the hurricane, with the size of the hurricane’s wind field, and with how vigorous the updrafts are inside of the hurricane’s eyewall.

IMERG, or the Integrated Multi-satellitE Retrievals for GPM (IMERG) data product is generated by NASA’s Precipitation Processing System every half hour with a 6 hour latency from the time of data acquisition. It is produced using data from the satellites in the GPM or Global Precipitation Measurement mission constellation of satellites, and is calibrated with measurements from the GPM Core Observatory as well as rain gauge networks around the world.

IMERG is an example of the research role that NASA has in hurricanes  – developing observational tools and building computer models to better understand the behavior of tropical cyclones. NASA’s research data is utilized by NOAA’s National Hurricane Center (NHC) to enhance their forecasts.

On Tuesday, September 3, 2019, at 8 a.m. EDT (1200 UTC), NHC reported at the eye of Hurricane Dorian was located by reconnaissance aircraft and NOAA Doppler radar near latitude 27.1 degrees North and longitude 78.4 degrees West. NHC said Dorian is beginning to move northwestward at about 1 mph (2 kph), and a slightly faster motion toward the northwest or north-northwest is expected later today and tonight.

At present maximum sustained winds are near 120 mph (195 kph) with higher gusts.  Dorian is a category 3 hurricane on the Saffir-Simpson Hurricane Wind Scale.  Dorian is expected to remain a powerful hurricane during the next couple of days. Hurricane-force winds extend outward up to 45 miles (75 km) from the center, and tropical-storm-force winds extend outward up to 160 miles (260 km). The latest minimum central pressure reported by reconnaissance aircraft is 952 mb (28.11 inches).

NHC forecasts a turn toward the north by Wednesday evening, followed by a turn to the north-northeast Thursday morning.  On this track, the core of extremely dangerous Hurricane Dorian will gradually move north of Grand Bahama Island through this evening. The hurricane will then move dangerously close to the Florida east coast late today through Wednesday evening, very near the Georgia and South Carolina coasts Wednesday night and Thursday, and near or over the North Carolina coast late Thursday.

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

For more about NASA’s IMERG, visit: https://pmm.nasa.gov/gpm/imerg-global-image

By Owen Kelly / with NOAA’s NHC Update
NASA’s Goddard Space Flight Center

Dorian – Atlantic Ocean

Sep. 02, 2019 – Update #2  4:00 pm EDT – NASA Overhead as Dangerous Hurricane Dorian Takes Aim at Grand Bahamas

Dangerous Hurricane Dorian has weakened slightly and is now a Category 4 storm as it continues to spin over the Bahamas.  Dorian has slowed to a crawl in terms of speed of movement only moving at west-northwest at about 1 mph (2 km/h).  This means that the Bahamas will continue to get lashed by this monstrous storm and the amount of rainfall totals for the area continue to grow. The National Hurricane Center (NHC) has reported that the eye of the hurricane has begun to wobble a bit over Grand Bahama Island.  It is expected to stay over the island for much of the day causing extreme destruction.

Astronaut Christina Koch captured this image from the International Space Station earlier this morning.

Image of Dorian from ISS
Astronaut Christine Koch of the International Space Station captured this image of Hurricane Dorian outside the ISS windows the morning of Sep. 02, 2019. Credit: NASA

NOAA-20 observed Hurricane Dorian at 2:13 am EDT (0613 UTC) on the extreme western edge of the scan (image below). It provided an image of the classic presentation of a strong hurricane, with a nearly symmetrical circulation. Tropospheric gravity waves coming off the convection surrounding the central circulation could be seen in the infrared imagery. The Day Night Band imagery (second image below) showed the general structure of the storm with some lightning streaks. In addition, some possible mesospheric gravity waves seemed to be near the circulation center.

NOAA-20 image of Hurricane Dorian
NOAA-20 observed Hurricane Dorian at 2:13 am EDT (0613 UTC) on the extreme western edge of the scan. Credit: NASA/NOAA/UWM-SSEC-CIMSS/William Straka III
NOAA-20 day night band image of Dorian
The Day Night Band on the NOAA-20 satellite showed the general structure of the storm with some lightning streaks. In addition, some possible mesospheric gravity waves seemed to be near the circulation center. Also the lights from the capital city of Nassau could be seen scattering light through the clouds, which were relatively thinner as compared to areas nearer the eye of the storm. Credit: NASA/NOAA/UWM-SSEC-CIMSS/William Straka III

NOAA/NASA’s Suomi NPP satellite flew over Dorian about 50 minutes later at 3:03 am EDT (0703 UTC) and it had the most ideal position for observing the eye of Dorian (image below) . Suomi NPP’s infrared imagery showed the classic presentation of a strong hurricane, though slightly rotated. The lights from the capital city of Nassau could also be seen through the clouds.

Suomi NPP Image of Dorian
NOAA/NASA’s Suomi NPP satellite flew over Dorian about 50 minutes later at 3:03 am EDT (0703 UTC) and it had the most ideal position for observing the eye of Dorian. Suomi NPP’s infrared imagery showed the classic presentation of a strong hurricane, though slightly rotated. Credit: NASA/NOAA/UWM-SSEC-CIMSS/William Straka III
Suomi NPP image of Dorian
NASA NOAA’s Suomi NPP satellite image provided a very clear, very detailed image of Dorian’s eye in this image taken on Sep. 02, 2019 at 2:13 am EDT. Credit: NASA/NOAA/UWM-SSEC-CIMSS/William Straka III

The MiRS rain rate product (image below) on NASA NOAA’s Suomi NPP satellite also showed the rain wrapping into the circulation center.

Suomi NPP image of Dorian showing rainfall rates
The MiRS instrument on NASA NOAA’s Suomi-NPP satellite shows rainfall rates within the storm as well as showing the rain wrapping around the eye of the hurricane. Credit: NASA/NOAA/UWM-SSEC-CIMSS/William Straka III

As of the NHC’s update at Dorian is producing maximum sustained winds of 145 mph (230 km/h) with wind gusts of 190 mph (305 km/h).  The storm is located latitude 26.8N and longitude 78.4W which is about 25 miles (40 km) northeast of Freeport, Grand Bahama Island and about 105 miles (170 km) east of West Palm Beach, FL. The minimum central pressure is 940 Mb.

For the latest information on Dorian, visit: https://www.nhc.noaa.gov

By Lynn Jenner
NASA Goddard Space Flight Center

Dorian – Atlantic Ocean

Sep. 02, 2019- Update #1 – 9:00am EDT – Destructive Dorian Lashing Grand Bahama Island

Hurricane Dorian is breaking records over the Bahamas as the most destructive hurricane to ever hit the Bahama Islands. Catastrophic winds with gusts over 200 mph are smashing through the islands leaving devastation in their wake. Storm surge of 18 to 23 feet above normal tide levels with higher destructive waves are expected throughout the storm’s passing.

On Dorian’s current track and speed of movement, the core of extremely dangerous Hurricane Dorian will continue to pound Grand Bahama Island through much of today and tonight. The hurricane will move dangerously close to the Florida east coast tonight through Wednesday evening.

NASA’s Global Precipitation Measurement mission (GPM) was on hand to measure the amount of rainfall that the Bahama Islands are experiencing now.

GPM imagea of Dorian
These rain estimates come from the NASA IMERG algorithm, which combines observations from a fleet of satellites, in near-realtime, to provide global estimates of precipitation every 30 minutes. The storm-total rainfall at a particular location varies with the forward speed of the hurricane, with the size of the hurricane’s wind field, and with how vigorous the updrafts are inside of the hurricane’s eyewall. The graphic also shows the distance that tropical-storm force (39 mph) winds extend from Hurricane Dorian’s low-pressure center, as reported by the National Hurricane Center. The geographic extent of the tropical-storm strength winds has expanded throughout Dorian’s lifetime. The symbols H and TS represent a hurricane of various Saffir-Simpson categories or a tropical storm, respectively. Visualization by NASA Goddard.

On Monday morning, September 2, Hurricane Dorian was over the island of Grand Bahama as a category 5 storm. As has been the case for the past several days, Dorian’s inner core continues to produce 6 to 14 inches of rain accumulation. Hurricane Dorian’s forward motion has slowed to walking pace, so future updates to this rain-accumulation map may show greater accumulation over Grand Bahama than elsewhere along the storm’s path.

AIRS image of Dorian
On Sep. 01, 2019, at 2:05 am EDT (0705 UTC) the Aqua satellite using the AIRS instrument analyzed temperatures within Hurricane Dorian. Cloud top temperatures within Dorian were as cold as or colder than minus 50 degrees Fahrenheit (minus 45.5 degrees Celsius). Infrared data provides temperature information, and the strongest thunderstorms that reach high into the atmosphere have the coldest cloud top temperatures. In this image, the amount of purple (coldest temperatures) surrounding the eye shows the huge and massive number of thunderstorms that continue to circle around the still very well-defined eye. Credit: NASA JPL/Heidar Thrastarson

NASA’s Aqua satellite captured this image of Dorian at 2:05 am EDT (0705 UTC) using its AIRS (Atmospheric Infrared Sounder) instrument analyzed temperatures within Hurricane Dorian. Cloud top temperatures within Dorian were as cold as or colder than minus 50 degrees Fahrenheit (minus 45.5 degrees Celsius). Infrared data provides temperature information, and the strongest thunderstorms that reach high into the atmosphere have the coldest cloud top temperatures. In this image, the amount of purple (coldest temperatures) surrounding the eye shows the huge and massive number of thunderstorms that continue to circle around the still very well-defined eye.

At present Dorian is located at latitude 26.7N and longitude 78.3W which is about 30 miles (50 km) east-northeast of Freeport, Grand Bahama Island and about 115 miles (185 km) east of West Palm Beach, FL.  Maximum sustained winds are now 165 mph (270 km/h) down from a high of 185 mph (298 km/h).  The present movement of storm is west at 1 mph (2 km/h) leaving the storm basically parked in location for hours. The minimum central pressure inside the storm is 916 mb.

For more updates on this storm, visit: https://www.nhc.noaa.gov

By Lynn Jenner
NASA Goddard Space Flight Center

 

Dorian – Atlantic Ocean

Sep. 01, 2019 – Update #3 – 3:00 pm – Devastating Category 5 Hurricane Dorian Makes a Direct Hit on Abaco Islands

The eye of Category 5  Hurricane Dorian was directly over the Abaco Islands as of the National Hurricane Center’s (NHC) 2:00 pm EDT advisory and is now heading towards Grand Bahama Island. The hurricane is located about 185 miles (295 km) east of West Palm Beach, FL. Maximum sustained winds are 185 mph (295 km/h) with gusts over 200 mph. Dorian is moving west at 7 mph.  The central pressure is 911 Mb which continues to lower meaning the storm continues to intensify. This is the fifth Category 5 hurricane sustained in the last five years.

Suomi NPP image of Dorian
Suomi NPP image of Hurricane Dorian showing its well-defined eye as it passed over Dorian at 3:20 am EDT (0720 UTC). Credit: NASA/NOAA/UWM-SSEC-CIMSS/William Straka III

NASA and NOAA satellites flew over the storm after the NHC’s 2:00 am EDT (0600Z) advisory each highlighting unique features within the storm. At 3:20 am EDT (0720 UTC) NASA’s Suomi NPP satellite caught Dorian (above) on the east side of the scan in the Day Night band but due to the angle did not yield as many features due to noise at the edge of the scan, however, the well-defined eye can still be seen along with the tropospheric convective gravity waves flowing away from the storm.

NOAA-20’s VIIRS instrument provides this image in its Day Night band of Hurricane Dorian at 2:30 am EDT on Sep. 01, 2019. Credit: NASA/NOAA/UWM-SSEC-CIMSS/William Straka III

A slower westward motion should continue for the next day or two, followed by a gradual turn toward the northwest. On this track, the core of
extremely dangerous Hurricane Dorian will continue to pound Great Abaco today and the move near or over Grand Bahama Island tonight and Monday. The hurricane should move closer to the Florida east coast late Monday through Tuesday night.

Hurricane-force winds extend outward up to 45 miles (75 km) from the center and tropical-storm-force winds extend outward up to 140 miles (220 km). The eye of the hurricane is now 25 nautical miles across.

For continuous coverage visit: https://www.nhc.noaa.gov

By Lynn Jenner
NASA Goddard Space Flight Center

Dorian – Atlantic Ocean

Sep. 01, 2019 – Update #2 – 10:35 am EDT – Dorian Intensifying Again With Winds Picking Up Speed

The National Hurricane Center (NHC) put out another update advisory at 9:30 am EDT on Sep. 01, 2019 as Hurricane Dorian intensified again.

Data from an Air Force Reserve Hurricane Hunter aircraft indicate
that Dorian has continued to intensify, and now has maximum
sustained winds near 175 mph (280 km/h) and wind gusts over 200 mph.  Storm surge of 15 to 20 feet above normal tides with higher destructive waves.  There is a minimum central pressure of 922 mb (27.23 inches).

The eyewall of catastrophic Hurricane Dorian is currently reaching
the Abaco Islands. This is a life-threatening situation. Residents
there should take immediate shelter.  The NHC urges: “Do not venture into the eye if it passes over your location. These hazards will cause extreme destruction in the affected areas. and will continue for several hours.”

The NOAA-20 satellite observed Dorian’s continued intensification in this satellite image which was captured on Sep. 01, 2019 at 2:30 am EDT.

GPM image of Dorian
NOAA-20 flew over Dorian not quite looking straight down. As with previous nights, the infrared imagery continued to show convective gravity waves and a well-defined eye. However, unlike previous nights, the cirrus blowoff was not present. Rather it was replaced by the classic “buzzsaw” type cloud commonly seen in very intense tropical storms. This Day Night Band imagery continues to show the structure of Dorian quite well along with mesospheric gravity waves being flung far away from the storm as well as a lone lightning streak well on the southern part of the storm. Credit: NASA/NOAA/UWM-SSEC-CIMSS/William Straka III

For continuing coverage of the storm visit: https://www.nhc.noaa.gov

By Lynn Jenner
NASA Goddard Space Flight Center

Dorian – Atlantic Ocean

Sept. 01, 2019 – Update #1 – NASA Satellites Monitor Progress as Hurricane Dorian Reaches Dangerous Category 5 Status

The National Hurricane Center’s (NHC) 8:00 am EDT advisory reports that Hurricane Dorian has reached Category 5 status on the Saffir-Simpson Hurricane Wind scale. Data from an Air Force Hurricane Hunter plane which just penetrated the eye of Dorian indicate that the maximum sustained winds have increased to near 160 mph (260 km/h) with higher gusts. Devastating hurricane conditions are expected in the Abacos Islands very soon and these conditions will spread across Grand Bahama Island later today.

GPM image of Dorian
As of Saturday, August 31, Hurricane Dorian’s (still a Category 4 storm at the time) rain field had changed. During its early days near Puerto Rico, Dorian’s inner-core rain rate had peaked once every 24 hours, but during the most recent two days, Dorian’s rain rate has been persistently heavy. Heavy precipitation under the eyewall suggests that a great deal of energy is being released in the atmosphere, which is the fuel that allows a hurricane to sustain or increase its wind intensity. The graphic also shows the distance that tropical-storm force (39 mph) winds extend from Hurricane Dorian’s low-pressure center, as reported by the National Hurricane Center. The symbols H and TS represent a hurricane of various Saffir-Simpson categories or a tropical storm, respectively. Visualization by NASA Goddard.

As of Saturday, August 31, Hurricane Dorian’s rain field had changed. During its early days near Puerto Rico, Dorian’s inner-core rain rate had peaked once every 24 hours, but during the most recent two days, Dorian’s rain rate has been persistently heavy. Heavy precipitation under the eyewall suggests that a great deal of energy is being released in the atmosphere,
which is the fuel that allows a hurricane to sustain or increase its wind intensity.

These rain estimates come from the Global Precipitation Measurement mission (GPM)’s NASA IMERG algorithm, which combines observations from a fleet of satellites, in near-realtime, to provide global estimates of precipitation every 30 minutes. The storm-total rainfall at a particular location varies with the forward speed of the hurricane, with the size of the hurricane’s wind field, and with how vigorous the updrafts are inside of the hurricane’s eyewall.

NASA’s Aqua satellite also was providing scientists with data about the storm when it passed overhead on Aug. 31, 2019.

AIRS image of Dorian on Aug. 31
On Aug. 31 at 2:17a.m. EDT (0617 UTC), the AIRS instrument aboard NASA’s Aqua satellite analyzed cloud top temperatures of Tropical Storm Dorian 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).  The area of very cold temperatures is extremely large around the eye indicating greater intensity. Credit: NASA JPL/Heidar Thrastarson

This image, captured by NASA’s Aqua satellite at 2:17 am EDT the morning of the 31st, shows incredibly cold temperatures in the cloudtops of the storm.  The area of purple, the coldest temperatures, extends out widely from the very distinct eye of the hurricane. The stronger the storms, the higher they extend into the troposphere, and the colder the cloud temperatures become so the AIRS instrument gives a good picture to scientists of the strength of the storm.

The NHC has reported that hurricane-force winds extend outward up to 30 miles (45 km) from the center, and tropical-storm-force winds extend outward up to 105 miles (165 km). Elbow Cay in the Abaco Islands just reported winds of 35 mph (56 km/h).  The minimum central pressure just measured by an Air Force plane has dropped to 927 mb (27.37 inches).

The following information is directly from the National Hurricane Center’s 8:00 am EDT advisory:

“A Hurricane Warning is in effect for…* Northwestern Bahamas excluding Andros Island

A Hurricane Watch is in effect for…* Andros Island

A Tropical Storm Warning is in effect for…* North of Deerfield Beach to Sebastian Inlet

A Tropical Storm Watch is in effect for…* North of Golden Beach to Deerfield Beach

A Hurricane Warning means that hurricane conditions are expected
somewhere within the warning area. Preparations to protect life and
property should be rushed to completion.

A Hurricane Watch means that hurricane conditions are possible within the watch area.

A Tropical Storm Warning means that tropical storm conditions re expected within the warning area within 36 hours.

A Tropical Storm Watch means that tropical storm conditions are possible within the watch area, generally within 48 hours.

Interests elsewhere in southern and central Florida should continue to monitor the progress of Dorian. Additional watches or warnings may be required for portions of the east coast of Florida today.

For storm information specific to your area in the United States, including possible inland watches and warnings, please monitor products issued by your local National Weather Service forecast office. For storm information specific to your area outside of the United States, please monitor products issued by your national meteorological service.

Tropical storm conditions are expected within the tropical storm warning area on Monday.

Tropical storm conditions are possible within the tropical storm watch area by Monday night.

STORM SURGE: A life-threatening storm surge will raise water levels by as much as 15 to 20 feet above normal tide levels in areas of onshore winds on the Abaco Islands and Grand Bahama Island. Near the coast, the surge will be accompanied by large and destructive waves.

RAINFALL: Dorian is expected to produce the following rainfall totals through late this week:

Northwestern Bahamas…12 to 24 inches, isolated 30 inches.
Coastal Carolinas…5 to 10 inches, isolated 15 inches.
Central Bahamas and the Atlantic Coast from the Florida peninsula
through Georgia…2 to 4 inches, isolated 6 inches.

This rainfall may cause life-threatening flash floods.

SURF: Large swells will affect the east-facing shores of the Bahamas, the Florida east coast, and the southeastern United States coast during the next few days. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office.”

For further information on the storm visit: https://www.nhc.noaa.gov

By Lynn Jenner
NASA Goddard Space Flight Center

Dorian – Atlantic Ocean

Aug. 31, 2019 – Update #2 – NASA Watches as Category 4 Hurricane Dorian Still Heads for Northwestern Bahamas

The latest National Hurricane Center (NHC) advisory has Hurricane Dorian on a collision course with the northwestern Bahamas sometime on Sunday and moving near the Florida east coast late Monday into Tuesday.  Still a Category 4 some fluctuations in intensity are likely within the storm, but Dorian is expected to remain a powerful hurricane during the next
few days.

NOAA-NASA’s Suomi NPP satellite, GCOM-W1 and NOAA-20 all passed over Dorian in that order, right around the 2:00 am EDT NHC advisory, each observing unique features.

Suomi NPP image of Dorian
At 1:58 am EDT (0558 UTC) Suomi NPP caught Dorian on the west side of the scan showing a well-defined eye that can be easily seen along with different cloud bands as well as a lone lightning strike within the storm in the southern portion.  Infrared imagery also spotted tropospheric convective gravity waves flowing away from the intense storm. Credit: NASA/NOAA/UWM-SSEC-CIMSS/William Straka III

At 1:58 am EDT (0558 UTC) on Aug. 31, 2019, Suomi NPP caught Dorian on the west side of the scan showing a well-defined eye that can be easily seen along with different cloud bands.  A lone lightning strike is seen within the storm in the southern portion. Infrared imagery also spotted tropospheric convective gravity waves flowing away from the intense storm.  The NHC remarked at 2:00 pm EDT (1800 UTC) that Hurricane Dorian was exhibiting a very distinct eye 15 nautical miles across.

NOAA-20 image of Dorian
At 2:48 am EDT (0648 UTC), NOAA-20 flew over Dorian close to top down. The infrared imagery continues to show the convection gravity waves consistent with an intense storm.  Lightning is also seen in this image as well as the mesospheric gravity waves of a powerful storm. Credit: NASA/NOAA/UWM-SSEC-CIMSS/William Straka III

Roughly 50 minutes later at 2:48 am EDT (0648 UTC), NOAA-20 flew over Dorian close to top-down. The infrared imagery continues to show convection gravity waves consistent with an intense storm.  The successive passes showed the rotation of the storm at high resolution. The zoomed out Day Night Band imagery showed the structure of Dorian quite well, even though there was no moonlight present, along with mesospheric gravity waves being flung far away from the storm.

NOAA-20 shows the distinctive well-defined eye of a powerful Category 4 hurricane in this image taken at 2:48 am EDT on August 31, 2019. Credit: NASA/NOAA/UWM-SSEC-CIMSS/William Straka III

It is only when a storm is well developed that the refined eye appears giving forecasters an idea of the center of circulation.  Aircraft and dropsonde information also provide crucial information about the surrounding environment of the storm, albeit at select points within the storm.

 

GCOM - W1 satellite catches the eye of the Dorian and a possible eyewall replacement.
The Global Change Observation Mission – Water “Shizuku” satellite’s AMSR2 instrument captured this image of Dorian’s well-defined eye as well as hints of maybe a secondary set of convection about halfway around the inner eye, possibly catching one of the eyewall replacement cycles. Credit: NASA/NOAA/UWM-SSEC-CIMSS/William Straka III

At 2:23 am EDT the AMSR2 instrument on the Global Change Observation Mission – Water “Shizuku” satellite (GCOM-W1), a Japan Aerospace Exploration Agency satellite, caught Dorian on the western side of the scan and the well-defined eye was evident as well as hints of perhaps a secondary set of convection about halfway around the inner eye. While nothing was mentioned about an eyewall replacement occurring in the 5am NHC advisory it is possible that the Advanced Microwave Scanning Radiometer 2 (AMSR2) caught one of the eyewall replacement cycles.

Dorian is currently located latitude 26.1N and longitude 73.9W about 205 miles (325 hkm) east of Great Abaco in the Bahamas and about 385 miles (625 km) east of West Palm Beach, FL.  The Air Force reconnaissance plane recorded the maximum sustained winds remain consistent at 150 mph (240 km/h).  As a point of comparison Category 5 strength winds begin at 157 mph (251 km/h). Hurricane Dorian’s movement has slowed to 8 mph (13 km/h) which gives this storm more time over open warm waters to continue to gain strength.  The barometric pressure is steady at 945 mb.

Hurricane-force winds extend outward up to 30 miles (45 km) from the center and tropical-storm-force winds extend outward up to 115 miles (185 km).

For more information on the storm visit:  https://www.nhc.noaa.gov

By Lynn Jenner
NASA Goddard Space Flight Center

Dorian – Atlantic Ocean

Aug. 31, 2019 – Update #1 – NASA Satellites Following Hurricane Dorian On Its Trek Westward

On Friday evening of Aug. 30, Dorian attained Category 4 status on the Saffir-Simpson Hurricane Wind Scale which means the storm is packing 130 – 156 mph (209-251 km/h) winds.  The second change in the storm was the turn it took during the nighttime hours which now has the storm potentially not making direct landfall on Florida but rather Georgia and the Carolinas.  However, it should be noted that this track could change once again.  According to the National Hurricane Center (NHC): “Significant impacts could also occur even if the center of Dorian stays offshore. With the change in the forecast, the risk of strong winds and life-threatening storm surge is increasing along the coasts of Georgia and South Carolina during the middle of next week.”

AIRS image of Dorian
On Aug. 30 at 2:11 p.m. EDT (1811 UTC), the AIRS instrument aboard NASA’s Aqua satellite analyzed cloud top temperatures of Tropical Storm Dorian 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). Credit: NASA JPL/Heidar Thrastarson

NASA’s Aqua satellite was on duty measuring the cloudtop temperatures in the powerful storm on Aug. 30, 2019. These very cold clouds with temperatures as cold or colder than minus 63 degrees Fahrenheit are tightly wound in a large area around the very well defined eye of the storm. Cloud top temperatures that cold indicate strong storms with the potential to generate heavy rainfall.

Worldview image of Dorian on Aug. 30, 2019.
NOAA-NASA’s Suomi NPP satellite captured this visible light image of Hurricane Dorian on Aug. 30, 2019 as it was just north of Turks and Caicos and heading towards the northwestern Bahamas. Credit: NASA Worldview, Earth Observing System Data and Information System (EOSDIS).

NASA’s Earth Observing System Data and Information System (EOSDIS) Worldview application provides the capability to interactively browse over 700 global, full-resolution satellite imagery layers and then download the underlying data. Many of the available imagery layers are updated within three hours of observation, essentially showing the entire Earth as it looks “right now.” This natural-color image was collected by NOAA-NASA’s Suomi NPP satellite on Aug. 30, 2019.

The NHC’s analysis of the storm which was released it 8am on Aug. 31, 2019 has Dorian gaining strength and moving westward.  Its current location is latitude 25.8N and longitude 73.0W which is about 445 miles (713 km) east of West Palm Beach, FL and 280 miles (450 km) east of the northwestern Bahamas. Its maximum sustained winds are 145 mph (230 km/h) which puts it well into Category 4 status. Dorian is moving west at 12 mph. The barometric pressure inside the storm has dropped to 944 mb.

Hurricane-force winds extend outward up to 30 miles (45 km) from the center and tropical-storm-force winds extend outward up to 105 miles (165 km).

ISS image of Dorian on Aug. 30
The International Space Station captured this stunning image of Hurricane Dorian from space on August 30, 2019. Credit: NASA

A Hurricane Warning is in effect for…
* Northwestern Bahamas excluding Andros Island

A Hurricane Watch is in effect for…
* Andros Island

Hurricane conditions are expected in the hurricane warning area across the northwestern Bahamas by Sunday, with tropical storm winds beginning tonight.

The NHC will release its next complete advisory at 11am EDT.  For more information on this storm visit:  https://www.nhc.noaa.gov

By Lynn Jenner
NASA’s Goddard Space Flight Center

Dorian – Atlantic Ocean

Aug. 30, 2019 – Update #3 -NASA Satellites On-Hand As Dorian Becomes a Category 3 Hurricane

As Hurricane Dorian was upgraded to a Category 3 hurricane on the Saffir-Simpson Hurricane Wind Scale, NASA’s fleet of satellites were gathering data during the day to assist weather forecasters and scientists.  At 2:oo pm EDT the National Hurricane Center (NHC) posted a supplemental advisory. NHC reports that “extremely dangerous  Hurricane Dorian poses a significant threat to Florida and the northwestern Bahamas.  The Hurricane Hunter plane finds Dorian is now a major hurricane.”

IMERG estimates Hurricane Dorian's rain
As of early on August 30, Hurricane Dorian has been producing 2 to 6 inches of rain along the path of its inner core for several days. This estimate come from the NASA IMERG algorithm, which combines observations from a fleet of satellites, in near-realtime, to provide global estimates of precipitation every 30 minutes. The storm-total rainfall at a particular location varies with the
forward speed of the hurricane, with the size of the hurricane’s wind field, and with how vigorous the updrafts are in the hurricane’s eyewall. The graphic also shows the distance that tropical-storm force (39 mph) winds extend from the Hurricane Dorians low-pressure center, as reported by the National Hurricane Center. The symbols H2, H1, and TS represent category 2 hurricane, category 1 hurricane, and tropical storm, respectively. Visualization by NASA Goddard.

NASA’s Global Precipitation Measurement mission satellite uses its IMERG algorithm with data from a fleet of satellites to provide global estimates of the precipitation within the storm every 30 minutes.  This map displays the estimated rainfall accumulation for the region from August 27th – August 30th, prior to Dorian becoming a Category 3 storm.

NOAA-NASA’s Suomi NPP satellite uses its complement of instruments onboard to dissect storms and provide information on many different aspects of the hurricane including storm strength, cloudtop temperature, circulation, and rainfall, among others, within the structure of the storm.  The next three images are all from the Suomi NPP satellite and its instruments which help scientists figure out the intensity of the storm and help predict where it will ultimately end up.

Suomi NPP image of Dorian
NASA/NOAA’s Suomi NPP satellite was in an ideal position for observing Dorian at 0617 UTC (2:17 am EDT) at an almost nadir view (right over the storm). The infrared imagery showed a somewhat circular storm, though a bit lopsided. However, the convection was strong enough to result in several overshooting tops and tropospheric gravity waves are atmospheric waves (in this observation from the troposphere) that are produced by strong thunderstorms near the eye and radiate outward in expanding spirals giving forecasters and scientists a good indicator of the strength of the storm. This top-down view of Dorian allowed the microwave sounder to observe the inner structure of the storm. Credit: NASA/NOAA/UWM-SSEC-CIMSS/William Straka III

Hurricane Dorian is currently at latitude 24.8N and longitude 70.3W which is about 445 miles (715 km) east of the northwestern Bahamas and about 625 miles (1005 km) east of West Palm Beach, FL.   The NHC forecast is: “A slower west-northwestward to westward motion should begin tonight and continue into early next week. On this track, the core of Dorian should move over the Atlantic well north of the southeastern and central Bahamas today and tomorrow, be near or over the northwestern Bahamas on Sunday, and be near the Florida peninsula late Monday.”

Suomi NPP ATMS instrument shows the circulation of Dorian.
From the 88.2GHz BT, the circulation of the storm is easily seen with the convection showing colder temperatures. Credit: NASA/NOAA/UWM-SSEC-CIMSS/William Straka III

Currently the storm’s maximum sustained winds are 115 mph (185 km/h) with higher gusts, and is moving northwest at 10 mph (17 km/h).  Hurricane-force winds extend outward up to 25 miles (35 km) from the center and tropical-storm-force winds extend outward up to 105 miles (165 km). The minimum central pressure is 970 mb.

Suomi NPP MISR instrument showing rainfall in Dorian
Suomi NPP’s MiRS instrument provided the rain rate and also showed the rain wrapping into the circulation center. Credit: NASA/NOAA/UWM-SSEC-CIMSS/William Straka III

The summary of watches and warnings in effect have not changed since the last NHC update at 11:00 am EDT.

For more information and updates, visit:  https://www.nhc.noaa.gov

By Lynn Jenner
NASA’s Goddard Space Flight Center

Dorian – Atlantic Ocean

Aug. 30, 2019 – Update #2 – Hurricane Dorian Marching Slowly Across Atlantic

The National Hurricane Center (NHC) in Miami reports that an Air Force plane is finding Dorian a “little stronger” as of the 8:00am EDT advisory put out today, Aug. 30, 2019.  Data from an Air Force Reserve reconnaissance aircraft indicate that maximum sustained winds have increased to near 110 mph (175 km/h) with higher gusts. That is in keeping with what weather forecasters are predicting for the storm.

AIRS image of Dorian from 8/30/19.
On Aug. 29 at 1:29 p.m. EDT (1729 UTC), the AIRS instrument aboard NASA’s Aqua satellite analyzed cloud top temperatures of Tropical Storm Dorian 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). Credit: NASA JPL/Heidar Thrastarson

On Aug. 29, 2019, NASA’s Aqua satellite captured this infrared image with the AIRS instrument which analyzed cloud top temperatures in the storm.  The coldest temperatures AIRS found were in the center of the storm where the strongest thunderstorms are found.  These storms were as cold as or colder than minus 63 degrees Fahrenheit (minus 53 degrees Celsius).  NASA research has found that cloud top temperatures that cold indicate strong storms with the potential to generate heavy rainfall.

At 8:00 am EDT (1200 UTC), the NHC reported that “the the center of Hurricane Dorian was located near latitude 24.2 North, longitude 69.4 West. Dorian is moving toward the northwest near 12 mph (19 km/h), and this motion is expected to continue through today. A slower west-northwestward to westward motion is forecast to begin tonight and continue through the weekend. On this track, Dorian should move over the Atlantic well east of the southeastern and central Bahamas today, approach
the northwestern Bahamas Saturday, and move near or over portions of
the northwestern Bahamas on Sunday.”

Dorian is expected to strengthen during the next few days, and become a major hurricane later today (Aug. 30). Dorian is likely to remain an extremely dangerous hurricane while it moves near the northwestern Bahamas and approaches the Florida peninsula through the weekend.

Currently hurricane-force winds extend outward up to 25 miles (35 km) from the center, and tropical-storm-force winds extend outward up to 105
miles (165 km).  Yesterday the barometric pressure inside the storm was 991 mb.  Today the minimum central pressure just reported by the Air Force reconnaissance plane was 972 mb (28.70 inches).  The lower the barometric pressure in hurricanes, the higher the wind speeds— and the more dangerous the storm.

Hurricane conditions are possible within the watch area by Sunday, with tropical storm conditions possible by Saturday night or Sunday morning.

A life-threatening storm surge will raise water levels by as much as 10 to 15 feet above normal tide levels in areas of onshore winds in the northwestern Bahamas. Near the coast the surge will be accompanied by large and destructive waves.

Dorian is expected to produce the following rainfall accumulations this weekend into the middle of next week:

Northwestern Bahamas and coastal sections of the Southeast United States…6 to 12 inches, isolated 15 inches.
Central Bahamas…1 to 2 inches, isolated 4 inches.

This rainfall may cause life-threatening flash floods.

Swells are likely to begin affecting the east-facing shores of the Bahamas and the southeastern United States coast during the next few days. These swells are likely to cause life-threatening surf and rip current conditions.

For updated forecasts, visit NOAA’s NHC: www.nhc.noaa.gov

By Lynn Jenner
NASA’s Goddard Space Flight Center