July 2020 – Page 2 – Hurricane And Typhoon Updates

Hanna (was TD08) – Gulf of Mexico

July 25, 2020 – NASA Sees Hanna Strengthen into First Atlantic Hurricane of 2020

NASA satellite imagery revealed powerful thunderstorms fueled the intensification of Hanna into a hurricane along the Texas coast. Hanna has become the first hurricane of the Atlantic Ocean hurricane season, and has triggered warnings along the Texas coast today, July 25, 2020.

Aqua image of Hanna — On July 25 at 3:50 a.m. EDT (0750 UTC) the MODIS instrument that flies aboard NASA’s Aqua satellite revealed very powerful thunderstorms (yellow) around Hanna’s center where cloud top temperatures were as cold as minus 80 degrees Fahrenheit (minus 62.2 Celsius), indicating the storm had strengthened.
Credits: NASA/NRL

Warnings in Effect

The National Hurricane Center posted warnings on July 25 for areas of the Texas coast as Hanna approaches for landfall. A Storm Surge Warning is in effect from Port Mansfield to Sargent, Texas. A Hurricane Warning is in effect from Port Mansfield to Mesquite Bay, Texas.

A Tropical Storm Warning is in effect from Barra el Mezquita, Mexico to Port Mansfield, Texas and for Mesquite Bay to High Island, Texas.

NASA Infrared Data Shows Hanna Strengthened

On July 25 at 3:50 a.m. EDT (0750 UTC), the Moderate Resolution Imaging Spectroradiometer or MODIS instrument that flies aboard NASA’s Aqua satellite used infrared light to analyze the strength of storms within Hanna. MODIS revealed that cloud tops in very powerful thunderstorms around Hanna’s center had become colder since the previous day. That means the uplift in the storm was stronger and pushed the cloud tops higher into the troposphere. Cloud top temperatures in those areas were as cold as minus 80 degrees Fahrenheit (minus 62.2 Celsius), indicating the storm had strengthened. NASA research has found that cloud top temperatures that cold indicate strong storms with the potential to generate heavy rainfall.

Tropical cyclones are made of up hundreds of thunderstorms, and infrared data can show where the strongest storms are located. That is because infrared data provides temperature information, and the strongest thunderstorms that reach highest into the atmosphere have the coldest cloud top temperatures. NASA researches these storms to determine how they rapidly intensify, develop and behave.

Heavy Rainfall, Storm Surge, Hurricane-force Winds, Isolated Tornadoes

The National Hurricane Center forecast warns about storm surge up to 5 feet in various areas, hurricane conditions, isolated tornadoes, heavy rainfall, flooding, and dangerous ocean swells from Texas to Louisiana.

Infrared imagery from NASA shows the capability of Hurricane Hanna to generate heavy rainfall, and the National Hurricane Center has included that rainfall potential in their forecast. NHC said, “Hanna is expected to produce 6 to 12 inches of rain with isolated maximum totals of 18 inches through Sunday night in south Texas and into the Mexican states of Coahuila, Nuevo Leon, and northern Tamaulipas. This rain may result in life-threatening flash flooding, rapid rises on small streams, and isolated minor to moderate river flooding in south Texas.”

Hanna’s Status on Saturday, July 25

At 8 a.m. EDT (1200 UTC), the center of Hurricane Hanna was located by reconnaissance aircraft and NOAA Doppler weather radars near latitude 27.1 degrees north and longitude 96.0 degrees west. Hanna is just 90 miles (150 km) east-northeast of Port Mansfield, Texas. Hanna is moving toward the west near 9 mph (15 km), and this motion should continue through this morning. A gradual turn toward the west-southwest is expected by tonight and that motion should continue through Sunday.

Data from the reconnaissance aircraft and Doppler weather radars indicate that maximum sustained winds have increased to near 75 mph (120 kph) with higher gusts. Data from the NOAA Hurricane Hunter aircraft indicate that the minimum central pressure is 982 millibars.

Additional strengthening is forecast before Hanna makes landfall later today. Rapid weakening is expected after Hanna moves inland. On the forecast track, the center of Hanna should make landfall along the Texas coast within the hurricane warning area this afternoon or early this evening.

Typhoons/hurricanes are the most powerful weather events on Earth. NASA’s expertise in space and scientific exploration contributes to essential services provided to the American people by other federal agencies, such as hurricane weather forecasting.

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

For previous Hanna updates visit: https://blogs.nasa.gov/hurricanes/tag/td08-2020/

By Rob Gutro
NASA’s Goddard Space Flight Center

Douglas – Eastern Pacific Ocean

July 26, 2020 – NASA-NOAA’s Suomi NPP Provides Night-Time Analysis of Hurricane Douglas

NASA-NOAA’s Suomi NPP satellite provided forecasters with various nighttime views of Hurricane Douglas as it approaches Hawaii. The various imagery provided valuable data on the storm’s structure and strength.

Infrared image of Douglas — On July 25 at 7:36 a.m. EDT (1:36 a.m. HST/1136 UTC), this infrared image of Hurricane Douglas taken from NASA-NOAA’s Suomi NPP satellite showed a closed circulation and a relatively compact storm. Some warmer air was also being pulled into the storm. Satellite data also showed an exposed circulation on the southeast side. Credit: NASA/NOAA/UWM-CIMSS, William Straka III

On July 26, NOAA’s Central Pacific Hurricane Center or CPHC warned that “Dangerous Hurricane Douglas is closing in on the Hawaiian Islands.”

Many Warnings in Place for Hawaii

On Sunday, July 26, 2020 warnings and watches pepper Hawaii as Hurricane Douglas approaches. A Hurricane Warning is in effect for Oahu, Kauai County, including the islands of Kauai and Niihau. A Tropical Storm Warning is in effect for Hawaii County, Maui County, including the islands of Maui, Lanai, Molokai and Kahoolawe. In addition, a Hurricane Watch is in effect for Hawaii County, Maui County, including the islands of Maui, Lanai, Molokai and Kahoolawe. A Tropical Storm Watch is in effect for portions of the Papahanaumokuakea Marine National Monument from Nihoa to French Frigate Shoals.

What NASA-NOAA’s Suomi NPP Satellite Showed

On July 25 at 5 a.m. EDT (0900 UTC) Hurricane Douglas was a strong Category 2 storm with winds near 110 mph. NOAA’s CPHC mentioned that Douglas had a degraded satellite presentation. Two and one half hours later, NASA-NOAA’s Suomi NPP satellite passed over Douglas and provided a nighttime view of the storm as well as an infrared view.

In the nighttime view, the waxing crescent moon (27% illumination) was still low enough with the features in the Suomi NPP Day Night Band were illuminated by airglow. “There continued to be no mesospheric waves, which is not surprising given the gradual degradation of the storm,” said William Straka III, Researcher at the University of Wisconsin – Madison, Space Science and Engineering Center (SSEC), Cooperative Institute for Meteorological Satellite Studies (CIMSS). Straka provided the nighttime and infrared images.

Nighttime view of Douglas — The nighttime view of Hurricane Douglas is seen from NASA-NOAA’s Suomi NPP on July 25 at 7:36 a.m. EDT (1:36 a.m. HST/1136 UTC). There continued to be no mesospheric waves, which is not surprising given the gradual degradation of the storm. Credit: NASA/NOAA/UWM-CIMSS, William Straka III

The high-resolution infrared imagery from Suomi NPPs Visible Infrared Imaging Radiometer Suite (VIIRS) instrument showed a closed circulation and a relatively compact storm. The VIIRS instrument cloud top temperatures around the eye were as cold as 210 Kelvin (minus 81.6 degrees Fahrenheit (minus 63.1 Celsius), indicating powerful storms.

Straka noted, “Satellite imagery also seemed to indicate some warmer air being pulled in to the storm. This was supported by the Advanced Microwave Scanning Radiometer 2 (AMSR2) instrument (that also flies aboard Suomi NPP) data taken roughly 20 minutes earlier, which also seemed to show an exposed circulation on the southeast side.”

Satellite Imagery on July 26, 2020

CPHC Hurricane forecaster Thomas Birchard said in the July 26 discussion, “Worth noting is that the data also indicate that the low-level center is south of the center that is seen in conventional satellite imagery. Recent microwave images confirm that the cyclone is tilted to the north with height, due to southerly vertical wind shear. Despite the vertical wind shear, Douglas is expected to only slowly weaken as it comes dangerously close to the Hawaiian Islands.”

Hurricane Douglas’ Status on Sunday, July 26, 2020

NOAA’s CPHC noted at 8 a.m. EDT (2 a.m. HST/1200 UTC) on July 26, the center of Hurricane Douglas was located by Hurricane Hunter aircraft near latitude 20.5 north, longitude 153.6 west. That puts Douglas’ center about 190 miles (300 km) east of Kahului, Hawaii and 285 miles (460 km) east of Honolulu, Hawaii.

Douglas is moving toward the west-northwest near 16 mph (26 kph), and this general motion is expected to continue for the next couple of days. The estimated minimum central pressure is 983 millibars. Maximum sustained winds are near 90 mph (150 kph) with higher gusts.

Forecast for Douglas

NOAA’s CPHC forecast calls for “Some slow weakening is forecast during the next 48 hours, but Douglas is expected to remain near hurricane intensity as it passes near, or over, the islands. On the forecast track, Hurricane Douglas will pass dangerously close to the main Hawaiian Islands later today.”

For more than five decades, NASA has used the vantage point of space to understand and explore our home planet, improve lives and safeguard our future. NASA brings together technology, science, and unique global Earth observations to provide societal benefits and strengthen our nation. Advancing knowledge of our home planet contributes directly to America’s leadership in space and scientific exploration.

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

By Rob Gutro
NASA’s Goddard Space Flight Center

Gonzalo – Atlantic Ocean

July 26, 2020 – NASA Imagery Catches Tropical Storm Gonzalo Degenerating into a Tropical Wave

After Tropical Storm Gonzalo passed over Trinidad and Tobago, it weakened to a remnant low pressure area. NASA-NOAA’s Suomi NPP satellite passed overhead from space and snapped a visible image that revealed the storm was transitioning into a tropical wave.

Suomi NPP image of Gonzalo — NASA-NOAA’s Suomi NPP satellite passed over the North Atlantic Ocean during the afternoon on July 25 and captured a visible image of Gonzalo after it moved past Trinidad and Tobago and degenerated into a tropical wave. Credit: NASA Worldview, Earth Observing System Data and Information System (EOSDIS).

The Republic of Trinidad and Tobago is a dual island nation and the southernmost island country in the Caribbean. Trinidad Island is about 7 miles (11 km) off the northeastern coast of Venezuela.

NASA-NOAA Satellite Imagery Reveals No Circulation Center

The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard Suomi NPP provided a visible image of the Gonzalo on July 25 after it passed Trinidad and Tobago. Satellite data showed that it was opening up into a tropical wave. By 5 p.m. EDT, satellite data showed that Gonzalo’s structure had degraded. By that time there was no clear evidence of a well-defined center in visible imagery. It appeared that the system has opened into a tropical wave. A tropical wave is an elongated area of low pressure that stretches from north to south.

Gonzalo Going, Going…

The final advisory on Gonzalo was issued at 5 p.m. EDT on July 25 after it passed Trinidad and Tobago and weakened to a remnant low-pressure area. At 5 p.m. EDT (2100 UTC), the remnants of Gonzalo were located near latitude 11.0 degrees north and longitude 63.0 degrees west. That was about 125 miles (195 km) west-northwest of Trinidad. Maximum sustained winds are near 35 mph (55 kph) with higher gusts.

On Sunday, July 26, the remnants of Gonzalo were classified as a tropical wave currently over the eastern Caribbean. Tropical squalls associated with the remnants of Gonzalo will continue to move westward for the next couple of days.

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

By Rob Gutro
NASA’s Goddard Space Flight Center

Douglas – Eastern Pacific Ocean

July 25, 2020 – NASA’s Aqua Satellite Examines Hurricane Douglas as it Nears Hawaii

NASA’s Aqua satellite provided a visible image of Hurricane Douglas is it continued on its track toward Hawaii. The storm is now a Category 2 hurricane and warnings were posted on July 25, 2020 as the storm approaches.

Aqua image of Douglas — On July 24 at 1:30 p.m. EDT, the MODIS instrument aboard NASA’s Aqua satellite provided a visible image of Hurricane Douglas as it continued on a track toward the Hawaiian Islands. The image showed a clear eye with a circular structure.
Credits: NASA Worldview, Earth Observing System Data and Information System (EOSDIS)

Warnings Up for Hawaii

The Central Pacific Hurricane Center has posted warnings for Douglas.

A Tropical Storm Warning is in effect for Hawaii County, Maui County, including the islands of Maui, Lanai, Molokai and Kahoolawe. A Hurricane Watch is in effect for Hawaii County, Maui County, including the islands of Maui, Lanai, Molokai and Kahoolawe and Oahu.

On July 24 at 1:30 p.m. EDT, the Moderate Resolution Imaging Spectroradiometer or MODIS instrument aboard NASA’s Aqua satellite provided a visible image of Douglas. Hurricane Douglas maintained its eye and structure as it continued moving west through the Central Pacific Ocean and toward Hawaii.

Status of Hurricane Douglas on July 25

At 8 a.m. EDT (2 a.m.’s/1200 UTC), on July 25, NOAA’s Central Pacific Hurricane Center said the center of Hurricane Douglas was located near latitude 18.7 degrees north and longitude 147.7 degrees west. That is about 485 miles (780 km) east of Hilo, Hawaii.

Douglas is moving toward the west-northwest near 18 mph (30 km/h). This motion is expected to continue through Saturday, followed by a slight decrease in forward speed and a turn toward the west. The estimated minimum central pressure is 973 millibars. Maximum sustained winds are near 110 mph (175 kph) with higher gusts. Douglas is a category 2 hurricane on the Saffir-Simpson Hurricane Wind Scale.

Douglas’ Forecast Track

Gradual weakening is expected to continue through the weekend. However, Douglas is still forecast to be near hurricane strength when it nears the islands. On the forecast track, Douglas will be near the main Hawaiian Islands Saturday night through Sunday night.

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

For past NASA updates on Douglas visit: https://blogs.nasa.gov/hurricanes/tag/douglas-2020/

By Rob Gutro
NASA’s Goddard Space Flight Center

Gonzalo – Atlantic Ocean

July 25, 2020 – NASA Sees a Poorly Organized Tropical Storm Gonzalo Nearing Trinidad and Tobago

Tropical Storm Gonzalo was approaching the southern Windward Islands when NASA-NOAA’s Suomi NPP satellite passed overhead from space and snapped a visible image of the storm. On July 25, 2020, heavy rain from Gonzalo was nearing Trinidad and Tobago and warnings were posted.

The Republic of Trinidad and Tobago is a dual island nation and the southernmost island country in the Caribbean. Trinidad Island is about 7 miles (11 km) off the northeastern coast of Venezuela.

NASA-NOAA Satellite Imagery Shows Poor Organization

The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard Suomi NPP provided a visible image of the Gonzalo on July 24 as it was nearing Trinidad and Tobago, and the southern Windward Islands. Gonzalo appeared poorly organized. Even at 11 p.m. EDT on July 24, although there was an increase in deep convection in association with Gonzalo, data from an Air Force Reserve Hurricane Hunter aircraft continued to show that the tropical cyclone is poorly organized. That did not improve on July 25 as the surface circulation was still poorly defined, and barely closed. That means that little change in intensity is forecast as the cyclone approaches the southern Windward Islands during the afternoon hours on July 25.

Tropical Storm Warning in Effect on July 25

A Tropical Storm Warning is in effect for Tobago, Grenada and its dependencies. Interests elsewhere in the Windward Islands should monitor the progress of this system.

Status of Gonzalo on Saturday, July 25, 2020

At 8 a.m. EDT (1200 UTC), NOAA’s National Hurricane Center or NHC noted the center of Tropical Storm Gonzalo was located near latitude 10.3 degrees north and longitude 59.8 degrees west. That is about 100 miles (165 km) east of Trinidad.

Gonzalo is moving toward the west near 18 mph (30 kph). A general westward to west-northwestward motion is expected for the next couple of days. Maximum sustained winds are near 40 mph (65 kph) with higher gusts. The estimated minimum central pressure is 1009 millibars.

Gonzalo’s Forecast Track

Little change in strength is forecast before Gonzalo reaches the southern Windward Islands later today. On the forecast track, Gonzalo will move across the southern Windward Islands this afternoon or evening and over the southeastern Caribbean Sea on Sunday, July 26. Weakening is expected after Gonzalo moves over the southeastern Caribbean Sea, and the system is forecast to dissipate by Sunday night or Monday.

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

For past NASA updates on Gonzalo visit: https://blogs.nasa.gov/hurricanes/tag/gonzalo-2020/

By Rob Gutro
NASA’s Goddard Space Flight Center

Hanna (was TD08) – Gulf of Mexico

July 24, 2020 – NASA Animation Tracks Tropical Storm Hanna’s Progression

NASA’s Aqua satellite obtained visible imagery as Tropical Storm Hanna formed in the Gulf of Mexico and continued to organize. A new animation from NASA shows how Hanna developed and intensified as it heads toward landfall in Texas this weekend.

Aqua animation of Hanna — This animation of visible imagery from NASA Aqua Satellite shows the development of Tropical Storm Hanna from July 20 to 23. Clouds associated with the low-pressure area were near south Florida and moved west over the Gulf of Mexico where it formed into a depression and further into a tropical storm. Courtesy: NASA Worldview, Earth Observing System Data and Information System (EOSDIS).

NASA Satellite View: Hanna’s Organization

The Moderate Imaging Spectroradiometer or MODIS instrument that flies aboard NASA’s Aqua satellite captured a visible image of Tropical Storm Hanna on July 23 at 1:30 p.m. EDT. The image showed the storm appeared more organized and had a more rounded shape than it did the previous couple of days. That is an indication that the storm was consolidating, organizing and strengthening.

Satellite imagery from the two days before were coupled with the July 23 image and made into an animation using NASA’s Worldview product at NASA’s Goddard Space Flight Center in Greenbelt, Md. That animation showed the clouds associated with the low-pressure area near south Florida and moving west over the Gulf of Mexico where it formed into a depression and further into a tropical storm.

Warnings Posted

On July 24, 2020, the National Hurricane Center posted a Tropical Storm Warning from the mouth of the Rio Grande to San Luis Pass, Texas.

Tropical Storm Hanna on July 24

At 11 a.m. EDT (1500 UTC) on July 24, the National Hurricane Center (NHC) noted the center of Tropical Storm Hanna was located by NOAA reconnaissance aircraft near latitude 27.2 degrees north and longitude 93.2 degrees west. That is 260 miles (420 km) east of Corpus Christi, Texas.

Hanna is moving toward the west-northwest near 9 mph (15 kph), and this motion should continue today. Maximum sustained winds have increased to near 45 mph (75 kph) with higher gusts. Reports from the NOAA reconnaissance aircraft indicate that the minimum central pressure is 1000 millibars.

Hanna’s Forecast Track

The NHC forecast calls for a turn toward the west is expected tonight, followed by a westward to west-southwestward motion through the weekend. Gradual strengthening is expected until the tropical cyclone makes landfall. On the forecast track, the center of Hanna should make landfall along the Texas coast within the warning area Saturday afternoon or evening. Steady weakening is expected after Hanna moves inland.

About NASA’s Worldview and Aqua Satellite

NASA’s Earth Observing System Data and Information System (EOSDIS) Worldview application provides the capability to interactively browse over 700 global, full-resolution satellite imagery layers and then download the underlying data. Many of the available imagery layers are updated within three hours of observation, essentially showing the entire Earth as it looks “right now.”

NASA’s Aqua satellite is one in a fleet of NASA satellites that provide data for hurricane research.

Tropical cyclones/hurricanes are the most powerful weather events on Earth. NASA’s expertise in space and scientific exploration contributes to essential services provided to the American people by other federal agencies, such as hurricane weather forecasting.

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

By Rob Gutro
NASA’s Goddard Space Flight Center

Douglas – Eastern Pacific Ocean

July 24, 2020 -NASA’s Tracking Hawaii-bound Major Hurricane Douglas

Hurricane Douglas is a major hurricane tracking through the Central Pacific Ocean on a forecast track to Hawaii. NASA’s Aqua satellite used infrared light to identify strongest storms and coldest cloud top temperatures and found them surrounding the eyewall of the powerful hurricane. In addition, images from NASA-NOAA’s Suomi NPP satellite were used to generate an animated track of Douglas’ movement and intensification over four days.

Infrared Data Reveals Powerful Storms

On July 24 at 6:30 a.m. EDT (1030 UTC), the Moderate Resolution Imaging Spectroradiometer or MODIS instrument aboard NASA’s Aqua satellite gathered temperature information about Hurricane Douglas’ cloud tops. Infrared data provides temperature information, and the strongest thunderstorms that reach high into the atmosphere have the coldest cloud top temperatures.

MODIS found the most powerful thunderstorms were in the eyewall, where temperatures were as cold as or colder than minus 70 degrees Fahrenheit (minus 56.6 Celsius). Cloud top temperatures that cold indicate strong storms with the potential to generate heavy rainfall.

Andrew Latto, hurricane specialist at NOAA’s National Hurricane Center noted, “Douglas continues to look impressive in satellite images, with a clear eye and symmetric convection in all quadrants.”

NASA Animates Douglas Through Time

At NASA’s Goddard Space Flight Center in Greenbelt, Md. using the NASA Worldview platform, an animation was created to show Douglas over four days. Using visible imagery from the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard NASA-NOAA’s Suomi NPP satellite, an animation shows the intensification and movement of Hurricane Douglas from July 20 to July 24 in the Eastern Pacific Ocean. Douglas was a Category 4 hurricane on July 24.

Suomi NPP image of Douglas — This animation of visible imagery from the VIIRS instrument aboard NASA-NOAA’s Suomi NPP satellite shows the intensification and movement of Hurricane Douglas from July 20 to July 24 in the Eastern Pacific Ocean. Douglas was a Category 4 hurricane on July 24. Image Courtesy: NASA Worldview, Earth Observing System Data and Information System (EOSDIS).

Douglas’ Status on Friday, July 24, 2020

At 5 a.m. EDT (0900 UTC), the center of Hurricane Douglas was located near latitude 15.7 degrees north and longitude 140.3 degrees west. That is about 1,010 miles (1,630 km) east-southeast of Hilo, Hawaii.

Douglas is moving toward the west-northwest near 18 mph (30 kph), and this motion is expected to continue for the next few days with a gradual decrease in forward speed and a slight turn toward the west.

Maximum sustained winds are near 130 mph (215 kph) with higher gusts. Douglas is a category 4 hurricane on the Saffir-Simpson Hurricane Wind Scale. Hurricane-force winds extend outward up to 30 miles (45 km) from the center and tropical-storm-force winds extend outward up to 90 miles (150 km). The estimated minimum central pressure is 954 millibars.

Gradual weakening is expected to begin today, July 24, and continue through the weekend.

NHC Key Messages

The National Hurricane Center’s key about Douglas is that the storm is expected to move near or over portions of the Hawaiian Islands this weekend, and there is an increasing chance that strong winds, dangerous surf, and heavy rainfall could affect portions of the state beginning Saturday night or Sunday.

About NASA’s Worldview

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

By Rob Gutro
NASA’s Goddard Space Flight Center

Gonzalo – Atlantic Ocean

July 24, 2020 – NASA Water Vapor Data Reveals Tropical Storm Gonzalo’s Soaking Capability

When NASA’s Aqua satellite passed over the North Atlantic Ocean, it gathered water vapor data on Tropical Storm Gonzalo as tropical storm warnings, a tropical storm watch, and hurricane watch were posted.

Aqua image of Gonzalo — On July 24 at 1:35 a.m. EDT (0535 UTC), NASA’s Aqua satellite passed over Tropical Storm Gonzalo in the central Atlantic Ocean. Aqua found highest concentrations of water vapor (brown) and coldest cloud top temperatures were around the center. Credits: NASA/NRL

Water vapor analysis of tropical cyclones tells forecasters how much potential a storm has to develop. Water vapor releases latent heat as it condenses into liquid. That liquid becomes clouds and thunderstorms that make up a tropical cyclone. Temperature is important when trying to understand how strong storms can be. The higher the cloud tops, the colder and stronger the storms.

NASA’s Aqua satellite passed over Tropical Storm Gonzalo on July 24 at 1:35 a.m. EDT (0535 UTC) and the Moderate Resolution Imaging Spectroradiometer or MODIS instrument gathered water vapor content and temperature information. The MODIS image showed highest concentrations of water vapor and coldest cloud top temperatures were around the center of circulation.

MODIS data also showed coldest cloud top temperatures were as cold as or colder than minus 70 degrees Fahrenheit (minus 56.6 degrees Celsius) in those storms. Storms with cloud top temperatures that cold have the capability to produce heavy rainfall.

The National Hurricane Center (NHC) noted that Gonzalo is expected to produce total rain accumulations of 2 to 5 inches, with isolated maximum amounts of 7 inches in Barbados and the Windward Islands tonight (July 24) through Sunday night (July 26). Gonzalo is also expected to produce total rain accumulations of 1 to 2 inches in Trinidad and Tobago. Rainfall in Barbados and the Windward Islands could lead to life-threatening flash floods.

On July 24, a Tropical Storm Warning is in effect for St. Lucia, Barbados, St. Vincent and the Grenadines. A Hurricane Watch is in effect for Barbados, St. Vincent and the Grenadines and a Tropical Storm Watch is in effect for Tobago, Grenada and its dependencies.

At 8 a.m. EDT (1200 UTC), NHC said satellite data indicated that the center of Tropical Storm Gonzalo was located near latitude 10.0 degrees north and longitude 52.8 degrees west. Gonzalo is moving toward the west near 15 mph (24 kph). A westward to west-northwestward motion with an increase in forward speed is expected through the weekend. The estimated minimum central pressure is 1000 millibars. Maximum sustained winds are near 60 mph (95 kph) with higher gusts. Gonzalo is a small tropical cyclone. Tropical-storm-force winds extend outward up to 25 miles (35 km) from the center. Some strengthening is forecast during the next day or two, and there is still a chance that Gonzalo could become a hurricane before reaching the Windward Islands. On the forecast track, the center of Gonzalo will approach the southern Windward Islands tonight and then move across the islands on Saturday (July 25) and over the eastern Caribbean Sea on Sunday (July 26).

NASA’s Aqua satellite is one in a fleet of NASA satellites that provide data for hurricane research.

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

By Rob Gutro
NASA’s Goddard Space Flight Center

TD08 – Gulf of Mexico

July 23, 2020 – NASA Finds Strength in New Gulf Tropical Depression 8

NASA’s Aqua satellite used infrared light to identify the strongest storms and coldest cloud top temperatures in Tropical Depression 8, spinning in the Gulf of Mexico.

Aqua image of TD8 — On July 23 at 4:05 a.m. EDT (0805 UTC), the MODIS instrument aboard NASA’s Aqua satellite gathered temperature information about Tropical Depression 8’s cloud tops. MODIS found several areas of powerful thunderstorms (red) where temperatures were as cold as or colder than minus 70 degrees Fahrenheit (minus 56.6 Celsius). Credit: NASA/NRL

Tropical Depression 8 formed in the Gulf about 530 miles (855 km) east-southeast of Port O’Connor, Texas on July 22 by 11 p.m. EDT.

On July 23 at 4:05 a.m. EDT (0805 UTC), the Moderate Resolution Imaging Spectroradiometer or MODIS instrument aboard NASA’s Aqua satellite analyzed Tropical Depression 8’s cloud tops in infrared light. Infrared data provides temperature information, and the strongest thunderstorms that reach high into the atmosphere have the coldest cloud top temperatures.

Aqua found the most powerful thunderstorms around the center of circulation and areas east of the center, where temperatures were as cold as or colder than minus 70 degrees Fahrenheit (minus 56.6 Celsius). Cloud top temperatures that cold indicate strong storms with the potential to generate heavy rainfall.

At 2 p.m. EDT (1800 UTC) the National Hurricane Center (NHC issued a Tropical Storm Watch from Port Mansfield to High Island, Texas.

At that time, the center of Tropical Depression 8 was located by an Air Force Reserve Hurricane Hunter aircraft near latitude 26.0 degrees north and longitude 90.3 degrees west. That is about 415 miles (665 km) east-southeast of Port O’Connor, Texas. In 15 hours, the storm had moved 115 miles closer to Port O’Connor.

The depression is moving toward the west-northwest near 7 mph (11 kph), and a west-northwestward to westward motion is expected during the next couple of days. Maximum sustained winds are near 35 mph (55 kph) with higher gusts. The latest minimum central pressure reported by the Hurricane Hunter Aircraft is 1008 millibars.

Satellite data at 2 p.m. EDT revealed Tropical Depression 8 is getting better organized, with a better-defined center located near the northeastern end of a broadly curved convective band.

Slow strengthening is expected, and the depression could become a tropical storm during the next 12 to 24 hours. On the forecast track, the center of the depression is expected to move across the northwestern Gulf of Mexico today and Friday and make landfall along the Texas coast on Saturday.

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

By Rob Gutro
NASA’s Goddard Space Flight Center

Gonzalo – Atlantic Ocean

July 23, 2020 – NASA Examines Tropical Storm Gonzalo’s Structural Changes

Visible and microwave imagery from NASA’s Aqua satellite indicated Tropical Storm Gonzalo was slightly less organized than it was on the previous day.

Gonzalo formed in the central North Atlantic Ocean on July 21 and is moving west.

The Moderate Imaging Spectroradiometer or MODIS instrument that flies aboard NASA’s Aqua satellite captured a visible image of Gonzalo late on July 22. The image was created by NASA Worldview at NASA’s Goddard Space Flight Center in Greenbelt, Md. The July 22 visible image of Gonzalo showed a central dense overcast that had become a bit ragged. The banding of thunderstorms seen in earlier images had dissipated.

Microwave imagery captured at 12:53 a.m. EDT (0452 UTC) on July 23 from the Atmospheric Infrared Sounder or AIRS instrument also aboard Aqua, indicated a small convective ring (rising air that forms the thunderstorms that make up a tropical cyclone) was present under the overcast. At 11 a.m. EDT, the National Hurricane Center noted, “Recently-obtained microwave data from overnight shows that Gonzalo’s center is a little farther south than previously estimated.”

AIRS Microwave image of Gonzalo — Microwave imagery captured at 12:53 a.m. EDT (0452 UTC) on July 23 from the AIRS instrument aboard NASA’s Aqua satellite indicated a small convective ring was present under the overcast. Credit: NASA JPL/Heidar Thrastarson

On July 23, NHC forecaster Robbie Berg noted, “The storm’s structure has become a little disheveled since yesterday, with the deep convection losing some organization.”

Hurricane Watch in Effect

On July 23, the National Hurricane Center (NHC) issued a Hurricane Watch for Barbados and St. Vincent and the Grenadines.

Gonzalo’s Status on July 23

The National Hurricane Center (NHC) said at 11 a.m. EDT (1500 UTC), the center of Tropical Storm Gonzalo was located near latitude 9.6 degrees north and longitude 48.3 degrees west. That is about 885 miles (1,425 km) east of the Southern Windward Islands Gonzalo is moving toward the west near 14 mph (22 kph). A westward to west-northwestward motion with an increase in forward speed is expected through the weekend.

Maximum sustained winds are near 65 mph (100 kph) with higher gusts. Gonzalo is a small storm, and tropical-storm-force winds extend outward up to 35 miles (55 km) from the center. The estimated minimum central pressure is 997 millibars.

NHC provided two key messages about the storm:

1. There is an increasing risk of wind and rain impacts from Gonzalo in portions of the southern Windward Islands this weekend; however, there is significant uncertainty in how strong Gonzalo will be when it moves across the islands.

2. Despite the uncertainty in Gonzalo’s future intensity, hurricane conditions are possible across portions of the southern Windward Islands. Hurricane Watches are currently in effect for Barbados and St. Vincent and the Grenadines, and additional watches for other islands could be required later today. Interests in the southern Windward Islands should monitor the progress of Gonzalo and follow any advice given by local officials.

NHC said, “Some strengthening is forecast during the next couple of days, and Gonzalo could become a hurricane tonight or on Friday. On the forecast track, the center of Gonzalo will approach the southern Windward Islands Friday night and move across the islands Saturday and Saturday evening.”

NASA’s Aqua satellite is one in a fleet of NASA satellites that provide data for hurricane research.

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

By Rob Gutro
NASA’s Goddard Space Flight Center