Oct. 13, 2020 – NASA Animation Tracks the End of Tropical Storm Delta
NASA’s Terra satellite obtained visible imagery as Tropical Storm Delta made landfall in Louisiana and moved northeastward soaking the U.S. southeast and Mid-Atlantic states.
NASA’s Terra satellite provided a visible image to forecasters of Tropical Storm Delta moving through the southeastern U.S. on Oct. 11 at 1:30 p.m. EDT. At the time of the image, the storm was centered over northern Alabama. Image Courtesy: NASA Worldview, Earth Observing System Data and Information System (EOSDIS).
NASA Satellite View: Delta’s Organization
The Moderate Resolution Imaging Spectroradiometer or MODIS instrument that flies aboard NASA’s Terra satellite captured a visible image of Tropical Storm Delta on Oct. 11 at 1:30 p.m. EDT. The storm still appeared circular in imagery. At the time, it was centered over northern Alabama. At the time Terra passed overhead, Delta had weakened to a tropical depression with maximum sustained winds near 25 mph (35 kph).
Visible imagery from NASA’s Terra satellite captured from Oct. 9 to Oct. 12 were compiled into an animation. The animation showed the landfall and movement of Tropical Storm Delta. Delta dissipated over the southeastern U.S. and its remnants moved into the Atlantic states. The animation was created using NASA’s Worldview product at NASA’s Goddard Space Flight Center in Greenbelt, Md.
This animation of visible imagery from NASA Terra satellite shows the landfall and movement of Tropical Storm Delta from Oct. 9 to Oct. 12. Delta dissipated over the southeastern U.S. and its remnants moved into the Atlantic states. Image Courtesy: NASA Worldview, Earth Observing System Data and Information System (EOSDIS).
Delta’s Landfall on Oct. 9
National Weather Service Doppler radar imagery, Air Force Reserve Hurricane Hunter aircraft data, and surface observations indicated on Oct. 9 that Delta made landfall near Creole, Louisiana, around 7 p.m. EDT with estimated maximum sustained winds of 100 mph (155 kph). Delta was a category 2 hurricane on the Saffir-Simpson Hurricane Wind Scale.
Delta’s Final Advisory
The National Hurricane Center (NHC) issued the final advisory on Delta at 11 p.m. EDT on Oct. 11 (Oct. 12 at 0300 UTC). At that time, the center of Post-Tropical Cyclone Delta was located near latitude 34.5 degrees north and longitude 84.1 degrees west. It was just 60 miles (95 km) north-northeast of Atlanta, Georgia. The post-tropical cyclone was moving toward the east near 15 mph. Maximum sustained winds were near 15 mph (30 kph) with higher gusts.
NHC said, “Some further weakening is possible tonight as a new surface low develops in the Carolinas, and Delta’s surface low is expected to be absorbed by this new low pressure area on Monday, Oct. 12.”
About NASA’s Worldview and Terra 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 Terra 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.
Oct. 09, 2020 – GPM Captures Hurricane Delta on Approach to the Gulf Coast
The NASA / JAXA GPM Core Observatory satellite passed over Hurricane Delta Thursday October 8, 2020 at approximately 7:40pm CT (00:40 UTC on 10/9/2020), capturing data on the intensity of precipitation within the storm as it approached the Gulf Coast.
Credit: NASA
Hurricane Delta is the 25th named Atlantic storm of the 2020 hurricane season. After exhausting a list of prepared names, the World Meteorological Organization turns to the Greek alphabet to name storms. Delta marks the strongest Greek-named storm on record.
Hurricanes typically get a massive boost of energy when they pass over warm waters. Hurricane Delta rapidly intensified from a tropical depression to Category 4 storm in about 30 hours.
Oct. 09, 2020 – NASA Finds Hurricane Delta Packing Heavy Rainfall
NASA’s satellite rainfall product that incorporates data from satellites and observations found that Hurricane Delta was bringing along heavy rainfall as it headed to the U.S. Gulf Coast on Oct. 9.
On Oct. 9 at 5:30 a.m. EDT (0930 UTC), NASA’s IMERG estimated Delta was generating as much as 50 mm(~2 inches of rain [dark red]) around the center of circulation. Rainfall rates in storms surrounding those areas of heaviest rainfall (green, pink, red) were estimated as falling at a rate between 10 and 40 mm (0.4 to 1.6 inches) per hour. The rainfall data was overlaid on infrared imagery from NOAA’s GOES-16 satellite. Credit: NASA/NOAA/NRLWarnings and Watches in Effect on Oct. 9
There are many warnings in effect, as Delta approaches the U.S. Gulf coast. A Storm Surge Warning is in effect from High Island, Texas to Mouth of the Pearl River, Louisiana including Calcasieu Lake, Vermilion Bay, and Lake Borgne.
A Hurricane Warning is in effect from High Island, Texas to Morgan City, Louisiana. A Tropical Storm Warning is in effect from west of High Island to Sargent, Texas and east of Morgan City, Louisiana to the mouth of the Pearl River, including New Orleans and Lake Pontchartrain and Lake Maurepas.
Delta’s Status on Oct. 9
At 11 a.m. (1500 UTC), the center of Hurricane Delta was located near latitude 28.0 degrees north and longitude 93.8 degrees west. That is about 130 miles (205 km) south-southwest of Cameron, Louisiana.
Delta is moving toward the north near 13 mph (20 kph). A turn toward the north- northeast is expected this afternoon, followed by a northeastward motion during the day Saturday. Maximum sustained winds are near 115 mph (185 kph) with higher gusts. Delta is a category 3 hurricane on the Saffir-Simpson Hurricane Wind Scale. The latest minimum central pressure estimated from NOAA Hurricane Hunter aircraft data is 962 millibars.
Estimating Delta’s Rainfall Rates from Space
NASA’s Integrated Multi-satellitE Retrievals for GPM or IMERG, which is a NASA satellite rainfall product, estimated Delta’s rainfall rates.
On Oct. 9 at 5:30 a.m. EDT (0930 UTC), NASA’s IMERG estimated Delta was generating as much as 50 mm (~2 inches of rain) around the center of circulation. Rainfall rates in storms surrounding those areas of heaviest rainfall were estimated as falling at a rate between 10 and 40 mm (0.4 to 1.6 inches) per hour.
At the U.S. Naval Laboratory in Washington, D.C., the IMERG rainfall data was overlaid on infrared imagery from NOAA’s GOES-16 satellite to provide a full extent of the storm.
What Does IMERG Do?
This near-real time rainfall estimate comes from the NASA’s IMERG, which combines observations from a fleet of satellites, in near-real time, to provide near-global estimates of precipitation every 30 minutes. By combining NASA precipitation estimates with other data sources, we can gain a greater understanding of major storms that affect our planet.
What the IMERG does is “morph” high-quality satellite observations along the direction of the steering winds to deliver information about rain at times and places where such satellite overflights did not occur. Information morphing is particularly important over the majority of the world’s surface that lacks ground-radar coverage. IMERG fills in the blanks between weather observation stations.
Delta’s Heavy Rainfall Forecast
NASA’s rainfall data is provided to forecasters at the National Hurricane Center and is reflected in one of the key messages.
NHC said, “Today through Saturday, Delta is expected to produce 5 to 10 inches of rain, with isolated maximum totals of 15 inches, from southwest into central Louisiana. These rainfall amounts will lead to significant flash, urban, small stream flooding, along with minor to major river flooding.
For extreme east Texas into northern Louisiana, southern Arkansas, and western Mississippi, Delta is expected to produce 3 to 6 inches of rain, with isolated maximum totals of 10 inches. These rainfall amounts will lead to flash, urban, small stream, and isolated minor river flooding.
As the remnants of Delta move further inland 1 to 3 inches of rain, with locally higher amounts, are expected in the Tennessee Valley and Mid- Atlantic this weekend. There is a potential for 3 to 6 inches in the Southern Appalachians, which could lead to isolated flash, urban, and small stream flooding.”
Additional NHC Key Messages
In addition the heavy and flooding rainfall expected, NHC’s other key messages are about storm surge, hurricane-force winds, isolated tornadoes and dangerous surf:
STORM SURGE: The combination of a dangerous storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline. The water could reach the following heights above ground somewhere in the indicated areas if the peak surge occurs at the time of high tide:
Rockefeller Wildlife Refuge to Morgan City, LA including Vermilion Bay…7-11 ft
Holly Beach, LA to Rockefeller Wildlife Refuge, LA…5-8 ft
Sabine Pass to Holly Beach, LA…3-5 ft
Morgan City, LA to Port Fourchon, LA…4-7 ft
Port Fourchon, LA to the Mouth of the Mississippi River…2-4 ft
Calcasieu Lake…2-4 ft
High Island, TX to Sabine Pass…2-4 ft
Mouth of the Mississippi River to Mouth of the Pearl River…2-4 ft
Lake Borgne…2-4 ft
Lake Pontchartrain and Lake Maurepas…1-3 ft
Mouth of the Pearl River, LA to the AL/FL border including Mobile Bay…1-3 ft
Sabine Lake…1-3 ft
Port O’Connor, TX to High Island, TX including Galveston Bay…1-3 ft
It is important to note that small changes in the track, structure, or intensity of Delta could have large impacts on where the highest storm surge occurs.
WIND: Hurricane conditions are expected within the hurricane warning area by this afternoon, with tropical storm conditions expected within this area later this morning. Tropical storm conditions are expected within the tropical storm warning areas later today.
TORNADOES: A few tornadoes are possible today and tonight over southern portions of Louisiana and Mississippi.
SURF: Swells from Delta are affecting portions of the northern and western Gulf coast. These swells are likely to cause life-threatening surf and rip current conditions.
Delta’s Expected Track
NHC forecasters said slow weakening is expected before landfall, with rapid weakening expected after the center moves inland. On the forecast track, the center of Delta should make landfall along the coast of southwestern Louisiana later this afternoon or this evening, and then move across central and northeastern Louisiana tonight and Saturday morning.
NASA Researches Tropical Cyclones
Hurricanes/tropical cyclones 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 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.
Oct. 08, 2020 – NASA Examines Hurricane Delta’s Early Morning Structure
The NASA-NOAA Suomi NPP satellite provided two nighttime views of Hurricane Delta as it moved toward the U.S. Gulf Coast. A moonlit image and an infrared image revealed the extent and organization of the intensifying hurricane.
The Waning Gibbous moon (65% illumination) was enough to see both the tropospheric waves as well as the central dense overcast and long ranging feeder bands in Hurricane Delta on Oct. 8 at 4:05 a.m. EDT. Credit: UWM/SSEC/CIMSS/William Straka III
Satellite Imagery Shows Delta’s Extent
On Oct. 8 at 4:05 a.m. EDT (0805 UTC), the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard NASA-NOAA’s Suomi NPP satellite captured an infrared and nighttime imagery of Hurricane Delta as it moved through the Gulf of Mexico.
One hour before Suomi NPP passed overhead, Delta had winds of 100 mph, making it a Category 2 storm on the Saffir-Simpson Hurricane Wind Scale. “The imagery showed enhanced convection near the center of circulation, though the actual circulation was covered by a central dense overcast (CDO) feature, but the curved bands beyond that, extending all the way to the U.S., can also be seen,” noted William Straka III, researcher at University of Wisconsin – Madison’s Space Science and Engineering Center, Cooperative Institute for Meteorological Satellite Studies, Wisconsin.
On Oct. 8 at 4:05 a.m. EDT (0805 UTC), the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard NASA-NOAA’s Suomi NPP satellite captured an infrared image of Hurricane Delta. It revealed enhanced convection near the center of circulation, and bands of thunderstorms extended all the way to the U.S. Credit: UWM/SSEC/CIMSS/William Straka III
“The Waning Gibbous moon (65% illumination) was enough to see both the tropospheric waves as well as the CDO and long ranging feeder bands (of thunderstorms.”
On Oct. 8 at 3:35 a.m. EDT (0735 UTC) NASA’s Aqua satellite analyzed Delta using the Atmospheric Infrared Sounder or AIRS instrument. AIRS found coldest cloud top temperatures as cold as or colder 210 Kelvin minus 81 degrees Fahrenheit (minus 63.1 degrees Celsius). NASA research has shown that cloud top temperatures that cold indicate strong storms that have the capability to create heavy rain. The eye was obscured by high clouds and central dense overcast.
On Oct. 8 at 3:35 a.m. EDT (0735 UTC) NASA’s Aqua satellite analyzed Hurricane Delta using the Atmospheric Infrared Sounder or AIRS instrument. AIRS found coldest cloud top temperatures as cold as or colder 210 Kelvin minus 81 degrees Fahrenheit (minus 63.1 degrees Celsius). The eye was obscured by high clouds. Credit: NASA/JPL/Heidar Thrastarson
NASA provides all of this data to tropical cyclone meteorologists so they can incorporate it in their forecasts.
NHC forecaster Jack Beven noted, “Satellite imagery shows that Delta is better organized this morning, with the center well embedded in a cold central dense overcast and a hint of an eye developing in the overcast.”
Watches and Warnings on Oct. 8
NOAA’s National Hurricane Center (NHC) has issued various warnings and watches for Delta’s approach to the U.S. mainland.
A Storm Surge Warning is in effect for High Island, Texas to Ocean Springs, Mississippi including Calcasieu Lake, Vermilion Bay, Lake Pontchartrain, Lake Maurepas, and Lake Borgne.
A Hurricane Warning is in effect from High Island, Texas to Morgan City, Louisiana. A Tropical Storm Warning is in effect from west of High Island to San Luis Pass, Texas and from east of Morgan City Louisiana to the mouth of the Pearl River, including New Orleans. A Hurricane Warning is also in effect for Lake Pontchartrain and Lake Maurepas.
A Tropical Storm Watch is in effect from east of the mouth of the Pearl River to Bay St. Louis Mississippi.
Delta’s Status on Oct. 8
At 11 a.m. EDT (1500 UTC), the center of Hurricane Delta was located near latitude 24.0 degrees north and longitude 92.7 degrees west. That is about 400 miles (645 km) south of Cameron, Louisiana. Delta was moving toward the northwest near 14 mph (22 kph), and this motion with a reduction in forward speed is expected today. Reports from NOAA and Air Force Reserve Hurricane Hunter aircraft indicate that maximum sustained winds have increased to near 105 mph (165 kph) with higher gusts. The latest minimum central pressure reported by the Hurricane Hunter aircraft is 968 millibars.
Delta’s Forecast
NHC expects a turn toward the north by late tonight, followed by a north-northeastward motion by Friday afternoon or Friday night. Additional strengthening is forecast, and Delta is expected to become a major hurricane again by tonight. On the forecast track, the center of Delta will move over the central Gulf of Mexico today, over the northwestern Gulf of Mexico on Friday. Some weakening is possible as Delta approaches the northern Gulf coast on Friday, with rapid weakening expected after the center moves inland within the hurricane warning area Friday afternoon or Friday night.
NASA Researches Earth from Space
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.
Oct. 07, 2020 – NASA Analyzes Hurricane Delta’s Water Vapor Concentration
When NASA’s Aqua satellite passed over the Caribbean Sea on Oct. 7, it gathered water vapor data on Hurricane Delta as Mexico’s Yucatan continues to feel its effects.
On Oct. 7 at 2:50 a.m. EDT (0650 UTC), NASA’s Aqua satellite found highest concentrations of water vapor (brown) and coldest cloud top temperatures were around Hurricane Delta’s center. Cloud top temperatures in those storms were as cold as or colder than minus 90 degrees Fahrenheit (minus 67.7 degrees Celsius). Delta was moving over Mexico’s Yucatan Peninsula. 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 Delta on Oct. 7 at 2:50 a.m. EDT (0650 UTC), and the Moderate Resolution Imaging Spectroradiometer or MODIS instrument gathered water vapor content and temperature information. NASA’s Aqua satellite is one in a fleet of NASA satellites that provide data for hurricane research.
The MODIS image showed highest concentrations of water vapor and coldest cloud top temperatures were around the center of circulation and east of the center. Strongest storms were over the northern Caribbean Sea, between Mexico’s Yucatan Peninsula and western Cuba. MODIS data also showed coldest cloud top temperatures were as cold as or colder than minus 90 degrees Fahrenheit (minus 67.7 degrees Celsius) in those storms. Storms with cloud top temperatures that cold have the capability to produce heavy rainfall.
At 5 a.m. EDT, NHC Senior Hurricane Specialist Eric Blake said, “Satellite images show very deep convection associated with Delta, with extremely cold cloud-top temperatures to minus 97 degrees Celsius noted southwest of the center overnight. However, this structure has not resulted in a stronger cyclone, and the full NOAA Hurricane Hunter aircraft mission actually indicated that Delta has significantly weakened since earlier today.”
Forecasters at the National Hurricane Center (NHC) noted, “Through early Thursday, Delta is expected to produce 4 to 6 inches of rain, with isolated maximum totals of 10 inches, across portions of the northern Yucatan Peninsula. This rainfall may result in areas of significant flash flooding. In addition, 2 to 4 inches of rain, with isolated higher amounts, are expected across portions of western Cuba. This rainfall may result in areas of flash flooding and mudslides.”
Warnings and Watches on Oct. 7
NHC issued a Hurricane Warning from Tulum to Dzilam, Mexico and for Cozumel. A Tropical Storm Warning is in effect for the Cuban province of Pinar del Rio; from Punta Herrero to Tulum, Mexico; and from Dzilam to Progreso, Mexico.
Delta’s Status on Oct. 7
At 8 a.m. EDT (1200 UTC), the NHC said the center of Hurricane Delta was located by satellite images and surface observation inland over northeastern Mexico near latitude 21.1 degrees north and longitude 87.4 degrees west. Delta was centered just 35 miles (55 km) west of Cancun, Mexico.
Delta was moving toward the northwest near 17 mph (28 kph). A west northwestward-to-northwestward motion is expected over the next day or so. A slower northwestward to north-northwestward motion is forecast to begin on Thursday, and a northward motion is likely Thursday night and Friday. Maximum sustained winds are near 105 mph (165 kph) with higher gusts. The estimated minimum central pressure based on surface observations is 974 millibars.
Delta’s Forecast Track
NHC forecasters said, “Although some additional weakening is likely when Delta moves over the Yucatan peninsula this morning, re-strengthening is forecast when the hurricane moves over the southern Gulf of Mexico Wednesday night and Thursday, and Delta could become a category 4 hurricane again by late Thursday. Weakening is expected as Delta approaches the northern Gulf coast on Friday.
On the forecast track, Delta is expected to move over the southern Gulf of Mexico during the afternoon of Oct. 7 and be over the southern or central Gulf of Mexico through Thursday. Delta is expected to approach the northern Gulf coast on Friday, Oct. 9.”
NASA Researches Tropical Cyclones
Hurricanes/tropical cyclones 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 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.
Infrared imagery from NASA-NOAA’s Suomi NPP satellite revealed that Hurricane Delta has been rapidly growing stronger and more powerful. Infrared imagery revealed that powerful thunderstorms circled the eye of the hurricane and southern quadrant as it moved through the Caribbean Sea on Oct. 6.
On Oct. 6 at 3:06 a.m. EDT (0706 UTC) NASA-NOAA’s Suomi NPP satellite analyzed Hurricane Delta’s cloud top temperatures and found strongest storms (yellow) were around Delta’s center of circulation and in a band of thunderstorms south of the center. Temperatures in those areas were as cold as minus 80 degrees Fahrenheit (minus 62.2 Celsius). Strong storms with cloud top temperatures as cold as minus 70 degrees (red) Fahrenheit (minus 56.6. degrees Celsius) surrounded both of those areas. Credit: NASA/NRL
At 11:20 a.m. EDT on Oct. 6, NOAA’s National Hurricane Center (NHC) received data from a NOAA hurricane hunter aircraft that Delta has rapidly strengthened into a category 4 hurricane.
Infrared Imagery Reveals a More Powerful Delta
One of the ways NASA researches tropical cyclones is by using infrared data which provides temperature information. Cloud top temperatures identify where the strongest storms are located. The stronger the storms, the higher they extend into the troposphere, and the colder the cloud top temperatures.
On Oct. 6 at 3:06 a.m. EDT (0706 UTC) NASA-NOAA’s Suomi NPP satellite analyzed Hurricane Delta’s cloud top temperatures using the Visible Infrared Imaging Radiometer Suite or VIIRS instrument. At the time, Delta was a Category 1 hurricane with maximum sustained winds near 85 mph (140 kph). By 5 a.m. EDT, maximum sustained winds strengthened to 100 mph (155 kph). The storm continued to intensify rapidly during the morning hours.
VIIRS found strongest storms were around Delta’s center of circulation and in a band of thunderstorms south of the center. Temperatures in those areas were as cold as minus 80 degrees Fahrenheit (minus 62.2 Celsius). Strong storms with cloud top temperatures as cold as minus 70 degrees Fahrenheit (minus 56.6. degrees Celsius) surrounded both of those areas.
NASA research has shown that cloud top temperatures that cold indicate strong storms that have the capability to create heavy rain. NASA provides data to tropical cyclone meteorologists so they can incorporate it in their forecasts.
Warnings and Watches on Oct. 6
A Hurricane Warning is in effect from Tulum to Dzilam, Mexico and for Cozumel. A Tropical Storm Warning is in effect for the Cayman Islands including Little Cayman and Cayman Brac and for the Cuban province of Pinar del Rio and the Isle of Youth. A Tropical Storm Warning is also in effect from Punta Herrero to Tulum, Mexico and from Dzilam to Progresso, Mexico. A Tropical Storm Watch is in effect for the Cuban province of La Habana.
Delta’s Status on Oct. 6
At 11:20 a.m. EDT, data from a NOAA Hurricane Hunter aircraft indicate that Delta is continuing to strengthen rapidly. The maximum winds have increased to near 130 mph (215 kph) with higher gusts. This makes Delta a category 4 hurricane on the Saffir-Simpson Hurricane Wind Scale.
Delta was centered near latitude 18.2 degrees north and longitude 82.7 degrees west, about 315 miles (510 km) east-southeast of Cozumel, Mexico. Delta is moving to the west-northwest at 16 mph (26 kph) and has a minimum central pressure near 954 millibars.
NHC Key Messages for Delta
The NHC issued several key messages about Delta today, Oct. 6:
STORM SURGE: An extremely dangerous storm surge will raise water levels by as much as 6 to 9 feet above normal tide levels along coast of the Yucatan peninsula within the hurricane warning area, near and to right of where the center makes landfall. Near the coast, the surge will be accompanied by large and destructive waves.
WIND: Tropical storm conditions are expected in portions of the Cayman Islands today. In the Yucatan Peninsula, hurricane conditions are expected in the warning area early Wednesday, with tropical storm conditions beginning later today or tonight. Tropical storm conditions are expected in the tropical storm warning area tonight and Wednesday. In Cuba, tropical storm conditions are expected tonight in the warning area and possible in the watch area near the same time.
RAINFALL: Delta is expected to produce 4 to 6 inches of rain, with isolated maximum totals of 10 inches, across portions of the northern Yucatan Peninsula through midweek. This rainfall may result in areas of significant flash flooding.
Over the next few days, Delta is expected to produce 2 to 4 inches of rain, with isolated higher amounts, across portions of the Cayman Islands and western Cuba. This rainfall may result in areas of flash flooding and mudslides.
Delta’s Forecast
NHC noted, “A slower northwestward to north-northwest motion is forecast to begin by late Wednesday or Wednesday night. On the forecast track, the center of Delta is expected to continue to pass southwest of the Cayman Islands through early this afternoon, and move over the northeastern portion of the Yucatan peninsula late tonight or early Wednesday. Delta is forecast to move over the southern Gulf of Mexico Wednesday afternoon, and be over the southern or central Gulf of Mexico through Thursday.”
What Happened to Gamma’s Remnants?
The remnant low-pressure area of Gamma was located off the north coast of Yucatan at 8 a.m. EDT. Gamma has since moved inland and is forecast to dissipate on Wednesday.
NASA Researches Earth from Space
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.
Oct. 05, 2020 – NASA Gages Tropical Storm Delta’s Strength in Infrared
NASA’s Aqua satellite analyzed Tropical Storm Delta in infrared imagery as it moved through the Caribbean Sea. The imagery provided cloud top temperatures to identify the strongest areas within the storm.
On Oct. 5 at 3:05 a.m. EDT (0705 UTC) NASA’s Aqua satellite analyzed Tropical Storm Delta using the Atmospheric Infrared Sounder or AIRS instrument. AIRS found coldest cloud top temperatures as cold as or colder than (purple) minus 63 degrees Fahrenheit (minus 53 degrees Celsius) around the center of circulation. Credit: NASA JPL/Heidar Thrastarson
Potential Tropical Cyclone 26 formed in the Caribbean Sea on Sunday, Oct. 4 by 5 p.m. EDT. Six hours later, the National Hurricane Center (NHC) classified it as Tropical Depression 26. By 8 a.m. EDT, satellite imagery helped confirm that the depression had strengthened into a tropical storm. At that time, it was given the name Delta.
Analyzing Delta’s Temperatures and Strength
One of the ways NASA researches tropical cyclones is using infrared data that provides temperature information. The AIRS instrument aboard NASA’s Aqua satellite captured a look at those temperatures in Delta and gave insight into the size of the storm and its rainfall potential.
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 the colder the cloud top temperatures. NASA provides that data to forecasters at NOAA’s National Hurricane Center or NHC so they can incorporate in their forecasting.
On Oct. 5 at 3:05 a.m. EDT (0705 UTC) NASA’s Aqua satellite analyzed Tropical Storm Delta using the Atmospheric Infrared Sounder or AIRS instrument. AIRS found coldest cloud top temperatures as cold as or colder than (purple) minus 63 degrees Fahrenheit (minus 53 degrees Celsius) around the center of circulation. NASA research has shown that cloud top temperatures that cold indicate strong storms that have the capability to create heavy rain.
When meteorologists studied satellite imagery, including infrared imagery, it was noted that deep convection (rising air that forms the thunderstorms that make up a tropical cyclone) had been steadily improving in both vertical depth and structure of the storm since 2 a.m. EDT. Even the cloud pattern was becoming more circular with upper-level outflow of air at the top of the storm now having become established in all quadrants. That is an indication of improvement in a storm’s structure.
NHC noted, “However, there are still some indications in satellite imagery that the low-level and the mid-upper-level circulations are not yet vertically aligned, with the low-level center still located just inside the northern edge of the convective cloud shield.”
Eight hours after the AIRS image, the convective structure of Delta continued to improve. Earlier microwave data and early-light visible satellite imagery showed that the center of the tropical cyclone re-formed farther south within the area of deep convection.
Warnings and Watches on Oct. 5
NOAA’s National Hurricane Center has issued a number of watches and warnings for Delta on Oct. 5. A Hurricane Warning is in effect for Cuba’s province of Pinar del Rio. A Tropical Storm Warning is in effect for the Cayman Islands including Little Cayman and Cayman Brac, and for the Isle of Youth.
A Hurricane Watch is in effect for the Cuban province of Artemisa and for the Isle of Youth. A Tropical Storm Watch is in effect for the Cuban province of La Habana.
Delta’s Status
At 11 a.m. EDT (1500 UTC) on Oct. 5, the center of Tropical Storm Delta was located near latitude 16.4 degrees north and longitude 78.6 degrees west. Delta is centered about 135 miles (215 km) south of Negril, Jamaica and about 265 miles (425 km) southeast of Grand Cayman.
Delta is moving toward the west near 7 mph (11 kph), and a turn toward the west-northwest is forecast later today. A faster northwestward motion is expected on Tuesday (Oct. 6) and Wednesday (Oct. 7). Maximum sustained winds have increased to near 45 mph (75 kph) with higher gusts. The estimated minimum central pressure is 1002 millibars.
Delta’s Forecast
NHC expects additional strengthening during the next few days, and Delta is expected to become a hurricane on Tuesday before it nears western Cuba. On the forecast track, the center of Delta is expected to move away from Jamaica later today, move near or over the Cayman Islands early Tuesday, and approach western Cuba Tuesday afternoon or evening. Delta is forecast to move into the southeastern Gulf of Mexico Tuesday night, and be over the south-central Gulf of Mexico on Wednesday.
About NASA’s AIRS Instrument
The AIRS instrument is one of six instruments flying on board NASA’s Aqua satellite, launched on May 4, 2002.
AIRS, in conjunction with the Advanced Microwave Sounding Unit (AMSU), senses emitted infrared and microwave radiation from Earth to provide a three-dimensional look at Earth’s weather and climate. Working in tandem, the two instruments make simultaneous observations down to Earth’s surface. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, three-dimensional map of atmospheric temperature and humidity, cloud amounts and heights, greenhouse gas concentrations and many other atmospheric phenomena. Launched into Earth orbit in 2002, the AIRS and AMSU instruments fly aboard NASA’s Aqua spacecraft. They are managed by NASA’s Jet Propulsion Laboratory (JPL) in Southern California, under contract to NASA. JPL is a division of Caltech.
NASA Research
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.
