Sep. 28, 2018 – NASA Finds Trami an Organized, Wide-Eyed Typhoon
Visible imagery from NASA’s Aqua satellite revealed Typhoon Trami was symmetrical and had a large eye on its approach to Japan’s southern islands.
At 1:05 a.m. EDT (0505 UTC) on Sept. 28 the Moderate Resolution Imaging Spectroradiometer or MODIS instrument aboard NASA’s Aqua satellite provided a visible image of Typhoon Trami in the Northwestern Pacific Ocean. The image showed the northwestern edge of Trami beginning to affect the Ryukyu Arc, a chain of Japanese islands that stretch southwest from Kyushu to Taiwan. Infrared satellite imagery shows Trami continues to have a wide eye with convection around the eye beginning to re-intensify.
On Sept. 28, the Joint Typhoon Warning Center or JTWC noted that Trami had maximum sustained winds near 90 knots (103.6 mph/166.7 kph). It was centered near 24.2 degrees north latitude and 127.0 degrees east longitude. That’s 168 nautical miles south-southwest of Kadena Air Base, Okinawa, Japan. Trami was moving north-northwest and is forecast to turn to the north-northeast.
JTWC has forecast the eye of Trami to pass just to the west of Okinawa Island, Japan and Omami Oshima Island as it moves in a north-northeasterly direction.
Sep. 28, 2018 – NASA Looks at Tropical Storm Kirk’s Caribbean Rainfall
Tropical Storm Kirk just passed through the Leeward Islands and when the GPM satellite passed overhead, it revealed that Kirk continued to bring rain to the chain on Sept. 28.
The Global Precipitation Measurement mission or GPM core satellite passed over Tropical Storm Kirk at 8:36 a.m. EDT (1236 UTC) on Friday, Sept. 28, 2018. GPM found the heaviest rainfall was around the center of circulation located west of the Leeward Islands. There, rain was falling at a rate of 100 mm (about 4 inches) per hour.
Rain extended east of the center over the island chain where rain was falling between 10 and 40 mm (0.4 and 1.5 inches) per hour. GPM is a joint mission between NASA and the Japan Aerospace Exploration Agency, JAXA.
Those rains are expected to continue affecting the islands over the next day. The National Hurricane Center said “Kirk is expected to produce total rainfall of 4 to 6 inches across the northern Windward and southern Leeward Islands with isolated maximum totals up to 10 inches across Martinique and Dominica. These rains may produce life-threatening flash floods and mudslides. Across Saint Croix and eastern Puerto Rico, Kirk is expected to bring 2 to 4 inches with isolated maximum totals of 6 inches today and Saturday, Sept. 29.”
Meanwhile, the Meteorological Service of St. Lucia has discontinued the Tropical Storm Warning for St. Lucia, and the Meteorological Service of Barbados has discontinued the Tropical Storm Watch for St. Vincent and the Grenadines.
At 11 a.m. EDT (1500 UTC), the center of Tropical Storm Kirk was located near latitude 13.8 degrees north and longitude 63.6 degrees west. That’s about 185 miles (295 km) west-southwest of Martinique.
Kirk is moving toward the west-northwest near 13 mph (20 kph), and this motion is expected to continue through Sunday. On the forecast track, the center of Kirk or its remnants will move across the eastern and central Caribbean Sea over the next day or two. Reports from an Air Force Reserve Hurricane Hunter aircraft indicate that maximum sustained winds have decreased to near 45 mph (75 kph) with higher gusts. Kirk is forecast to weaken to a tropical depression tonight, and then degenerate into a trough of low pressure on Saturday, Sept. 29.
Visible imagery from NASA’s Aqua satellite revealed that strong wind shear was adversely affecting Tropical Cyclone Liua in the Southern Pacific Ocean.
On Sept. 28 at 0315 UTC (Sept. 27 at 11:15 p.m. EDT) the Moderate Resolution Imaging Spectroradiometer or MODIS instrument aboard NASA’s Aqua satellite provided a visible image of Tropical Cyclone Liua. Liua appeared as a swirl of clouds around its center with most of its clouds and thunderstorms pushed southeast of center. Strong westerly to northwesterly vertical wind shear were tearing the storm apart.
In general, wind shear is a measure of how the speed and direction of winds change with altitude. Tropical cyclones are like rotating cylinders of winds. Each level needs to be stacked on top each other vertically in order for the storm to maintain strength or intensify. Wind shear occurs when winds at different levels of the atmosphere push against the rotating cylinder of winds, weakening the rotation by pushing it apart at different levels.
On Sept. 28, the Joint Typhoon Warning Center issued the final bulletin on Tropical Cyclone Liua. At that time, Liua was centered near 12.0 degrees south latitude and 161.1 degrees east longitude. That’s 540 miles northwest of Port Vila, Vanuatu. Liua was moving slowly to the west-northwest and had maximum sustained winds near 35 knots (40 mph/62 kph).
Liua is forecast to dissipate under adverse atmospheric conditions.
Sep. 28, 2018 – NASA Looks at Major Hurricane Rosa’s Water Vapor Concentration
When NASA’s Aqua satellite passed over the Eastern Pacific Ocean, water vapor data provided information about the intensity of Hurricane Rosa. On Sept. 28, Rosa is a major hurricane, now a Category 4 on the Saffir-Simpson Hurricane Wind Scale.
NASA’s Aqua satellite passed Hurricane Rosa on Sept. 28 at 4:55 a.m. EDT (855 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 in a thick ring of storms around the 20 nautical mile-wide eye.
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.
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 the stronger they are.
Twelve hours before the MODIS water vapor imagery, the Atmospheric Infrared Sounder instrument aboard NASA’s Aqua satellite provided temperature data on the cloud tops on Sept. 27 at 4:41 p.m. EDT (2041 UTC). Coldest cloud top temperatures were as cold as or colder than minus 70 degrees Fahrenheit (minus 56.6 degrees Celsius) around the eye and confirmed the later MODIS data.
At 5 a.m. EDT (0900 UTC), the eye of Hurricane Rosa was located near latitude 16.9 degrees north and longitude 117.3 degrees west. That’s 640 miles (1,030 km) southwest of the southern tip of Baja California, Mexico. Rosa is moving toward the west near 7 mph (11 kph). A gradual turn toward the west-northwest and northwest is expected on Friday, followed by a turn toward the north Saturday night and a turn toward the north-northeast on Sunday.
Maximum sustained winds are near 145 mph (230 kph) with higher gusts. Rosa is a category 4 hurricane on the Saffir-Simpson Hurricane Wind Scale. Little significant change in strength is forecast today, with gradual weakening anticipated by Saturday, and further weakening at a faster rate expected early next week.
NHC said although Rosa is not near the coast, swells generated by Rosa will affect portions of the coasts of southwestern Mexico, the southern Baja California Peninsula, and southern California late this week and over the weekend. These swells are likely to cause life-threatening surf and rip current conditions.
Sep. 27, 2018 – NASA Satellite Analyzes New Southern Pacific Ocean Tropical Cyclone
NASA’s Aqua satellite provided an infrared look at a new storm that formed in the southern Pacific Ocean called Liua and saw strongest storms off-center.
At 11 a.m. EDT (1500 UTC) on Sept. 27, the MODIS or Moderate Resolution Imaging Spectroradiometer instrument aboard NASA’s Aqua satellite looked at Tropical Storm Liua in infrared light. MODIS found two areas of coldest cloud top temperatures west and northeast of Liua’s center were as cold as or colder than minus 80 degrees Fahrenheit (minus 112 degrees Celsius). Those areas represented the strongest storms. Surrounding them were storms with cloud tops as cold as or colder than minus 70 degrees Fahrenheit (minus 56.6 degrees Celsius).
NASA research has found that cloud top temperatures as cold as or colder than the 70F/56.6C threshold have the capability to generate heavy rainfall.
At 11 a.m. EDT (1500 UTC), the center of Tropical Storm Liua was located near latitude 12.2 degrees south and longitude 162.5 degrees east. That’s about 471 miles northwest of Port Vila, Vanuatu. Liua was moving toward the south-southwest. Liua’s maximum sustained winds were near 40 mph (35 knots/62 kph) with higher gusts.
The Joint Typhoon Warning Center noted that the forecast takes Liua west over cooler sea surface temperatures and where outside winds will weaken the storm. Liua is forecast to dissipate by Sept. 29.
NASA-NOAA’s Suomi NPP satellite passed over the eye of Typhoon Trami as it continued moving through the Northwestern Pacific Ocean.
On Sept. 27, 2018, the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard NASA-NOAA’s Suomi NPP satellite a visible image of Trami. VIIRS infrared imagery showed a wide and ragged eye and deep convection and developing thunderstorms around. That thunderstorm development increased during the morning hours.
At 11 a.m. EDT (1500 UTC) on Sept. 27, the eye of Typhoon Trami was located near latitude 22.2 degrees north and longitude 128.6 degrees east. That’s about 275 miles south-southeast of Kadena Air Base, Okinawa Island, Japan. Maximum sustained winds were near 90 knots (103.6 mph/166.7 kph).
The Joint Typhoon Warning Center or JTWC noted that “Trami remains in a weak steering environment while in between a subtropical ridge (elongated area of high pressure) located to the west and a second subtropical ridge located to the east.” Trami is expected to eventually move to the northeast but it is forecast to re-intensify before weakening.
Sep. 27, 2018 – NASA’s Close Up of Hurricane Rosa Shows Hint of an Eye
NASA’s Terra satellite passed over the Eastern Pacific Ocean and provided forecasters with a visible image of Hurricane Rosa that gave an indication an eye has formed. Rosa is expected to become a major hurricane by Thursday, Sept. 27.
On Sept. 26 at 4:30 p.m. EDT (1630 UTC), the Moderate Resolution Imaging Spectroradiometer or MODIS instrument aboard NASA’s Terra satellite captured a visible image of Rosa. The image showed what appears to be a cloud filled-eye surrounded by bands of thunderstorms. Two thick bands of thunderstorms were wrapping into the center from the west and south.
The National Hurricane Center or NHC noted “Conventional satellite imagery show a large area of cold cloud tops near the center, and there is a hint of an eye in the first-light visible images. Microwave imagery indicates that the eye structure underneath the overcast has become better defined, with less evidence of dry air entrainment than seen yesterday.”
At 11 a.m. EDT (1500 UTC), NHC reported the center of Hurricane Rosa was located near latitude 17.2 degrees north and longitude 115.4 degrees west. Rosa is far enough away from land so no coastal warnings or watches are in effect. Rosa is about 530 miles (855 km) southwest of the southern tip of Baja California, Mexico.
Rosa is moving toward the west near 12 mph (19 kph). This general motion is expected to continue through tonight, with a slower motion toward the west-northwest on Friday and toward the northwest Friday night and Saturday. Maximum sustained winds have increased to near 105 mph (165 kph) with higher gusts. Additional strengthening is forecast through Friday, and Rosa is expected to become a major hurricane later today, Sept. 27 or tonight. The hurricane is expected to begin weakening on Saturday.
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).
NHC expects Rosa to take a turn back to the east and weaken. It is expected to make landfall in the northwestern Baja California Peninsula sometime on Oct. 2.
As Tropical Storm Kirk came back to life, the Global Precipitation Measurement mission or GPM core satellite analyzed its rainfall. Kirk is headed toward the Lesser Antilles and Warnings are in effect.
On Sept. 27, the National Hurricane Center or NHC posted a Tropical Storm Warning for Barbados, St. Lucia, Dominica, Martinique, and Guadeloupe. A Tropical Storm Watch is in effect for St. Vincent and the Grenadines.
On Sept. 25 tropical storm Kirk seemed to be dissipating but on Sept. 26 the tropical storm has sprung back to life. Convective activity near the center of tropical storm Kirk’s remnants increased and became better organized.
The GPM core observatory satellite scanned reviving tropical storm Kirk on September 25, 2018 at 7:35 p.m. (2335 UTC). Data collected by the satellite’s Microwave Imager (GMI) instrument showed that intense convective precipitation was taking place near the center of the reviving tropical storm. GMI’s scans indicated that rain was falling at over 71 mm (2.8 inches) in some of these storms. GPM’s Dual-Frequency Precipitation Radar (DPR) probed storms that were located to the east and northeast of the center of the regenerating tropical storm. DPR found rain there falling at a rate of over 69 mm (2.7 inches) per hour.
The GPM satellite’s radar data revealed the 3D structure and intensity of precipitation in the eastern side of the reviving tropical storm. The simulated 3D cross-section used GPM’s DPR Ku Band data were created at NASA’s Goddard Space Flight Center in Greenbelt, Maryland showed the heavy precipitation falling east of the tropical storm. The satellite found that this area of precipitation was returning strong radar echoes of almost 60 dBZ to the satellite.
The term dBz is basically a measure of the strength of the reflected energy. The higher the dBz value, the stronger the intensity of the precipitation detected by the radar.
The GPM core observatory satellite scanned reviving tropical storm Kirk on September 25, 2018 at 7:35 p.m. (2335 UTC). Rain was falling at over 71 mm (2.8 inches) in storms around the center. Storms located to the east and northeast of the center of the regenerating tropical storm had rainfall at a rate of over 69 mm (2.7 inches) per hour. Credit: NASA/JAXA, Hal Pierce
GPM also found that precipitation was reaching heights above 11.2 km (6.9 miles) in a few powerful storms. GPM is a joint mission between NASA and the Japan Aerospace Exploration Agency, JAXA.
At 11 a.m. EDT (1500 UTC) on Sept. 27 the center of Tropical Storm Kirk was located near latitude 13.8 degrees north and longitude 59.3 degrees west. That’s about 45 miles (70 km) north-northeast of Barbados. Kirk was moving toward the west-northwest near 15 mph (24 kph) and this general motion with a slight decrease in forward speed is expected over the next few days. On the forecast track, the center of Kirk will move across the Lesser Antilles within the Tropical Storm Warning area by this evening.
Maximum sustained winds are near 50 mph (85 kph) with higher gusts. Gradual weakening is anticipated during the next couple of days, but Kirk is forecast to move across the Lesser Antilles and into the eastern Caribbean Sea as a tropical storm.
The National Hurricane Center (NHC) noted that the heavy rainfall detected by GPM will be affecting the warning area. NHC said “Kirk is expected to produce total rainfall of 4 to 6 inches across the northern Windward and southern Leeward Islands with isolated maximum totals up to 10 inches across Martinique and Dominica. These rains may produce life-threatening flash floods and mudslides. Across eastern Puerto Rico, Kirk is expected to bring 2 to 4 inches with isolated maximum totals of 6 inches by Friday and Saturday, Sept. 29.”
Interests elsewhere in the central and northern Lesser Antilles should monitor the progress of Kirk.
Sep. 26, 2018 – NASA-NOAA’s Suomi NPP Satellite Gets an Infrared View Typhoon Trami
Typhoon Trami looked formidable in infrared imagery taken from NASA-NOAA’s Suomi NPP satellite as it moves to the southern Islands of Japan.
NASA-NOAA’s Suomi NPP satellite provided forecasters with a night-time and infrared look at Trami’s clouds on Sept. 25 at 1724 UTC (1:24 p.m. EDT). Cloud top temperatures were near 190 Kelvin/ minus 117.7 degrees Fahrenheit / minus 83.5 degrees Celsius around the eye of the storm. Cloud tops that cold can produce heavy rainfall.
William Straka III of the University of Wisconsin-Madison, Space Science and Engineering Center (SSEC) Cooperative Institute for Meteorological Satellite Studies (CIMSS), Madison, created the images. Straka said, “The infrared imagery showed a wide eye along with the obvious convection and tropospheric gravity waves.”
At 11 a.m. EDT (1500 UTC) Trami’s center was located near latitude 21.3 North, longitude 129.3 West. That’s about 321 nautical miles south-southeast of Kadena Air Base, Okinawa, Japan. Maximum sustained winds are near 103 mph (90 knots/166 kph) with higher gusts.
The Joint Typhoon Warning Center forecast calls for Trami to weaken slowly as the storm moves slowly north. The storm will then re-strengthen to 110 knots, after which it will become extra-tropical. The typhoon will become extra-tropical on passing Honshu.
Sep. 26, 2018 – Tropical Depression 29W Spins Up in Northwestern Pacific Ocean
The first warning issued by the Joint Typhoon Warning Center for Tropical Depression 29W was early on September 26 (0600 GMT). The second warning for this active tropical storm came out at (1500 GMT).
This storm is located near 30.1N 151.2E, that is, 615 miles east northeast of Iwo To off the eastern coast of Japan. Its movement has been northward at 14 knots (16 mph). Wave height is approximately 10 feet and no land masses are threatened at present.
In the next 12 hours the storm is forecast to have maximum sustained winds of 30 knots with gusts up to 40 knots (34 to 46 mph) per hour over open water.
Tropical Storm 27W is forecast to strengthen but become extratropical in the next 24 hours.