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.
Sep. 26, 2018 – Suomi NPP Satellite Sees Rosa Intensifying into Tenth Eastern Pacific Hurricane
NASA-NOAA’s Suomi NPP satellite passed over the Eastern Pacific Ocean as Tropical Storm Rosa was strengthening into that ocean basin’s tenth hurricane.
On Sept. 25, the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard NASA-NOAA’s Suomi NPP satellite provided a visible light image of Tropical Storm Rosa. The VIIRS image showed powerful thunderstorms around the center of circulation and thick bands of thunderstorms spiraling into the center from the northern and eastern quadrants.
At 11 a.m. EDT (1500 UTC), the center of Hurricane Rosa was located near latitude 16.1 degrees north and longitude 111.4 degrees west. That’s 510 miles (820 km) west-southwest of Manzanillo, Mexico. Rosa is moving toward the west-northwest near 10 mph (17 kph), and this general motion is forecast to continue for the next two days. A turn to the northwest is expected by Saturday morning. Maximum sustained winds have quickly increased to near 75 mph (120 kph) with higher gusts, and rapid strengthening is forecast to continue through tonight.
Rosa is expected to become a major hurricane on Thursday, Sept. 27.
Sep. 26, 2018 – Suomi NPP Satellite Observes Rebirth of Tropical Storm Kirk, Warnings Up
NASA-NOAA’s Suomi NPP satellite passed over Tropical Storm Kirk as it was regenerating in the Atlantic Ocean. Because Kirk regenerated east of the Caribbean Sea, warnings and watches were posted for the Lesser Antilles.
On Sept. 25 at 12:30 p.m. EDT (1630 UTC) the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard NASA-NOAA’s Suomi NPP satellite provided a visible light image of re-forming Tropical Storm Kirk. The VIIRS image showed central convection and forming thunderstorms around the center of circulation.
Kirk officially regenerated on Sept. 26 at 5 a.m. EDT as a tropical storm. At that time NOAA’s National Hurricane Center or NHC noted “two earlier ASCAT scatterometer [instrument] passes between [8 p.m. and 9 p.m. EDT on Sept. 25] 0000-0100Z on Sept 26 indicated that the low-level center had become a little better defined, and that the inner-core wind field had contracted, now with a radius of maximum winds of about 40 nautical miles. Given the continued increase in the amount and organization of the deep convection, advisories have be re-initiated on Tropical Storm Kirk.”
A Tropical Storm Warning is in effect for Barbados, St. Lucia, Dominica, Martinique and Guadeloupe. A Tropical Storm Watch is in effect for St. Vincent and the Grenadines.
At 11 a.m. EDT (1500 UTC) on Sept. 26 the center of Tropical Storm Kirk was located near latitude 12.1 degrees north and longitude 54.3 degrees west. That’s about 360 miles (575 km) east-southeast of Barbados and 485 miles (780 km) east-southeast of Martinique.
Kirk is moving toward the west near 18 mph (30 kph). A westward to west-northwestward motion is expected over the next few days. On the forecast track, the center will move over the Lesser Antilles within the Tropical Storm Warning area Thursday night. Maximum sustained winds have increased to near 50 mph (85 kph) with higher gusts. Little change in strength is forecast until Kirk crosses the Lesser Antilles, followed by weakening over the eastern Caribbean Sea.
Sep. 25, 2018 – NASA Gets a Final Look at Leslie as a Subtropical Storm
NASA’s Aqua satellite passed over the Central North Atlantic Ocean and analyzed Subtropical Storm Leslie in infrared light to determine what was happening within.
At the time of Aqua’s overpass from space, Leslie was transitioning from a subtropical to a post-tropical storm.
Infrared Imagery Shows Dry Air Sapping Leslie
Infrared satellite data captured at 1:05 a.m. EDT (0505 UTC) on Sept. 25, the Moderate Resolution Imaging Spectroradiometer or MODIS instrument aboard NASA’s Aqua satellite revealed strongest storms with the coldest cloud top temperatures east and southeast of Leslie’s center. MODIS found coldest cloud tops had temperatures near minus 63 degrees Fahrenheit (minus 53 degrees Celsius). NASA research has found that cloud top temperatures that cold have the capability to generate heavy rainfall.
The western quadrant appeared devoid of clouds because dry air had moved into the western side of the storm, suppressing thunderstorm development.
What is a Sub-tropical Storm?
A sub-tropical storm is a low-pressure system that is not associated with a frontal system and has characteristics of both tropical and extratropical cyclones. Like tropical cyclones, they are non-frontal that originate over tropical or subtropical waters, and have a closed surface wind circulation about a well-defined center. Unlike tropical cyclones, subtropical cyclones derive a significant proportion of their energy from baroclinic sources (atmospheric pressure), and are generally cold-core in the upper troposphere, often being associated with an upper-level low pressure area or an elongated area or trough of low pressure. In comparison to tropical cyclones, these systems generally have a radius of maximum winds occurring relatively far from the center (usually greater than 60 nautical miles), and are generally less symmetric.
What is a Post-tropical Storm?
The National Hurricane Center or NHC defines a post-tropical storm as a former tropical cyclone. This generic term describes a cyclone that no longer possesses sufficient tropical characteristics to be considered a tropical cyclone. Post-tropical cyclones can continue carrying heavy rains and high winds. Note that former tropical cyclones that have become fully extratropical…as well as remnant lows…are two classes of post-tropical cyclones.
Last Advisory Issued by NHC
At 11 a.m. EDT (1500 UTC) on Sept. 25, the National Hurricane Center or NHC issued their final advisory on Leslie after the storm transitioned to a post-tropical storm. At that time the center of was located near latitude 31.6 degrees north and longitude 44.4 degrees west. Leslie is far from land areas. It is 1,080 miles (1,735 km) west-southwest of the Azores Islands. Maximum sustained winds remain near 35 mph (55 kph) with higher gusts.
The NHC said “Strengthening as a post-tropical cyclone is expected, and Leslie is forecast to become a large and powerful post-tropical cyclone by Wednesday with winds increasing to hurricane force on Thursday, Sept. 27.
Sep. 25, 2018 – NASA Sees Eastern Pacific’s Newest Tropical Storm Organizing
NASA provided an infrared look at newly developed Tropical Storm Rosa in the Eastern Pacific and found the storm was getting better organized.
NASA’s Aqua satellite passed over the Eastern Pacific early on Sept. 25 when Rosa was still a tropical depression called 20E. Infrared satellite data taken at 4:25 a.m. EDT (0825 UTC) on Sept. 25 from the Moderate Resolution Imaging Spectroradiometer or MODIS instrument aboard NASA’s Aqua satellite revealed strongest storms with the coldest cloud top temperatures around 20E’s center and in a band of thunderstorms southwest of center.
MODIS data showed that the tropical cyclone’s cloud pattern has become better organized, with developing convective banding features and the depression was upgraded to a tropical storm.
MODIS found coldest cloud tops had temperatures near minus 80 degrees Fahrenheit (minus 62.2 degrees Celsius). NASA research has found that cloud top temperatures that cold have the capability to generate heavy rainfall.
At 9 a.m. EDT (1200 UTC), the center of Tropical Strom Rosa was located near latitude 14.7 degrees north, longitude 108.0 degrees west. That’s about 385 miles (620 km) south-southwest of Manzanillo Mexico, so there are no coastal watches or warnings in effect. The depression is moving toward the west-northwest near 9 mph (15 kph). A west to west-northwest motion at a similar forward speed is expected during the next few days. Maximum sustained winds are near 45 mph (75 kph) with higher gusts.
NHC noted that conditions favor continued strengthening, with Rosa likely to remain in an environment of warm waters, low shear, and a very moist mid-level air mass for the next several days. Additional strengthening is likely, and Rosa could become a hurricane on Tuesday, Sept. 25.
Sep. 25, 2018 – Super Typhoon Trami’s Rainfall Examined By NASA/JAXA’s GPM Satellite
The Global Precipitation Measurement mission or GPM core observatory satellite probed super typhoon Trami when it traveled above the northwestern Pacific Ocean and provided an analysis of heavy rainfall and cloud top heights.
GPM, a joint satellite mission between NASA and the Japan Aerospace Exploration Agency, JAXA, flew over Trami on Sept. 24, 2018 at 8:03 a.m. EDT (1203 UTC). At that time Trami had maximum sustained winds estimated at 130 knots (150 mph). Rainfall measurements were made using data collected by GPM’s Microwave Imager (GMI) and Dual-Frequency Precipitation Radar (DPR) instruments. GPM’s GMI showed the locations of extremely heavy rainfall in the super typhoon’s well defined circular eye.
GPM’s radar (DPR Ku Band) coverage was limited because its swath only included storms on the western side of the typhoon. GPM’s DPR showed that rain was falling at a rate of over 120 mm (4.7 inches) per hour within intense storms in a strong feeder band well southwest of Trami’s eye.
The Joint Typhoon Warning Center (JTWC) used that GPM pass in an evaluation of super typhoon Trami. JTWC’s summary and analysis said that, “A 241201Z (Sept 24 at 8:01 a.m. EDT/1201 UTC) GPM 89GHZ microwave image clearly reveals an ongoing eyewall replacement cycle with concentric rings and a moat feature evident.”
On Sept. 25 at 5 a.m. EDT (0900 UTC) Super Typhoon Trami had maximum sustained winds near 155.4 mph (135 knots/250 kph). It was located near 19.9 degrees north latitude and 128.9 degrees east longitude, about 401 miles south of Kadena Air Base, Okinawa, Japan. Trami is moving slowly to the north-northeast. At that time, animated enhanced infrared satellite imagery depicts a symmetric eyewall surrounding a 35 nautical mile-wide oblong eye.
Trami will weaken very slowly as the storm crawls north. After two days, the system will speed up as it continues to weaken, eventually veering northeast. Trami is expected to still have winds of about 100 knots (115 mph) when it moves into the East China Sea northeast of Taiwan on September 29, 2018.