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.
Sep. 24, 2018 – NASA’s Terra Satellite Glares at the 37-Mile Wide Eye of Super Typhoon Trami
NASA’s Terra satellite provided a visible image of Super Typhoon Trami as it continued moving in a northwesterly direction in the Northwestern Pacific Ocean. Terra provided an amazing image of the large eye.
At 9:50 a.m. EDT (1350 UTC) on Sept. 24, the Moderate Resolution Imaging Spectroradiometer or MODIS instrument aboard NASA’s Terra satellite provided a visible-light image of Super Typhoon Trami in the North Western Pacific Ocean.
The MODIS image showed that Trami has a symmetric eyewall surrounding a 37 nautical-mile round eye.
At 11 a.m. EDT (1500 UTC) on Sept. 24 the center of Super Typhoon Trami was located near latitude 19.4 degrees north and longitude 129.5 degrees east. It is located 445 nautical miles south-southeast of Kadena Air Base, Okinawa Island, Japan.
The Joint Typhoon Warning Center noted that the storm is moving toward the wet-northwest and this general motion is expected to continue. Maximum sustained winds are near 149.6 mph (130 knots/240.8 kph) with higher gusts.
Trami is expected to peak at 167 mph (145 knots/268 kph) in the next day before beginning a weakening trend.
Sep. 24, 2018 – NASA’s Terra Satellite Finds Subtropical Storm Leslie Drifting in Central Atlantic
NASA’s Terra satellite provided a visible image of Subtropical Storm Leslie as it was meandering around the North Central Atlantic Ocean on Sept. 24, 2018.
At 9:50 a.m. EDT (1350 UTC) on Sept. 24, the MODIS instrument aboard NASA’s Aqua satellite looked at Leslie in visible light. The large subtropical cyclone continued to produce patches of deep convection, mostly to the south and east of the center.
MODIS also found a few new isolated thunderstorms developing near the surface center.
According to the National Hurricane Center, a Subtropical storm is a non-frontal low-pressure system that has characteristics of both tropical and extratropical cyclones. Like tropical cyclones, they are non-frontal, synoptic-scale cyclones that originate over tropical or subtropical waters, and have a closed surface wind circulation about a well-defined center. In addition, they have organized moderate to deep convection, but lack a central dense overcast. Unlike tropical cyclones, subtropical cyclones derive a significant proportion of their energy from baroclinic sources, and are generally cold-core in the upper troposphere, often being associated with an upper-level low or trough. 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 generally have a less symmetric wind field and distribution of convection.
At 11 a.m. EDT (1500 UTC) on Sept. 24 the center of Subtropical Storm Leslie was located near latitude 32.5 degrees north and longitude 48.0 degrees west. It is located far from land areas, and is about 1,240 miles (1,995 km) west of the Azores Islands.
The National Hurricane Center or NHC said the storm is moving toward the east near 5 mph (7 kph), and this general motion is expected to continue through Tuesday night. A turn toward the east-northeast with an increase in forward speed is forecast on Wednesday. Maximum sustained winds are near 40 mph (65 kph) with higher gusts. Little change in strength is forecast through tonight.
Leslie is forecast to strengthen by mid-week while it interacts and eventually merges with a frontal system.
Sep. 24, 2018 – Satellite Sees Short-lived Tropical Cyclone Kirk
Tropical Storm Kirk formed on Saturday, Sept. 22. By Monday, Sept. 24, Kirk lacked the closed circulation that is a prerequisite for tropical cyclone status. The NOAA-20 satellite provided a visible image of the storm at its peak.
On Sept. 23, 2018 at 10:42 a.m. EDT (1442) NOAA’s JPSS-1 (NOAA-20) satellite captured this visible image of Kirk at the height of its strength when it was a tropical storm with maximum sustained winds near 40 mph (65 kph). NOAA-20 is the second in a series of five polar-orbiting satellites to monitor the Earth’s atmosphere, land and oceans. NASA builds the JPSS series of satellites and NOAA operates them.
At 11 a.m. EDT (1500 UTC) on Sept. 24 the remnants of Kirk were located near latitude 10.0 degrees north and longitude 39.5 degrees west. That’s about 1,070 miles (1,725 km) west-southwest of the southernmost Cabo Verde Islands and about 1,470 miles (2,365 km) east of the Windward Islands.
The remnants are moving toward the west near 23 mph (37 kph) and this general motion is expected to continue over the next few days. Maximum sustained winds are near 40 mph (65 kph) with higher gusts. Little change in strength is forecast during the next 48 hours.
The remnants of Kirk will be monitored during the next few days in case regeneration into a tropical cyclone should occur.
Sep. 21, 2018 – NASA Sees Areas of Strength in Tropical Storm Trami
NASA’s Terra satellite provided an infrared look at Tropical Storm Trami, located just over 100 miles from Guam on Sept. 21. Infrared data provides temperature information that showed two areas of the highest, coldest cloud tops and most powerful storms within the tropical storm.
NOAA’s National Weather Service (NWS) in Tiyan, Guam said that a flash flood watch is in effect for all of Guam and the northern Marianas. A small craft advisory remains in effect until 6 a.m. CHST local time on Sunday, Sept. 23.
However, the Tropical Storm Watch for Rota, Tinian and Saipan has been canceled. Because Tropical Storm Trami (28W) continues to move away from the Marianas the threat of damaging winds has ended.
At 2:20 a.m. EDT (0230 UTC) on Sept. 13, Moderate Resolution Imaging Spectroradiometer or MODIS instrument aboard NASA’s Aqua satellite analyzed Hurricane Florence in infrared light. MODIS found coldest cloud top temperatures in two large areas. One was around the center of circulation and the other was in a thick band of thunderstorms wrapping into the low-level center. Those temperatures were as cold as or colder than minus 80 degrees Fahrenheit (minus 112 degrees Celsius). Surrounding them were powerful 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.
On Sept. 21, Trami was located near latitude 15.3 degrees north and longitude 142.9 degrees east. That’s about 175 miles west-northwest of Rota and about 180 miles northwest of Guam. Trami is moving northwest at 12 mph. It is expected to make a slight turn toward the west-northwest with little change in forward speed over the next 24 hours. Maximum sustained winds have increased to 40 mph. 28W is forecast to intensify through Saturday. Tropical storm force winds extend outward from the center up to 120 miles.
NWS issued a special weather statement for Micronesia that said areas of heavy showers and thunderstorms can be found near Trami and in the monsoon flow southwest of the storm. The westerly monsoonal flow across Yap State and the Republic of Palau will increase during the next few days. Showery weather and locally gusty winds are likely for Yap and Koror through this weekend. Sea and surf conditions may become hazardous at times.