Leslie (Atlantic Ocean) 2018

Oct. 03, 2018 – NASA Sees Atlantic’s Leslie Become a Hurricane

NASA’s Aqua satellite captured an infrared image of Hurricane Leslie that revealed strong storms circled the center.

Aqua image of Leslie
At 1:55 a.m. EDT (0555 UTC) on Oct. 3, the MODIS instrument that flies aboard NASA’s Aqua satellite gathered infrared data on Hurricane Leslie. Strongest thunderstorms circled the center and were in a thick band northeast of center where cloud top temperatures were as cold as minus 63 degrees Fahrenheit (minus 53 Celsius). Credit: NASA/NRL

At 1:55 a.m. EDT (0555 UTC) on Oct. 3 the MODIS instrument that flies aboard NASA’s Aqua satellite gathered infrared data on Leslie. Infrared data provides temperature information. Strongest thunderstorms were fragmented as they circled the center and were in a thick band northeast of center where MODIS found cloud top temperatures as cold as minus 63 degrees Fahrenheit (minus 53 Celsius). NASA research has shown that cloud tops with temperatures that cold were high in the troposphere and have the ability to generate heavy rain.

The National Hurricane Center or NHC noted “Deep convection surrounding the center of Leslie has become better organized overnight, with the development of a ragged eye in infrared satellite images.”  A microwave image revealed a well-defined low-level eye with a ring of broken convection surrounding it.

At 5 a.m. EDT (0900 UTC), the center of Hurricane Leslie was located near latitude 29.6 degrees north and longitude 56.9 degrees west. That’s about 505 miles (810 km) east-southeast of Bermuda. Leslie is nearly stationary, and little motion is expected today.  A northward motion is forecast to begin tonight, and this motion should continue through Friday night. Maximum sustained winds have increased to near 75 mph (120 kph) with higher gusts.  Some additional strengthening is forecast during the next day or so.

NHC noted “The hurricane is forecast to remain within favorable environmental conditions consisting of warm water and low vertical wind shear over the next day or two.  These conditions should allow for some additional strengthening.”

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

By Rob Gutro
NASA’s Goddard Space Flight Center

 

Kong-rey (Northwestern Pacific Ocean)

Oct. 02, 2018 – NASA Eyes Powerful Super Typhoon Kong-Rey

NASA’s Aqua satellite provided an infrared view of Super Typhoon Kong-Rey as it continued tracking through the Northwestern Pacific Ocean. Another Super typhoon, Trami, passed through the same area one week ago and cooler waters it left in its wake are expected to affect Kong-Rey.

Aqua image of Kong-rey
NASA’s Aqua satellite passed over Super Typhoon Kong-Rey on Oct. 2 at 12:35 a.m. EDT (0435 UTC) and analyzed it in infrared light. Powerful storms circled a clear eye (purple). Credit: NASA JPL, Heidar Thrastarson

NASA’s Aqua satellite passed over Super Typhoon Kong-Rey on Oct. 2 at 12:35 a.m. EDT (0435 UTC) and the Atmospheric Infrared Sounder or AIRS instrument aboard analyzed cloud top temperatures in infrared light. Coldest cloud top temperatures were being pushed northeast of center and were as cold as or colder than 208 Kelvin (minus 85.2 degrees Fahrenheit/minus 65.1 Celsius). Cloud top temperatures that cold indicate strong storms that have the capability to create heavy rain.

The Joint Typhoon Warning Center noted at 11 a.m. EDT (1500 UTC), “Animated enhanced infrared satellite imagery shows Kong-Rey has maintained a well-defined eye with deep convection wrapping around it. However, the deep convection [strong development of thunderstorms] has become slightly less symmetric over the past several hours, especially in the northeast quadrant.

The center of Super Typhoon Kong-Rey was located near latitude 19.2 degrees north and longitude 130.9 degrees east. Kong-Rey is currently about 493 nautical miles south-southeast of Kadena Air Base, Okinawa Island, Japan. Kong-Rey is moving toward the northwest. Maximum sustained winds have decreased to near 155 mph (250 kph/135 knots).

Kong-Rey will continue to encounter cooler sea surface temperatures by Oct. 3 which are a result of upwelling (bringing cooler water from the ocean bottom to the surface) produced by Super Typhoon Trami which passed through the area several days ago.

By Rob Gutro
NASA’s Goddard Space Flight Center

 

Walaka (Central Pacific Ocean)

Oct. 02, 2018 – NASA Sees a Lot of Strength in Infrared View of Cat 4 Hurricane Walaka

Infrared satellite imagery provides temperature data, and when NASA’s Aqua satellite passed over the Central Pacific Ocean, it analyzed Hurricane Walaka. Walaka is a Category 4 Hurricane on the Saffir-Simpson Hurricane Wind Scale.

Aqua image of Walaka
On Oct. 2 at 9:30 a.m. EDT (1330 UTC) NASA’s Aqua satellite revealed cloud top temperatures in strongest storms around Walaka’s center and in a fragmented band of thunderstorms east of the center of circulation. Those temperatures were as cold as or colder than minus 70 degrees (red) Fahrenheit (minus 56.6 degrees Celsius). Credit: NASA/NRL

Cloud top temperatures determine strength of the thunderstorms that make up a tropical cyclone. The colder the cloud top, the stronger the uplift in the storm that helps thunderstorm development. Basically, infrared data helps determine where the most powerful storms are within a tropical cyclone.

The Moderate Resolution Imaging Spectroradiometer or MODIS instrument aboard Aqua provided that infrared data on Oct. 2 at 9:30 a.m. EDT (1330 UTC) MODIS data showed cloud top temperatures in strongest storms around Walaka’s center and in a fragmented band of thunderstorms east of the center of circulation. They were as cold as or colder than minus 70 degrees Fahrenheit (minus 56.6 degrees Celsius). NASA research indicates very cold cloud tops with the potential to generate very heavy rainfall.

On Oct. 2, a Hurricane Warning was in effect for the Johnston Atoll and a Hurricane Watch is in effect for Papahanaumokuakea Marine National Monument from Nihoa to French Frigate Shoals to Maro Reef.

At 5 a.m. HST/11 a.m. EDT/1500 UTC, the center of Hurricane Walaka was located near latitude 14.7 degrees north and longitude 170.0 degrees west. Walaka is moving toward the north near 10 mph (17 kph). This general motion is expected to continue through Wednesday night with a steady increase in forward speed. On the forecast track, the center of Walaka is expected to pass just to the west of Johnston later today.

NOAA’s Central Pacific Hurricane Center noted “Maximum sustained winds are near 155 mph (250 kph) with higher gusts.  Walaka is a category 4 hurricane on the Saffir-Simpson Hurricane Wind Scale. Little change in intensity is expected through tonight, with rapid weakening expected Wednesday and Wednesday night.”

For updated forecasts, visit: http://www.prh.noaa.gov/cphc

By Rob Gutro
NASA’s Goddard Space Flight Center

 

Leslie (Central Atlantic Ocean)

Oct. 02, 2018 – NASA Soaks Up Tropical Storm Leslie’s Water Vapor Concentration

When NASA’s Aqua satellite passed over the Central Atlantic Ocean on Oct. 2 the MODIS instrument aboard analyzed water vapor within Tropical Storm Leslie.

Aqua image of Leslie
NASA’s Aqua satellite passed over Tropical Storm Leslie in the Central Atlantic Ocean on Oct. 2 at 1:15 a.m. EDT (0515 UTC). The MODIS instrument showed highest concentrations of water vapor (brown) and coldest cloud top temperatures circled the center with a gap in the north-northeastern quadrant. 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 the stronger they are.

NASA’s Aqua satellite passed over Tropical Storm Leslie in the Central Atlantic Ocean on Oct. 2 at 1:15 a.m. EDT (0515 UTC) and the Moderate Resolution Imaging Spectroradiometer or MODIS instrument gathered water vapor content and temperature information. The storm continues to have a ragged banded eye.

The MODIS image showed highest concentrations of water vapor and coldest cloud top temperatures circled the center with the exception of the north-northeastern quadrant. MODIS saw coldest cloud top temperatures were as cold as minus 70 degrees Fahrenheit (minus 56.6 degrees Celsius) in those areas. Storms with cloud top temperatures that cold have the capability to produce heavy rainfall.

Leslie remains far enough from land areas so that there are no warnings or watches in effect. At 11 a.m. EDT (1500 UTC), the center of Tropical Storm Leslie was located near latitude 30.9 degrees north and longitude 56.1 degrees west. That’s 520 miles (840 km) east of Bermuda.  Leslie is moving toward the southwest near 8 mph (13 kph). Maximum sustained winds remain near 65 mph (100 kph) with higher gusts.

The National Hurricane Center or NHC forecast noted “Gradual strengthening is expected during the next day or two, and Leslie is forecast to become a hurricane tonight or on Wednesday, Oct. 3.”

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

By Rob Gutro
NASA Goddard Space Flight Center

 

Rosa (Eastern Pacific Ocean)

Oct. 04, 2018 – Rosa’s Rainfall (from Earth Observatory)

Peaking as a category 4 hurricane on September 28, 2018, over the Eastern Pacific Ocean, Hurricane Rosa weakened before making landfall on the Baja California Peninsula four days later. Still, as the storm’s remnants moved inland, they delivered heavy rain and caused flash floods in northwestern Mexico and the U.S. Southwest.

Rosa's rainfall

“We can draw parallels between this storm and Hurricane Florence,” said Gary Partyka, an atmospheric scientist with the GMAO at NASA’s Goddard Space Flight Center. “The strength of both weakened tremendously, but both moved enough moisture to produce substantial amounts of rainfall. A hurricane’s category (which describes its maximum winds) is not very important when it comes to flooding.”

The still image and animation above show the atmosphere’s total precipitable water. That is, the depth of water in a column of the atmosphere if all the water in that column fell as rain. The image and animation, compiled from October 1-3, 2018, were created with data from a version of a NASA model known as the Goddard Earth Observing System Data Assimilation System (GEOS DAS), which uses satellite data and mathematical representations of physical processes to calculate what was happening in the atmosphere.

Viewed globally, the model shows large circulation patterns as well as individual storms. This regional view shows Hurricane Rosa as it spun over the East Pacific Ocean and broke up over Baja California and the U.S. Southwest. Dark blue areas represent the highest values of precipitable water.

Partyka says it is important to note that not all precipitable water falls as rain; some water vapor stays behind in the atmosphere. Nor is it a limit on the amount of rain that can fall, which can increase as water vapor moves into the column of air.

“The indicator is useful for showing potential regions where rainfall could be excessive, though you also need a trigger to make the ‘precipitable water’ fall as precipitation,” Partyka said. In this case, Rosa’s remnants and a low-pressure system off the California coast did serve as triggers.

According to the National Weather Service, October 2 was the wettest October day on record in Phoenix, Arizona. More than 2 inches (5 centimeters) of rainfall were measured that day at Phoenix Sky Harbor International. The last time the city saw more than two inches in a day in October was in 1988.

NASA Earth Observatory imagery by Joshua Stevens, using GEOS-5 data from the Global Modeling and Assimilation Office at NASA GSFC. Story by Kathryn Hansen.

Oct. 02, 2018 – NASA’s Aqua Satellite Shows Rosa’s Remnants Soaking Arizona

NASA provided an infrared view of Tropical Depression Rosa’s remnants that showed strongest storms with heaviest rainfall potential were over east central Arizona on Oct. 2. The National Hurricane Center noted that although Rosa had dissipated by 11 a.m. EDT on Oct. 2, the threat of heavy rains and flash flooding continues over the Desert Southwest.

Aqua image of Rosa
On Tuesday, Oct. 2 at 6:05 a.m. EDT (1005 UTC), the MODIS instrument aboard NASA’s Aqua satellite looked at the remnants of tropical depression Rosa in infrared light revealing the storm soaking Arizona. MODIS found coldest cloud tops (yellow) had temperatures near minus 63 degrees Fahrenheit (minus 53 degrees Celsius) which indicated powerful rain-making storms. Credit: NASA/NRL

NOAA’s National Weather Service Weather Prediction Center in College Park, Md. noted “Heavy tropical rain from Rosa will bring flash flood threats to the Desert Southwest and Four Corners region over the next couple of days. Flood Watches are in effect for multiple states, including California, Arizona, Nevada, Utah, Colorado and Idaho. There is also a moderate risk of excessive rain for central portions of Arizona.”

Infrared satellite data captured on Tuesday, Oct. 2 at 6:05 a.m. EDT (1005 UTC the Moderate Resolution Imaging Spectroradiometer or MODIS instrument aboard NASA’s Aqua satellite revealed the location of strongest storms with the coldest cloud top temperatures. 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.

Satellite images and surface observations indicate that Rosa has become a trough or an elongated area of low pressure with multiple swirls along its axis. Therefore, Rosa no longer qualifies as a tropical cyclone.

That heavy rainfall potential that NASA’s infrared data showed are reflected in the forecast today, Oct. 2 and tomorrow, Oct. 3. In Baja California and northwestern Sonora, 3 to 6 inches are forecast with isolated 10 inches. In central and southern Arizona 2 to 4 inches are forecast with isolated 6 inch totals are possible in the mountains of central Arizona. For the rest of the Desert Southwest, Central Rockies, and Great Basin, the National Hurricane Center forecast expects between 1 to 2 inches, with isolated totals to 4 inches. These rainfall amounts may produce life-threatening flash flooding. Dangerous debris flows and landslides are also possible in mountainous terrain.

At 11 a.m. EDT (1500 UTC), the remnants of Rosa were located near latitude 29.7 degrees north and longitude 114.2 degrees west. That’s about 95 miles (155 km) south-southeast of San Felipe, Mexico. The remnants are moving toward the northeast near 8 mph (13 kph), and they are expected to move over the Desert Southwest by tonight. Maximum sustained winds are near 30 mph (45 kph) with higher gusts.

For local forecasts, visit: www.weather.gov

By Rob Gutro
NASA Goddard Space Flight Center

Sergio (Eastern Pacific Ocean)

Oct. 02, 2018 – NASA Finds Tropical Storm Sergio on the Verge of Hurricane Status

The National Hurricane Center noted that Tropical Storm Sergio was on the verge of becoming a hurricane in the Eastern Pacific Ocean and NASA’s Aqua satellite confirmed very powerful storms within.

Aqua image of Sergio
Infrared satellite data captured at 5:30 a.m. EDT (0930 UTC) on Oct. 1 from NASA’s Aqua satellite revealed strongest storms with the coldest cloud top temperatures west of Sergio’s center and in a band of thunderstorms southwest of the center. MODIS found coldest cloud tops had temperatures near minus 70 degrees Fahrenheit (minus 56.6 degrees Celsius). Credit: NASA/NRL

Infrared satellite data captured at 5:30 a.m. EDT (0930 UTC) on Oct. 1 from the Moderate Resolution Imaging Spectroradiometer or MODIS instrument aboard NASA’s Aqua satellite revealed strongest storms with the coldest cloud top temperatures west of Sergio’s center and in a band of thunderstorms southwest of the center.  MODIS found coldest cloud tops had temperatures near minus 70 degrees Fahrenheit (minus 56.6 degrees Celsius). NASA research has found that cloud top temperatures that cold have the capability to generate heavy rainfall.

At 11 a.m. EDT, the National Hurricane Center or NHC noted “Sergio is almost a hurricane. Satellite images indicate that the central convection has been increasing in intensity during the past several hours, but there are still no indications of an eye in that data.  Microwave imagery does show an eye feature, however. The outer bands are not particularly well organized, and there are some dry slots beyond the inner core.”

The center of Tropical Storm Sergio was located near latitude 11.5 degrees north and longitude 109.5 degrees west.  Sergio is far from land, so there are no coastal advisories in effect. It is about 625 miles (1,000 km) southwest of Manzanillo, Mexico. Sergio is moving toward the west near 14 mph (22 kph), and this general motion is forecast to continue through tonight.  A turn toward the west-northwest is expected on Tuesday. Maximum sustained winds remain near 70 mph (110 kph) with higher gusts.

NHC noted that “Strengthening is expected during the next 48 hours, and Sergio is forecast to become a hurricane later today, and a major hurricane by Wednesday, Oct. 3.”

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

By Rob Gutro (with information from the NHC)
NASA Goddard Space Flight Center

Kong-rey (Northwestern Pacific Ocean)

Oct. 01, 2018 – Typhoon Kong-rey Moving through Northwestern Pacific

At 11 am EDT (1500 UTC) on Oct 1 , Kong-rey was located near 16.8 north and 134.4 east, about 488 miles north-northwest of Yap. It was moving to the northwest and had maximum sustained winds near 125 knots gusting to 150 knots.  Currently the only threatened landmasses are the Ryuku Islands.

Worldview image of Kong-rey
Satellites captured this worldview image of Typhoon Kong-rey on September 30, 2018. Courtesy: NASA Worldview, Earth Observing System Data and Information System (EOSDIS).

This satellite image was taken on September 30, 2018 by NASA’s Earth Observing System Data and Information System (EOSDIS) Worldview application which 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. ”

Kong-rey will move northwest, intensifying steadily. The storm will peak at 135 knots later today, after which it will steadily weaken. The system will gradually veer north, into the Yellow Sea after three days.

By Rob Gutro
NASA’s Goddard Space Flight Center

Walaki (Central Pacific Ocean)

Oct. 01, 2018 – NASA Sees Walaka Becoming a Powerful Hurricane

The Global Precipitation Measurement mission or GPM core satellite passed over the Central Pacific Hurricane Center and analyzed Walaka’s rainfall and cloud structure as it was strengthening into a hurricane.

GPM image of Walaka
On Sept. 30, GPM data revealed intense convective storms in a large feeder band wrapping around the Tropical Storm Wakala’s northeastern side where rain was falling at a rate of almost 6.5 inches (165 mm) per hour in the intense storms in the feeder band northeast of Walaka’s center of circulation. . A tall convective storm was located in a line northwest of Walaka’s center. It was found by DPR to reach heights above 8.5 miles (13.7 km). Credit; NASA/JAXA, Hal Pierce

Walaka formed southwest of the Hawaiian Islands on Saturday, Sept. 29. At 5 p.m. HST on Sunday, Sept. 30, Walaka strengthened to a hurricane.

The GPM core observatory recently had a couple good looks at tropical storm Walaka as it was intensifying into a powerful hurricane. GPM passed directly over tropical storm Walaka when it was located south of the Hawaiian islands on September 30, 2018 at 8:38  a.m. HST (1838 UTC).

On Sept. 30, GPM data revealed intense convective storms in a large feeder band wrapping around the Tropical Storm Wakala’s northeastern side  where rain was falling at a rate of almost 6.5 inches (165 mm) per hour in the intense storms in the feeder band northeast of Walaka’s center of circulation.  A tall convective storm was located in a line northwest of Walaka’s center. It was found by DPR to reach heights above 8.5 miles (13.7 km). Credit: NASA/JAXA, Hal Pierce

Data collected by GPM’s Microwave Imager (GMI) and Dual-Frequency Precipitation Radar (DPR) instruments showed that Walaka was well organized and very close to hurricane intensity. GPM’s Radar (DPR Ku Band) data revealed intense convective storms in a large feeder band that was wrapping around the tropical storm’s northeastern side and storms wrapping around a forming eye wall. GPM’s DPR found rain falling at a rate of almost 6.5 inches (165 mm) per hour in the intense storms in the feeder band northeast of Walaka’s center of circulation.

Walaka had strengthened to hurricane intensity when GPM flew above about twelve hours later at 8:07 p.m. HST (Oct. 1, 2018 at 0607 UTC). Walaka had developed an eye and was undergoing rapid intensification. The intensifying hurricane is passing well to the south of the Hawaiian Islands.

The GPM satellite’s   Dual-Frequency Precipitation Radar (DPR) data were used to show the structure of precipitation within intensifying tropical storm Walaka. The simulated 3D view of Walaka, looking from the southwest, showed storm tops of powerful storms wrapping into the center of the tropical storm. A tall convective storm was located in a line northwest of Walaka’s center. It was found by DPR to reach heights above 8.5 miles (13.7 km). GPM is a joint mission between NASA and the Japanese space agency JAXA.

On Monday, October 1, 2018, NOAA’s Central Pacific Hurricane Center or CPHC noted that a Hurricane Warning is in effect for Johnston Atoll. Also, interests in the Papahanaumokuakea Marine National Monument should monitor the progress of Walaka.

At 5 p.m. HST/11 p.m. EDT (0300 UTC, Oct. 1) on Sept. 30 or , the center of Hurricane Walaka was located near latitude 11.9 degrees north and longitude 166.4 degrees west. Walaka is moving toward the west near 12 mph (19 kph) and this motion is expected to slow and become northwest on Monday, then north on Tuesday. Maximum sustained winds are near 75 mph (120 kph) with higher gusts. Rapid intensification is forecast through Tuesday.

The Joint Typhoon Warning Center (JTWC) predicts that Hurricane Walaka will continue to strengthen and re-curve to the north later today. Walaka is expected to be a powerful category four hurricane on the Saffir-Simpson wind scale when it passes just to the west of Johnson Atoll in a couple days. Walaka is not expected to have a significant effect on the Hawaiian Islands.

By Hal Pierce / Rob Gutro
NASA’s Goddard Space Flight Center

Trami (Northwestern Pacific Ocean)

Oct. 01, 2018 – Satellite Sees Extra-Tropical Cyclone Trami Moving Past Japan

NOAA’s NOAA-20 satellite captured a visible image of Typhoon Trami on Oct. 1 after it had become extra-tropical and moved away from Japan.

JPSS VIIRS image of Trami
On Oct. 1 at 11:54 p.m. EDT (Sept. 30 at 0354 UTC) the VIIRS instrument aboard NOAA’s NOAA-20 polar orbiting satellite provided a visible image of Trami. The imagery showed the storm’s circulation had eroded quickly and was being blown apart by winds. On Oct. 1, Trami passed Hokkaido and had become extra-tropical. Credit: NOAA/NRL

At 11 a.m. EDT (1500 UTC) on Sunday, Sept. 30, the Joint Typhoon Warning Center issued the final advisory on the system. At that time, Typhoon Trami was located about 157 miles west-southwest of Camp Fuji, Japan and moving northeast at 28 knots (32 mph/52 kph). Maximum sustained winds were near 75 knots (86 mph/139 kph). Trami was weakening rapidly and becoming extra-tropical as it tracked very rapidly over Honshu.

On Oct. 1 at 11:54 p.m. EDT (Sept. 30 at 0354 UTC) the VIIRS instrument aboard NOAA’s NOAA-20 polar orbiting satellite provided a visible image of Trami. The imagery showed the storm’s circulation had eroded quickly and was being blown apart by winds. By Oct. 1, Trami passed Hokkaido and had become extra-tropical.

For updates from the Japan Meteorological Agency, visit: http://www.jma.go.jp/en/typh/

By Rob Gutro
NASA’s Goddard Space Flight Center

Rosa (Eastern Pacific Ocean)

Oct. 01, 2018 – NASA’s Infrared Vision Reveals Rosa’s Extent into the U.S. Southwest

Hurricane Rosa continued weakening as NASA’s Aqua satellite passed overhead and collected temperature information. Satellite data showed that Rosa’s center still off-shore from northwestern Mexico, but its clouds and rains had already stretched into Arizona and infrared data showed that rainfall potential.

AIRS image of Rosa
NASA’s Aqua satellite provided an infrared picture of Tropical Storm Rosa’s cloud top temperatures from Oct. 1 at 5:23 a.m. EDT (0923 UTC). Rosa’s center was still off-shore from northwestern Mexico, but its clouds and rains had already stretched into Arizona and infrared data showed that rainfall potential. Credit: NASA JPL, Heidar Thrastarson

National Hurricane Center (NHC) said a Tropical Storm Warning is in effect for the west coast of the Baja California peninsula from Punta Abreojos to Cabo San Quintin. A Tropical Storm Watch is in effect for the east coast of the Baja California peninsula from Bahia de los Angeles to San Felipe. Interests elsewhere in the northern and central Baja California peninsula and northwestern Sonora should monitor the progress of Rosa.

The Atmospheric Infrared Sounder or AIRS instrument aboard NASA’s Aqua satellite passed over Tropical Storm Rosa on Oct. 1 at 5:23 a.m. EDT (0923 UTC). and analyzed the storm in infrared light. Infrared light provides temperature data and that’s important when trying to understand how strong storms can be. The higher the cloud tops, the colder and the stronger they are.

When Aqua passed over Rosa, the AIRS instrument found coldest cloud top temperatures in thunderstorms mostly northeast the center where temperatures were as cold as minus 63 degrees Fahrenheit (minus 53 degrees Celsius). Those storms were stretching over northwestern Mexico and into Arizona. Storms with cloud top temperatures that cold have the capability to produce heavy rainfall.

At 11 a.m. EDT (1500 UTC), NHC noted the center of Tropical Storm Rosa was located near latitude 27.5 degrees west and longitude 116.5 degrees west. That’s 90 miles (140 km) west-southwest of Punta Eugenia, Mexico. Rosa is moving toward the north-northeast near 12 mph (19 km/h), and this general motion is expected to continue through Tuesday, Oct. 2. Maximum sustained winds are near 45 mph (75 kph) with higher gusts. Some weakening is forecast during the next 48 hours.  Weakening is forecast through tonight while Rosa approaches and moves over the northern Baja California peninsula.

On the forecast track, the center of Rosa will approach the central and northern Baja California peninsula later today, Oct. 1 and then move across the peninsula into the northern Gulf of California tonight.  Rosa’s remnants are then expected to move across the Desert Southwest on Tuesday, Oct. 2. Rosa is expected to become a remnant low over the southwestern United States on Tuesday.

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

For local forecasts and impacts in the U.S., visit: www.weather.gov.

By Rob Gutro
NASA’s Goddard Space Flight Center