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Hurricane Season 2010: Hurricane Otto (Atlantic Ocean)
10.08.10
 
October 8, 2010

NASA Sees Otto Become Eighth Hurricane of the Atlantic Season

GOES-13 visible image of Hurricane Otto, showing the large band of showers and thunderstorms › View larger image
GOES-13 visible image of Hurricane Otto at 0245 UTC (10:45 p.m. EDT) on Oct. 7, showing the large band of showers and thunderstorms extending from its southeastern quadrant and raining on the northern Leeward Islands, Virgin Islands, Puerto Rico and the eastern Dominican Republic. The U.S. east coast is seen to the far left in the image.
Credit: NOAA/NASA GOES Project
Note the large band of strong thunderstorms extending from the southeast of Otto's circulation › View larger image
This infrared image of Hurricane Otto's cold (purple and blue) thunderstorms was taken from NASA's Aqua satellite on Oct. 7 at 1729 UTC (1:29 p.m. EDT). The purple areas indicate highest, coldest thunderstorm cloud tops colder than -65 Fahrenheit. Note the large band of strong thunderstorms extending from the southeast of Otto's circulation, raining on the northern Leewards, the Virgin Islands, and Puerto Rico.
Credit: NASA/JPL, Ed Olsen
At 11 a.m. EDT on Oct. 8, Otto strengthened into a hurricane, becoming the eighth hurricane of the Atlantic Ocean season. NASA's Aqua satellite and the NOAA GOES-13 satellite captured images of Otto as he intensified.

Otto had maximum sustained winds near 75 mph, and the National Hurricane Center in Miami, Fla. noted that some strengthening is possible before it weakens on Saturday, Oct. 9. Otto was located about 445 miles south of Bermuda near 25.9 North and 64.0 West. It was moving east-northeast near 17 mph, and had a minimum central pressure of 979 millibars.

On Oct. 7 at 1729 UTC (1:29 p.m. EDT) NASA's Aqua satellite passed over Otto and the Atmospheric Infrared Sounder (AIRS) instrument captured an infrared image of its cloud temperatures. The image showed that the highest, coldest thunderstorm cloud tops colder than -65 Fahrenheit were around Otto's center and throughout the large band of strong thunderstorms extending from the southeast of Otto's circulation. That band of strong thunderstorms brought heavy rainfall on the already soaked areas of the northern Leeward Islands, the Virgin Islands, and Puerto Rico.

This morning, Otto developed a well-defined center, covered by dense overcast. There's a large curved band of showers and thunderstorms over the southeastern quadrant which continues to bring the heavy rainfall to the northern Leeward Islands, Virgin Islands, Puerto Rico and Dominican Republic today.

That large band of showers and thunderstorms extending from Otto's southeastern quadrant was apparent on infrared imagery from the Geostationary Operation Environmental Satellite, GOES-13 early today at 0245 UTC (10:45 p.m. EDT on Oct. 7).GOES satellites are operated by NOAA, and images and animations of GOES satellite data are created by the NASA GOES Project at NASA's Goddard Space Flight Center, Greenbelt, Md.

Because Hurricane Otto is expected to remain in an environment with light wind shear and warm waters for about 24 hours (until 11 a.m. EDT Saturday, Oct. 9), it is expected to strengthen during that time. After mid-day Saturday (eastern daylight time) Otto will run into increasing winds shear from the southwest and it will move into cooler waters. Sea surface temperatures of at least 80 degrees Fahrenheit are needed to maintain a tropical cyclone (hurricane).

Over the weekend as Otto weakens it will begin transition into an extratropical storm.

Text credit: Rob Gutro
NASA's Goddard Space Flight Center/, Greenbelt, Md.



October 7, 2010

NASA Satellites See Otto Become a Tropical Storm

TRMM indicated that convection in the center of the storm was generating thunderstorms. › View larger image
The TRMM satellite passed above Otto on Oct. 7 at 0945 UTC (5:45 a.m. EDT) and the TRMM Precipitation Radar data revealed a feeder band in the southern part of the storm was dropping moderate to heavy (red) rainfall. The TRMM Microwave Imager indicated that convection in the center of the storm was generating thunderstorms.
Credit: NASA/SSAI, Hal Pierce
Otto is seen as the rounded area in the bottom center of this AIRS microwave image. › View larger image
Microwave images are created when data from NASA's Aqua satellite AIRS and AMSU instruments are combined. The cold areas (yellow-green) in this Oct. 7 image (at 2:29 a.m. EDT) indicate where there is precipitation or ice in the cloud tops. The microwave image suggests cold, high thunderstorms. The cloud tops were as cold as -80 Celsius (-112 Fahrenheit) over the center of Otto. Otto is seen as the rounded area in the bottom center of this image.
Credit: NASA/JPL, Ed Olsen
NASA satellites have collected data as the Atlantic Ocean's Tropical Depression 17 has undergone two changes in less than 24 hours. Since Oct. 6, the depression has strengthened and has tropical storm-force winds and has morphed from a sub-tropical storm into a tropical storm.

After a United States Air Force Reserve reconnaissance flight subtropical depression seventeen was upgraded by the National Hurricane Center (NHC) to subtropical storm Otto on Oct. 6 at 5 p.m. EDT (2100 UTC). On Oct. 6 and 7, NASA's TRMM and Aqua satellites were flying overhead measuring very cold, high thunderstorm cloud tops and heavy rainfall.

The Tropical Rainfall Measuring Mission (TRMM) satellite is managed by NASA and the Japanese Space Agency. At NASA's Goddard Space Flight Center in Greenbelt, Md., meteorologists create satellite imagery from TRMM data. When TRMM passed above Otto this morning, Oct. 7 at 0945 UTC (5:45 a.m. EDT) the TRMM Precipitation Radar data revealed a feeder band in the southern part of the storm was dropping moderate to heavy rainfall (falling at a rate as much as 2 inches per hour). Coverage from TRMM Microwave Imager data indicated that convection in the center of the storm was generating thunderstorms.

At 11 a.m. EDT on Oct. 7, Tropical Storm Otto had maximum sustained winds near 60 mph, and strengthening is likely, according to the National Hurricane Center. Otto could become a hurricane in the next day or two. Otto was located about 255 miles northeast of Grand Turk Island or 620 miles south-southwest of Bermuda near 23.8 North latitude and 68.0 West longitude. Otto is far away enough from any land areas that there are no watches or warnings in effect. Otto was slowly trudging through the Atlantic Ocean at 2 mph and moving northeast. Otto's minimum central pressure was 992 millibars.

Forecasters at the NHC said that "Otto has finally transitioned into a tropical cyclone based on an analysis of vertical temperatures on Oct. 7 at 0935 UTC (5:35 a.m. EDT)" from the University of Wisconsin-Cooperative Institute for Meteorological Satellite Services (CIMSS). CMISS analyzed data from the Advanced Microwave Sounding Unit (AMSU) instrument. AMSU is a multi-channel microwave radiometer installed on a number of satellites, including NASA's Aqua satellite and NOAA polar orbiting satellites. The AMSU instrument examines several bands of microwave radiation from the atmosphere to provide data on temperature and moisture levels throughout a tropical cyclone. CIMSS utilizes NASA satellite data and offers real-time and archived tropical cyclone products from it home (web) page. The AMSU data indicated that the warm core of Otto had "moved upward" from the mid-levels of the storm to the upper-levels, re-classifying the storm as "tropical" instead of "sub-tropical."

Data from NASA's Atmospheric Infrared Sounder (AIRS) instrument also helped confirm the transition into a tropical storm. AIRS is an instrument that also flies aboard NASA's Aqua satellite. AIRS imagery showed a recent burst of deep convection, where the cloud top temperatures were near -80 Celsius (-112 Fahrenheit) over the center of Otto.

Microwave images are created when data from NASA's Aqua satellite AIRS and AMSU instruments are combined. A microwave image from data at 2:29 a.m. EDT on October 7 was created at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The image indicated there was a large area of precipitation or ice in the cloud tops in Tropical Storm Otto.

Otto is meandering around, but a large trough (an elongated area of low pressure) that is along the U.S. East Coast is expected to continue moving east and push Otto into the open waters of the Atlantic over the next couple of days.

Text credit: Rob Gutro
NASA's Goddard Space Flight Center/, Greenbelt, Md.



October 6, 2010

Two NASA Satellites See Subtropical Storm 17 Strengthening

The TRMM satellite passed over TD17 on Oct. 6 at 5 a.m. EDT when it was just classified as a sub-tropical storm. › View larger image
The TRMM satellite passed over TD17 on Oct. 6 at 5 a.m. EDT when it was just classified as a sub-tropical storm. The yellow and green areas indicate moderate rainfall between .78 to 1.57 inches per hour. Red areas are considered heavy rainfall at almost 2 inches per hour.
Credit: NASA/SSAI, Hal Pierce
AIRS captured this infrared image of its cold (as cold as -63F or colder) cloud-top temperatures in purple. › View larger image
NASA's Aqua satellite passed over Tropical Depression 17 on October 6 at 05:47 UTC (1:47 a.m. EDT) and captured this infrared image of its cold (as cold as -63F or colder) cloud-top temperatures in purple. The extent of TD17's cloud cover stretches over the northern Leeward Islands and Puerto Rico.
Credit: NASA/JPL, Ed Olsen
Subtropical Storm 17 is giving signs of strengthening according to NASA satellite data. NASA's TRMM and Aqua satellites captured rainfall and cloud temperature data that provided forecasters with signs that the depression was getting better organized.

When the National Hurricane Center in Miami, Fla. classified the low pressure area formerly known as System 97L as "sub-tropical storm 17" (TD17)at 5 a.m. EDT this morning, Oct. 6, the Tropical Rainfall Measuring Mission (TRMM) satellite was almost directly above it in orbit around the Earth. TRMM is a satellite that can estimate rainfall, and is managed by both NASA and the Japanese Space Agency.

TRMM passed above TD17 at 10:41 UTC (6:41 a.m. EDT) collecting those rainfall data. TRMM Precipitation Radar (PR) data clearly revealed that TD17 had very heavy rainfall within powerful convective thunderstorms.

When NASA's Aqua satellite flew over the storm from space on October 6 at 05:47 UTC (1:47 p.m. EDT), the Atmospheric Infrared Sounder (AIRS) instrument aboard the spacecraft captured infrared imagery of its cloud-top temperatures. At that time, cloud tops that were as cold as or colder than -63F, but they've cooled since then. Cooling cloud tops indicate cloud tops are higher than they were before, and have greater uplift, or force in warm rising air to form thunderstorms. In addition to cloud tops cooling, the strong convection has increased. During the morning hours on Oct. 6, infrared imagery indicated that deeper convection had developed in the northwestern quadrant of the storm, closer to the center.

At 2 p.m. EDT on Oct. 6, TD17's maximum sustained winds were still near 35 mph, although strengthening is forecast and it could become a tropical storm later today or tomorrow. TD17 was about 225 miles east-northeast of Grand Turk Island or 670 miles south-southwest of Bermuda.

The National Hurricane Center expects subtropical Depression 17 to become a tropical depression by the very early morning hours on Oct. 7.

Text credit: Rob Gutro and Hal Pierce
NASA's Goddard Space Flight Center/SSAI, Greenbelt, Md.






GOES-13 On Top of New Seventeenth Atlantic (Sub) Tropical Depression

GOES-13 shows a tight circulation and a long › View larger image
GOES-13 visible image of Subtropical Depression 17 (top, center) at 1145 UTC (7:45 a.m. EDT) shows a tight circulation and a long "tail" of clouds and showers that extend to the southeast of the center, reaching the northern Leeward Islands and Puerto Rico.
Credit: NOAA/NASA GOES Project
The GOES-13 satellite keeps a vigilant eye on the Atlantic Ocean and eastern U.S. and this morning at 5 a.m. EDT it saw System 97L organize into the seventeenth tropical depression of the Atlantic Ocean season. The only catch is that it is actually a subtropical depression, so it is currently known as Subtropical Depression 17 (TD17).

A subtropical storm is one where central convection (rapidly rising air that forms thunderstorms) is fairly near the center and it has a warming core in the mid-levels of the troposphere. Subtropical cyclones differ from tropical cyclones because they have broad wind patterns and their maximum sustained winds are located farther from the center of the system than tropical cyclones. In addition, they usually have colder temperatures in upper levels of the atmosphere than tropical cyclones (which have very warm cores). Finally, sea surface temperatures required for the formation of sub-tropical storms are about 5 degrees Fahrenheit cooler than needed for a tropical cyclone to develop (80 F).

TD17 is forecast by the National Hurricane Center to move into a more favorable environment to develop, and its core may warm up making it into a tropical depression or tropical storm, if it intensifies.

The Geostationary Operational Environmental Satellite called GOES-13 captured an infrared image of TD17 on October 6 at 1231 UTC (8:31 a.m. EDT). GOES satellites are managed by NOAA. NASA's GOES Project at NASA's Goddard Space Flight Center in Greenbelt, Md. creates images and animations from the satellite data and created today's image that shows TD17 has a tight circulation and a long "tail" of clouds and showers that extend to the southeast of the center, reaching the northern Leeward Islands and Puerto Rico.

At 5 a.m. EDT on Oct. 6, TD17's maximum sustained winds were 35 mph. It was located about 270 miles north-northwest of San Juan, Puerto Rico and 710 miles south of Bermuda near 22.2 North and 67.0 West. It was moving northwest at 8 mph with minimum central pressure of 1001 millibars. TD17's "tail" extends to the southeast from the center of the system, and may bring some heavy rainfall in the northern Leeward Islands and Puerto Rico over the next day as it moves northwest then turns northeast to head out to the open waters of the Atlantic.

Text credit: Rob Gutro
NASA's Goddard Space Flight Center, Greenbelt, Md.



October 5, 2010

GOES-13 Sees Another Potential Tropical Depression in Caribbean Sea

GOES-13 captured System 97L in the eastern Caribbean Sea and another low behind it in the central Atlantic Ocean › View larger image
The GOES-13 satellite captured a visible image of System 97L (center) in the eastern Caribbean Sea and another low (right) behind it in the central Atlantic Ocean on Oct. 5 at 1445 UTC (10:45 a.m. EDT).
Credit: NOAA/NASA GOES Project
The GOES-13 satellite passed over a low pressure area designated as "System 97L" earlier today and captured a visible image of the low in the eastern Caribbean Sea. System 97L appears in a good place for development into a tropical depression in the next day or two.

The National Hurricane Center currently gives the low pressure area known as System 97L an "80 percent chance of developing into a tropical depression in the next 48 hours." The low pressure area is located just north of the Virgin Islands near 19.0 North latitude and 65.3 West longitude. The visible image from the Geostationary Operational Environmental Satellite, GOES-13 showed a tight center of circulation with clouds, showers and thunderstorms extending mostly north, east and south of the center.

The visible image also shows another area of low pressure in the central Atlantic Ocean, trailing to the east of System 97L. Forecasters are giving this low a "near zero percent" chance of developing in the next 48 hours. That low is 950 miles east of the Lesser Antilles and is a large area of disorganized showers and thunderstorms.

System 97L however, has a much greater chance because upper level winds are waning and are forecast to continue weakening. That will enable System 97L to develop further. System 97L is moving northwestward near 5 to 10 mph, and is expected to be another big rainmaker in the region. Locally heavy rainfall from System 97L is possible over the next couple of days in the Leeward Islands, the Virgin Islands, Puerto Rico and Hispaniola.

GOES-13 is operated by the National Oceanic and Atmospheric Administration, and images are created by NASA's GOES Project, located at NASA's Goddard Space Flight Center, in Greenbelt, Md.

Text credit: Rob Gutro
NASA's Goddard Space Flight Center, Greenbelt, Md.