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Hurricane Season 2010: Tropical Storm Bonnie (North Atlantic Ocean)
07.25.10
 
July 25, 2010

The GOES-13 satellite captured the remnants of Bonnie situated over Louisiana and western Mississippi on July 25. > View larger image
The GOES-13 satellite captured a visible image of the rounded area of clouds associated with the remnants of Bonnie, situated over Louisiana and western Mississippi on Sunday, July 25 at 7:40 a.m. EDT.
Credit: NASA/GOES Project
Remnant Low of Bonnie Over Louisiana and Western Mississippi as Seen by GOES-13 Satellite

The GOES-13 satellite captured a visible image of the clouds associated with the remnants of former tropical depression Bonnie, now over Louisiana and western Mississippi. Bonnie's remnants are producing scattered showers and thunderstorms today and tonight in those areas.

The GOES series of satellites are operated by the National Oceanic and Atmospheric Administration, and NASA's GOES Project, located at NASA's Goddard Space Flight Center, Greenbelt, Md. creates some of the GOES satellite images.

At 8:30 a.m. EDT (7:30 a.m. CDT) Bonnie's remnants generated an area of showers and thunderstorms north of Lake Pontchartrain in eastern Louisiana and western Mississippi. One of the thunderstorms spawned a tornado warning for Wathall and Washington Counties in western Mississippi at that time.

Bonnie's center is located inland south of New Orleans, Louisiana, and the bulk of the showers and thunderstorms associated with it are mainly to the west and north of the remnant low's center. To see the movement of Bonnie's remnants, go to the live stream from the NASA GOES web page: http://goes.gsfc.nasa.gov/goescolor/goeseast/hurricane2/movie/latest_sml.mov. (Note: this will only show Bonnie as long as she is in existence as it is updated continually).

The National Weather Service in New Orleans has issued a Coastal Flood Advisory in effect until 7 p.m. CDT this evening. The remnant low pressure formerly known as tropical depression Bonnie is moving inland across Louisiana today. Moderate to strong south to southeast winds near the coast will diminish today. Tides however will remain as much as two feet above normal over Hancock County Mississippi and the east facing coastal areas of southeast Louisiana.

Winds out of the southeast in the area of Bonnie are not because of the remnant low, but because of the high pressure area over the Gulf. Winds are expected to be light today, between 5 and 10 mph shifting to the south.

The National Weather Service forecast for New Orleans today, Sunday, July 25 includes showers and thunderstorms today and tonight with hot and humid conditions. The high is expected near 92, but the humidity will bring the heat index to 105 Fahrenheit today. National Weather Service live radar: http://radar.weather.gov/radar.php?rid=LIX&product=NCR&overlay=11101111&loop=yes.

The National Hurricane Center noted that "Regeneration is not expected as the system moves northwestward at about 10 mph. There is a low chance...near 0 percent...of this system becoming a tropical cyclone during the next 48 hours."

Text credit: Rob Gutro, NASA/Goddard Space Flight Center



July 24, 2010

This image from the GOES-13 clearly shows Bonnie's center (the small circular area southeast of Louisiana). > View larger image
This image from the GOES-13 satellite on July 24 at 1140 UTC (7:40 a.m. EDT) clearly shows Bonnie's center (the small circular area southeast of Louisiana is separated from the bulk of its clouds and showers to the northeast.
Credit: NASA/GOES Project
NASA's Aqua satellite provided a very clear image of Tropical Storm Bonnie as it was moving into the Gulf of Mexico. > View larger image
NASA's Aqua satellite provided a very clear image of Tropical Storm Bonnie over Florida on July 23 at 18:50 UTC (4:50 p.m. EDT) as it was moving into the Gulf of Mexico.
Credit: NASA/MODIS Rapid Response Team
This TRMM satellite 3-D image shows heavy rain associated with a tall convective tower near the center of the storm. > View larger image
This TRMM satellite 3-D image shows heavy rain associated with a tall convective tower (shown in red) that extends to over 15 km (over 9 miles high) near the center of the storm.
Credit: NASA/SSAI, Hal Pierce
Bonnie Struggling in the Gulf of Mexico due to Wind Shear

A strong southeasterly wind shear is preventing Tropical Depression Bonnie from strengthening over the Gulf of Mexico, where the storm sits on Saturday, July 24. GOES-13 satellite image today provides a good picture of the effects of that shear as the center of Bonnie visibly seems to be southwest of the bulk of its clouds and showers.

The Geostationary Operational Environmental Satellite, GOES-13 that watches weather over the eastern U.S. captured a visible image of Tropical Depression Bonnie this morning, July 24, at 1140 UTC (7:40 a.m. EDT). The image clearly shows Bonnie's center as a small circular area southeast of Louisiana located to the southeast of the bulk of Bonnie's clouds and showers to the northeast.

The National Hurricane Center noted that "the southeasterly shear is not expected to abate prior to bonnie reaching the coast and none of the intensity guidance shows intensification. However...the official forecast will keep the possibility of re-strengthening to a tropical storm before bonnie makes landfall. An alternate scenario that remains possible is for bonnie to degenerate to an open trough today. That scenario is supported by some of the global models."

At 8 a.m. EDT, Bonnie's maximum sustained winds were holding near 30 mph. Bonnie's center was located near latitude 27.6 north and longitude 86.1 west. That's about 215 miles east-southeast of the mouth of the Mississippi River and 160 miles south-southwest of Apalachicola, Florida. The depression is moving toward the west-northwest near 20 mph and a gradual decrease in forward speed is expected today with little change in the direction of motion. On this track the center of Bonnie is forecast to approach the northern Gulf coast tonight.

A tropical storm warning is still in effect for Destin, Florida to Morgan City, Louisiana including Lake Pontchartrain. However, the National Hurricane Center noted that the tropical storm warning will likely be discontinued later this morning (July 24).

Tropical Depression Bonnie is expected to produce total rainfall accumulations of 1 to 2 inches over portions of southern Louisiana, southern Alabama, southern Mississippi and the far western Florida panhandle...with possible isolated maximum amounts of 3 inches. Gusty winds will also be experienced in those areas today and storm surge is expected between 1 and 3 feet.

Before coming into the Gulf of Mexico, Tropical Storm Bonnie made landfall in South Florida on Friday the 23rd of July 2010. The center of the storm came ashore near Cutler Bay along the southeast coast of Florida, about 40 miles south of Miami, around 11:00 a.m. local time (EDT) with sustained winds of 40 mph (~65 mph) according to the National Hurricane Center.

Bonnie formed a day earlier between the central Bahamas and eastern Cuba from a west-ward propagating tropical wave that had emerged off of the coast of Africa a little over a week ago. The storm has been moving steadily towards the west-northwest at a fairly rapid pace after forming south of the Bahamas.

The Tropical Rainfall Measuring Mission satellite (known as TRMM) captured unique images of Bonnie as it was approaching the southeast coast of Florida during the early morning hours on Friday, July 23. The images were taken at 07:53 UTC (3:53 am EDT) July 23 just after Bonnie had passed over Andros Island in the southwestern Bahamas. One TRMM image showed the horizontal pattern of rain intensity within the storm.

Rain rates in the center of the orbit "swath" or path are based on the TRMM Precipitation Radar (PR), and those in the outer swath on the TRMM Microwave Imager (TMI). The rain rates are overlaid on infrared (IR) data from the TRMM Visible Infrared Scanner (VIRS).

TRMM revealed that in general, Bonnie is a pretty small storm and contains very little in the way of rain. Patchy areas of mostly light to occasionally moderate rain are spread around but away from the center. There is, however, one area of intense rain located near the center. The storm is not very well organized with only weak banding (curvature) evident in the rainbands away from the center and no evidence of an eye.

A second image using TRMM data was created to show the storm in 3-D. That image showed the area of heavy rain evident in the rainfall image was associated with a tall convective tower that extends to over 15 km (over 9 miles high) near the center of the storm. Oftentimes, these tall towers can be a sign of strengthening as they indicate the presence of strong showers and thunderstorms that are releasing large amounts of heat into the storm. However, because it was only weakly organized and under the influence of moderate to strong southeasterly wind shear, Bonnie was unable to strengthen before making landfall in south Florida.

The National Hurricane Center forecast track as of 8 a.m. EDT on July 24 takes Bonnie into southeastern Louisiana near midnight tonight, making landfall in the bayou near Barataria Bay, south of New Orleans. For updates on Tropical Depression Bonnie's track and latest forecast, visit the National Hurricane Center website at: www.nhc.noaa.gov.

The GOES series of satellites are operated by the National Oceanic and Atmospheric Administration, and NASA's GOES Project, located at NASA's Goddard Space Flight Center, Greenbelt, Md. creates some of the GOES satellite images. TRMM is a joint mission between NASA and the Japanese space agency JAXA.

Text credit: Rob Gutro and Steve Lang, NASA/Goddard Space Flight Center



July 23, 2010

thermal infrared image of Tropical Storm Bonnie › View larger image
The temperatures of Tropical Storm Bonnie's cloud tops are shown in this July 23 thermal infrared image from the AIRS instrument on NASA's Aqua spacecraft. The coldest clouds and heaviest precipitation are shown in purples and blues.
Credit: NASA/JPL-Caltech
Bonnie Takes Aim at an Oily Gulf

Tropical Storm Bonnie, the second named storm of the 2010 Atlantic hurricane season, moved across the southern Florida peninsula on Friday afternoon, July 23, 2010, and is now taking aim at the Gulf of Mexico. The forecast track is expected to take it over or near the BP Deepwater Horizon oil spill on July 24.

According to NOAA's National Hurricane Center, Bonnie made landfall in South Florida with maximum sustained winds near 65 kilometers (40 miles) per hour. As it encountered land, it was downgraded to a tropical depression, with maximum sustained winds of 55 kilometers (35 miles) per hour. Bonnie is expected to regain tropical storm strength as it enters the open waters of the Gulf of Mexico Friday night and Saturday. At 5 p.m. EDT July 23, Bonnie was located about 55 kilometers south of Ft. Myers, Fla., moving to the west-northwest at 30 kilometers (18 miles) per hour. Bonnie is expected to slow and move over the eastern Gulf of Mexico Friday night, July 23, and Saturday, July 24, and reach the northern Gulf Coast late Saturday.

Bonnie is expected to produce total rainfall accumulations of 3 to 8 centimeters (1 to 3 inches) over parts of southeastern Louisiana, southern Alabama, southern Mississippi and the far western Florida panhandle, with possible isolated maximum amounts of up to 13 centimeters (5 inches). Additional rainfall amounts of 3 to 5 centimeters (1 to 2 inches) are possible today over Central and South Florida.

Of particular concern to Gulf Coast residents and oil spill response personnel is Bonnie's storm surge, which could potentially carry oil from the spill inland. The storm surge is expected to raise water levels by as much as 1 to 1.5 meters (3 to 5 feet) above ground level along the immediate coast near and to the right of where the center of Bonnie makes landfall on the northern Gulf Coast.

The NASA Jet Propulsion Laboratory-built and managed Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite captured this infrared image of Bonnie when it was a tropical storm at 2:47 p.m. EDT (18:47 UTC) on July 23, 2010. The AIRS data create an accurate 3-D map of atmospheric temperature, water vapor and clouds, data that are useful to hurricane forecasters. The image shows the temperature of Bonnie's cloud tops or the surface of Earth in cloud-free regions. The coldest cloud-top temperatures appear in purple, indicating towering cold clouds and heavy precipitation. The infrared signal of AIRS does not penetrate through clouds. Where there are no clouds, AIRS reads the infrared signal from the surface of the ocean waters, revealing warmer temperatures in orange and red.

For more information on AIRS, visit: http://airs.jpl.nasa.gov/ . For more information on NASA's research of hurricanes/tropical cyclones, visit: http://www.nasa.gov/mission_pages/hurricanes/main/index.html .

Text credit: Alan Buis, NASA/Jet Propulsion Laboratory



The bulk of Bonnie's clouds are over south Florida, although her center is southeast of there. > View larger image
GOES-13 captured a visible image of Tropical Storm Bonnie as she tracks across Florida today, July 23. At 1625 UTC (12:25 p.m. EDT), GOES-13 visible imagery showed the bulk of Bonnie's clouds over south Florida, although her center is southeast of there.
Credit: NASA/GOES Project
Tropical Storm Bonnie Disorganized Over South Florida

Tropical Storm Bonnie was crossing over south Florida at 11 a.m. EDT today, July 23, and it is being battered by strong wind shear. Satellite and radar data have indicated that the center of Bonnie's circulation is southeast of the strongest convection and showers, which are currently located over southeastern Florida.

The Geostationary Operational Environmental Satellite, GOES-13 continues to keep an eye on Bonnie as she tracks across Florida today. At 1625 UTC (12:25 p.m. EDT), GOES-13 visible imagery showed the bulk of Bonnie's clouds over south Florida, although her center is southeast of there. GOES is operated by the National Oceanic and Atmospheric Administration, and NASA's GOES Project, located at NASA's Goddard Space Flight Center, Greenbelt, Md. creates some of the GOES satellite images.

At 11 a.m. EDT, Bonnie's center was near 25.4 North and 80.3 West, about 30 miles south-southwest of Miami, Fla. and 130 miles southeast of Fort Myers, Fla. Bonnie's maximum sustained winds remain near 40 mph, and she's moving west-northwest near 18 mph. Bonnie is expected to produce total rain accumulations of 1 to 3 inches over south Florida with possible isolated maximum amounts of 5 inches.

The National Hurricane Center forecast indicates Bonnie will move across Florida today and enter the eastern Gulf of Mexico tonight. She is forecast to approach the northern Gulf coast late on Saturday. Warnings are posted for the following: in the Bahamas, a tropical storm warning is in force for the northwestern Bahamas. In Florida a tropical storm warning is in effect from Deerfield Beach to the entire Florida Keys, including Florida Bay and north along the west coast to Englewood. Tropical Storm Warnings are also posted for the northern Gulf coast from Destin, Fla. to Morgan City, La. including Lake Pontchartrain. A Tropical storm watch is up from Deerfield Beach, Fla. north to Jupiter Inlet, including Lake Okeechobee, Fla. Storm surge expected is for up to 1 or 2 feet above normal tidal levels in the Bahamas and Florida, and tornadoes are possible over extreme southern Florida as Bonnie makes her way across the state.

To see updated movies from GOES-13 of Bonnie's track into the Gulf of Mexico, go to: www.nhc.noaa.gov.

Residents along the northern Gulf of Mexico coastline should be preparing for Bonnie's arrival this weekend.

Text credit: Rob Gutro, NASA/Goddard Space Flight Center



This visible image from the GOES-13 satellite on July 23 shows Tropical Storm Bonnie's cloud-covered center south of Miami, Fla. > View larger image
This visible image from the GOES-13 satellite on July 23 at 1140 UTC (7:40 am. EDT) shows Tropical Storm Bonnie's cloud-covered center south of Miami, Fla.
Credit: NASA/GOES Project
GOES-13 Sees New Tropical Storm Bonnie Raining on South Florida

Tropical Depression 3 strengthened into tropical storm Bonnie at 6:15pm EDT on July 22, when it was centered about 200 miles southeast of Nassau, Bahamas. At 5 a.m. EDT today, July 23, Bonnie was 155 miles southeast of Miami and the GOES-13 satellite has been providing forecasters a visible image of Bonnie continually.

The visible image on July 23 at 1140 UTC (7:40 a.m.) EDT) from the Geostationary Operational Environmental Satellite called GOES-13 satellite showed Tropical Storm Bonnie's cloud-covered center south of Miami, Fla. GOES satellites are operated by NOAA. The NASA GOES Project, located in Greenbelt, Md. creates imagery and animations of GOES imagery.

A tropical storm watch is in effect for the east coast of Florida north of Deerfield Beach to Jupiter Inlet including Lake Okeechobee, and the Northern Gulf Coast from Destin, Florida to Morgan City, Louisiana. Tropical storm warnings are in effect for the Northwestern Bahamas, the Florida east coast from Deerfield Beach southward, including all of the Florida Keys, Florida Bay and along the Florida west coast northward to Englewood.

At 5 a.m. EDT, Bonnie's center was located near latitude 24.1 north and longitude 78.6 west, which is about 155 miles southeast of Miami, Fla. and about 165 miles east-southeast of Marathon, Florida. Maximum sustained winds were near 40 mph. Bonnie is moving toward the west- northwest near 18 mph and the National Hurricane Center expects it to continue moving in this direction over the next day or two. Bonnie is expected to pass near the Florida Keys and southern Florida then move over the eastern Gulf of Mexico tonight. Tropical storm watches issued for southern Mississippi and southeast Louisiana as Bonnie is forecast to move that way this weekend.

Miami is under a tropical storm warning today. This morning at 8:05 a.m. EDT, a large area of moderate to heavy rainfall was moving over Miami north to West Palm Beach. A flood watch is in effect through the afternoon of July 23 for all of South Florida. For live radar from the National Weather Service, visit: http://radar.weather.gov/radar.php?rid=AMX&product=NCR&overlay=11101111&loop=yes.

The National Hurricane Center noted that tropical storm conditions will continue of parts of the northwestern Bahamas this morning and then spread over southern Florida, including the Keys. Bonnie is expected to produce total rain accumulations of 1 to 3 inches over south Florida with possible isolated maximum amounts of 5 inches. Additional rainfall amounts of 1 to 2 inches are possible over the northwestern Bahamas. Isolated tornadoes are possible over extreme southern Florida later today. For the latest updates on Bonnie, visit: www.nhc.noaa.gov.

GOES-13 will continue to provide coverage in visible images during the daytime and infrared images over night-time hours and will watch Bonnie as she moves into the Gulf of Mexico this weekend.

For a video of GOES-13 satellite imagery that shows the formation of Tropical Depression 3 strengthening into Tropical Storm Bonnie from July 21 at 1245 UTC (8:45 a.m. EDT) through July 23 at 1245 UTC (8:45 a.m. EDT), go to: http://www.youtube.com/watch?v=cZXOzr93OaI.

Text credit: Rob Gutro, NASA/Goddard Space Flight Center



July 22, 2010

GOES-13 captured Tropical Depression 3 (right) as it was bringing rains over the Bahamas and Hispaniola. > View larger image
GOES-13 captured a visible image on July 22 at 1515 UTC (11:15 a.m. EDT) of Tropical Depression 3 (right) as it was bringing rains over the Bahamas and Hispaniola.
Photo Credit: NASA/GOES Project
> View GOES Video:   From July 19 at 2132 UTC (5:32 p.m. EDT) through July 22 at 1515 UTC (11:15 a.m. EDT) showing the development of System 97L over the Virgin Islands and Puerto Rico, moving into the southern Bahamas.
Video Credit: NASA/GOES Project
The purple area of TD 3 located over the southern Bahamas shows strong convection, and indicates heavy rainfall > View larger image
This infrared image of the western half of Tropical Depression 3 from NASA's Aqua satellite was captured on July 22 at 3:05 a.m. EDT. The purple area located over the southern Bahamas shows strong convection, and indicates heavy rainfall. The eastern half of the storm was out of the satellite's view.
Credit: NASA/JPL, Ed Olsen
GOES-13 Sees Tropical Depression 3 Form in the Atlantic: Bahamas, Florida Under Warnings

The GOES-13 satellite has kept an eye on System 97L all week, and it has now developed into a tropical depression. NASA's GOES Project has created a movie showing its development over the last three days, and will continue to monitor it.

Forecasters at the National Hurricane Center have been monitoring System 97L for days now with NOAA and NASA satellite data, ship and buoy observations. At 11 a.m. EDT this morning, July 22, System 97L strengthened and organized into the third tropical depression of the Atlantic Ocean hurricane season triggering warnings for the Bahamas and Florida.

The Geostationary Operational Environmental Satellite known as GOES-13, continually takes images over the eastern U.S. and the latest imagery shows Tropical Depression Three (TD3) getting organized over the Bahamas. NASA's GOES Project, located at NASA's Goddard Space Flight Center in Greenbelt, Md. created a movie of System 97L from July 19 at 2132 UTC (5:32 p.m. EDT) through July 22 at 1515 UTC (11:15 a.m. EDT) showing its development over the Virgin Islands and Puerto Rico, moving into the Bahamas.

The government of the Bahamas has issued a tropical storm warning for the central and northwestern Bahamas. In addition, a tropical storm warning has been issued for the Florida east coast from Golden Beach southward including the entire Florida Keys and Florida Bay and along the west coast of Florida northward to Bonita Beach. A tropical storm watch has been issued for the east coast of Florida from north of Golden Beach to Jupiter inlet including Lake Okeechobee.

At 1100 a.m. EDT the center of newly formed tropical depression three (TD3) was located near latitude 21.9 north and longitude 75.0 west. Maximum sustained winds are near 35 mph with higher gusts. TD3 is moving toward the west-northwest near 15 mph and it is expected to continue in this direction with an increase in forward speed during the next 48 hours. Estimated minimum central pressure is 1008 millibars. The depression could become a tropical storm later today.

The Bahamas and Florida will be affected by winds, heavy rainfall and storm surge. The National Hurricane Center reports that winds near tropical storm force are already affecting portions of the southeastern Bahamas. "Tropical storm conditions will gradually spread over the central and northwestern Bahamas tonight and Friday," the NHC said. "Weather conditions will begin to deteriorate on the Florida coast and Florida Keys within the warning area on Friday."

Rainfall between 2 and 4 inches are expected over south Florida, while the northwest Bahamas may experience 5 to 7 inches. Storm surges of 1 to 2 feet above ground may be experienced over parts of the Bahamas and Florida Keys.

Text credit: Rob Gutro, NASA/Goddard Space Flight Center



July 21, 2010

High (strong) thunderstorms in System 97L were over Haiti, the Dominican Republic, Puerto Rico, and the Virgin Islands. > View larger image
NASA's infrared AIRS image showed high (strong) thunderstorms in System 97L were over Haiti, the Dominican Republic, Puerto Rico, and the Virgin Islands. The bulk of the thunderstorm activity was east of Puerto Rico. Strong convective activities as indicated by high thunderstorms (in purple) are cold as -63F.
Credit: NASA/JPL, Ed Olsen
TRMM captured the image of System 97L's rainfall on July 20 at 9:36 p.m. EDT. > View larger image
TRMM captured the image of System 97L's rainfall on July 20 at 9:36 p.m. EDT. The red areas indicate heavy rainfall of over 50 millimeters (~2 inches) per hour. The yellow and green areas indicate moderate rainfall between .78 to 1.57 inches per hour.
Credit: NASA/SSAI, Hal Pierce
NASA Satellites See System 97L Serve Up a Soaking

System 97L may not yet be a tropical depression, but it feels like it to the residents of Puerto Rico, the Virgin Islands and Hispaniola. NASA satellite data captured both rainfall and cloud temperatures as this system continues to organize.

The National Hurricane Center in Miami, Fla. predicted that conditions were favorable for formation of a tropical depression or tropical storm from System 97L - an area of disturbed weather over Puerto Rico and Hispaniola.

The Tropical Rainfall Measuring Mission (TRMM) satellite passed over that area on July 21 at 0136 UTC (July 20 at 9:36 p.m. EDT) and captured data used in a rainfall analysis. This rainfall analysis shows that intense rainfall was already affecting southwestern Haiti. Some areas are receiving up to 2 inches of rain per hour as System 97L continues to develop.

Rain rates are created from different instruments aboard TRMM. The rain rates in the center of TRMM images are derived from the TRMM Precipitation Radar, the only space borne radar of its kind, while those in the outer portion are from the TRMM Microwave Imager. The rain rates are then overlaid on infrared data from the TRMM Visible Infrared Scanner to create an entire image. Today's image included infrared data from the Geostationary Operational Environmental Satellite (GOES-13) to fill in locations not viewed by the TRMM satellite. The TRMM rainfall images and GOES images are created at NASA's Goddard Space Flight Center, in Greenbelt, Md.

On July 21 at 6:23 UTC (2:23 a.m. EDT) NASA's Aqua satellite flew over System 97L and using the technology from the Atmospheric Infrared Sounder (AIRS) instrument, captured a view of System 97L's cold cloud top temperatures and warm ocean surface waters below it.

The AIRS image showed some high thunderstorms (indicating strong storms) that make up System 97L were over Haiti, the Dominican Republic, Puerto Rico, and the Virgin Islands. The bulk of the thunderstorm activity was east of Puerto Rico and over the Virgin Islands at the time the Aqua satellite flew overhead. Thunderstorm cloud tops were colder than -63 Fahrenheit, while ocean surface temperatures were warmer than the 80 degrees Fahrenheit needed to power a tropical cyclone.

By 8 a.m. EDT on July 21, satellite data indicated that the shower activity associated with System 97L was becoming less organized. The National Hurricane Center (NHC) noted that a tropical depression is not expected to form today, but conditions are still favorable for that development.

System 97L is moving west-northwest near 10 mph, and will affect the Bahamas tomorrow, Thursday, July 22. The NHC still maintains a 60 percent chance that System 97L will develop into a tropical depression in the next 48 hours.

Meanwhile, locally heavy rains and gusty winds will continue to affect the Virgin Islands, Puerto Rico and Hispaniola today. The NHC said that the gusty winds and heavy rains "will likely spread over the Turks and Caicos Islands and the Bahamas during the next couple of days. The heavy rains could cause life-threatening flash floods and mud slides in mountainous areas."

Text credit: Rob Gutro, NASA/Goddard Space Flight Center



July 20, 2010

AIRS detected strong convection with high thunderstorm cloud tops as cold as -63 Fahrenheit. > View larger image
On July 20 at 18:11 UTC (2:11 p.m. EDT) NASA's AIRS instrument on the Aqua satellite detected strong convection (purple) east of the center of System 97L, with high thunderstorm cloud tops as cold as -63 Fahrenheit.
Credit: NASA/JPL, Ed Olsen
System 97L's Chances Just Improved, Tropically Speaking

The National Hurricane Center noted in its afternoon update today, July 21 that the showers and thunderstorms associated with System 97L that has been soaking Puerto Rico and the Virgin Islands appears to be coming together better for tropical cyclone development.

Showers and thunderstorms associated with System 97L, a vigorous tropical wave currently extend from the northern Leeward Islands westward to Hispaniola.

On July 20 at 18:11 UTC (2:11 p.m. EDT) NASA's Atmospheric Infrared Sounder (AIRS) instrument (that flies on the Aqua satellite) detected strong convection east of the center of System 97L, with high thunderstorm cloud tops as cold as -63 Fahrenheit. The National Hurricane Center noted "Although the system does not yet have a closed circulation satellite imagery suggests that a surface low pressure area is becoming better defined just north of the eastern tip of Hispaniola."

Because environmental conditions are expected to be favorable for development, the National Hurricane Center has noted that System 97L now has a high chance (60%) for development into a tropical depression.

Text credit: Rob Gutro, NASA/Goddard Space Flight Center



GOES-13 showed clouds over the Northern Leeward Islands, the Virgin Islands, Puerto Rico, and Dominican Republic > View larger image
A visible image from the GOES-13 satellite at 11:15 a.m. EDT on July 20 showed clouds over the Northern Leeward Islands, the Virgin Islands, Puerto Rico, and Dominican Republic.
Credit: NASA/GOES Project
GOES-13 Keeping an Eye on System 97L for Development

Forecasters are watching an active tropical wave near Puerto Rico that is producing showers and thunderstorms in a large area. The GOES-13 Satellite captured a visible image of System 97L showing a large area of cloudiness and thunderstorms while local radar showed heavy rainfall in the eastern part of Puerto Rico mid-day on July 20.

A visible image from the Geostationary Operational Environmental Satellite called GOES-13 taken at 1515 UTC (11:15 a.m. EDT) on July 20 showed clouds (and showers and thunderstorms) over the Northern Leeward Islands, the Virgin Islands, Puerto Rico, and Dominican Republic. 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, Greenbelt, Md.

The National Hurricane Center noted that showers and thunderstorms have become more concentrated near Puerto Rico and the Virgin Islands during the morning hours of July 20. A flash flood watch is now in effect for all of Puerto Rico, including Culebra and Vieques and for all of the U.S. Virgin Islands through this evening.

Although by mid-day showers and thunderstorms were only affecting the eastern half of Puerto Rico, they are forecast to spread across other sections of the local islands today and this evening, according to the National Weather Service (NWS). The NWS forecast noted that there could be periods of moderate to heavy rainfall which may result in flash flooding and river flooding as well as mudslides in areas of steep terrain. National Weather Service radar from Puerto Rico and the Virgin Islands on July 20 at 16:15 UTC (12:15 p.m. EDT) showed heavy rain over the eastern side of Puerto Rico and a special marine warning over the open ocean east of the island.

Even if System 97L doesn't develop it will still bring heavy rainfall and gusty winds to the Northern Leeward Islands, The Virgin Islands, Puerto Rico, the Dominican Republic, Haiti, Eastern Cuba, Turks and Caicos Islands, and the Southeastern Bahamas during the next couple of days. The National Hurricane Center gives System 97L a "40 percent chance" of developing into a tropical depression in the next 48 hours.

Text credit: Rob Gutro, NASA/Goddard Space Flight Center