Tropical Storm Lisa

Lisa on Sept. 25 at 1523 UTC (11:23 a.m. EDT) the AIRS instrument showed much warmer cloud tops then than were seen in previous days, indicating that the cloud tops were not as high and cold as they were before. The stronger the thunderstorms and convection (rapidly rising air that forms thunderstorms that power a tropical cyclone) the stronger the storm.

Therefore, warmer cloud tops indicate that the power in a tropical cyclone is weakening as the clouds don't have the push to bring cloud tops higher. The last advisory on Lisa was issued by the National Hurricane Center on Sept. 25 at 5 p.m. EDT when Lisa's remnants were near 26.1 North and 29.4 west. At that time, Lisa's remnant low pressure area had maximum sustained winds near 30 mph, and weakening. Lisa was drifting north-northwest and continued in that direction over the weekend. Lisa has no chance for regeneration.

Now a Hurricane in the Gulf of Mexico

Karl on Sept. 15 and 16. On September 15 at 2153 UTC (5:53 p.m. EDT) Tropical storm Karl was still powerful and very well organized even though it had been over the Yucatan Peninsula for over nine hours. TRMM's Precipitation Radar showed that a cluster of very intense thunderstorms were dropping extreme amounts of rain near the storms center and along a feeder band in the western part of the storm.

Karl moved into the southern Gulf of Mexico between 0330 and 0430 UTC (near midnight Eastern Daylight Time). At 0603 UTC (2:03 a.m. EDT) as Karl was already in the Gulf, TRMM saw light to moderate rainfall occurring in the storm, falling at a rate between .78 to 1.57 inches per hour. Once Karl moved farther into the Gulf, the rainfall rates increased as Karl became a hurricane.

System 92L Looking More Like a Tropical Depression

As the Geostationary Operational Environmental Satellite called GOES-13 satellite keeps relaying data to NOAA (who manages the satellite) and the NASA GOES Project at NASA's Goddard Space Flight Center in Greenbelt, Md., the images created by the NASA GOES Project reveal that System 92L appears to be taking on the appearance of a tropical depression. In the imagery captured today, Sept. 14 at 1340 UTC (9:40 a.m. EDT), System 92L is developing the signature comma shape of a tropical cyclone, with outer bands developing around the center.

NOAA's National Hurricane Center in Miami, Fla. noted that the showers and thunderstorms within System 92L have even become a little better organized this morning. System 92L is forecast to continue marching west to northwest at 10 to 15 mph over the next couple of days. As it moves through the warm waters of the Caribbean Sea over the next two days, it has a 40% chance of becoming a tropical depression. That would make it the 13th tropical depression of the Atlantic Ocean Hurricane Season if that happens.

Category 4 Hurricane With Icy Cloud Tops and Heavy Rainfall

Last week, Igor was a tropical storm who faded into a tropical depression. The National Hurricane Center had forecast that over the weekend Igor would approach more favorable conditions (low wind shear and warm sea surface temperatures) causing it to strengthen into a hurricane and it did. Tropical storm Igor was upgraded by the National Hurricane Center (NHC) in Miami, Florida to a hurricane on Sunday, September 12 at 0300 UTC (Sept. 11 at 11 p.m. EDT) .

The Tropical Rainfall Measuring Mission (TRMM) satellite, which is operated jointly by NASA and the Japanese Space Agency, JAXA captured a good look at Igor a few hours after it reached hurricane status. TRMM passed over Igor and captured his rainfall rates at 0504UTC ( 1:04 a.m. EDT). The TRMM Precipitation Radar (PR) and TRMM Microwave Imager (TMI) instruments revealed that Igor had a well defined circular eye containing bands of heavy rainfall (falling at a rate of as much as 2 inches per hour).

Tropical Storm Igor

Tropical Storm Igor on September 8 at 2026 UTC ( 4:26 PM EDT). A rainfall analysis from TRMM's Precipitation Radar (PR) showed an area of strong thunderstorms producing heavy rainfall in the newly named storm.

At 2 p.m. EDT on Sept. 9, Igor's winds were still sustained near 40 mph, and unchanged from earlier today. Igor is moving somewhat erratically, however. Early this morning he was moving north, now northwest at 10 mph. Igor was centered about 65 miles northwest of Brava in the Cape Verde Islands, near 15.5 North and 25.4 West. Minimum central pressure is 1006 millibars.

Hurricane Earl

Hurricane Earl's movement north were captured from the Moderate Resolution Imaging Spectroradiometer (MODIS) that flies aboard NASA's Terra and Aqua satellites. MODIS on Terra captured an image of Earl on Sept. 3 at 12:04 p.m. EDT when it was located east of the Virginia coast. MODIS on NASA's Aqua satellite captured an image of Earl as it was parallel to the Maryland coast at 1:50 p.m. EDT. On Saturday, Sept. 4 at 1:15 p.m. EDT, MODIS on the NASA Terra satellite captured Earl when it was a tropical storm over Nova Scotia, Canada

Tropical Storm Hermine

Tropical Storm Hermine formed very quickly yesterday in the very warm waters of the Gulf of Mexico, and northeastern Mexico and southeastern Texas are now bearing the brunt of the storm. Infrared imagery taken from NASA's AIRS instrument showed a quick organization of strong thunderstorms around Hermine's center of circulation and very warm Gulf waters that powered her up.

At 11 p.m. EDT on September 6, Hermine made landfall as a strong tropical storm producing heavy rains over northeastern Mexico and South Texas.

This morning there's a tropical storm warning in effect from Bahia Algodones, Mexico Northward to Port O'Connor, Texas as Hermine is continuing to move inland in a north-northwest direction at 17 mph. At 8 a.m. EDT, Hermine's maximum sustained winds had decreased from their peak of 60 mph to 45 mph now that she's over land in south Texas. She's centered near 27.7 North and 98.2 West, which is about 35 miles southwest of Mathis, Texas. Mathis is about 171 miles north of Brownsville, Texas, the southernmost city in the state. Minimum central pressure is 991 millibars.

New Atlantic Depression 9

The Atlantic Ocean is in overdrive this week, and NASA satellite imagery captured the birth of the ninth tropical depression in the central Atlantic Ocean today, trailing to the east of Tropical Storm Fiona.

NASA's Atmospheric Infrared Sounder (AIRS) instrument, flying onboard the Aqua satellite, captured an infrared image of Tropical Depression 9 on Sept. 1 at 03:41 UTC (Aug. 31 at 11:41 p.m. EDT). It showed high thunderstorm cloud tops west and southwest of the center of circulation indicating strong convection.

At 1500 UTC (10 a.m. EDT) on Sept. 1, Tropical Depression 9 (TD9) was born in the Atlantic Ocean. It had maximum sustained winds near 35 mph, and was moving west at 15 mph. It was located about 830 miles west-southwest of the Cape Verde Islands, near 12.4 North and 35.8 West. Although there are warm sea surface temperatures (as seen in NASA's infrared AIRS imagery) over the 80 degree Fahrenheit threshold that's needed to power up tropical cyclones, there is wind shear in the area, so intensification will be slow to occur. is in overdrive this week, and NASA satellite imagery captured the birth of the ninth tropical depression in the central Atlantic Ocean today, trailing to the east of Tropical Storm Fiona.

NASA's Atmospheric Infrared Sounder (AIRS) instrument, flying onboard the Aqua satellite, captured an infrared image of Tropical Depression 9 on Sept. 1 at 03:41 UTC (Aug. 31 at 11:41 p.m. EDT). It showed high thunderstorm cloud tops west and southwest of the center of circulation indicating strong convection.

At 1500 UTC (10 a.m. EDT) on Sept. 1, Tropical Depression 9 (TD9) was born in the Atlantic Ocean. It had maximum sustained winds near 35 mph, and was moving west at 15 mph. It was located about 830 miles west-southwest of the Cape Verde Islands, near 12.4 North and 35.8 West. Although there are warm sea surface temperatures (as seen in NASA's infrared AIRS imagery) over the 80 degree Fahrenheit threshold that's needed to power up tropical cyclones, there is wind shear in the area, so intensification will be slow to occur.