System 95B-Northern Indian Ocean

The Atmospheric Infrared Sounder (AIRS) instrument that flies aboard NASA's Aqua satellite passed over System 95B from its orbit in space and captured an infrared image of the low pressure area on April 29 at 07:53 UTC. Infrared imagery acts like taking the temperature of the system's clouds - and there were some high, very cold clouds that indicated powerful convection and strong thunderstorms in the center. Some cloud top temperatures were as cold as or colder than -63F/-52C. Infrared imagery indicated that there was scattered convection around all sides of the low-level center, and even some curved banding of thunderstorms.

On April 29, System 95B was located about 420 nautical miles east-northeast of Colombo, Sri Lanka near 9.5 North and 96.5 East. System 95B is drifting and currently has estimated sustained surface winds between 15 and 20 knots. Despite the waters in the Bay of Bengal being warm enough to sustain the development of a tropical cyclone, there is a westerly wind field present.

System 91L-Atlantic Ocean

System 91L sparked the interest of forecasters because it had a small chance to develop into a subtropical or tropical storm last week. Now that chance is zero. On Saturday, April 23, 2011, the showers associated with System 91L diminished. At that time, the low was centered about 360 miles north of San Juan, Puerto Rico. Wind shear had taken its toll on the low and weakened it . As a result, the National Hurricane Center issued their final notice about the system on Saturday.

Currently there are no tropical cyclones expected elsewhere in the Atlantic Ocean, and the official hurricane season doesn't start until June 1.

NASA's TRMM Satellite Estimates Australia's Cyclone Season Rainfall

NASA's TRMM satellite measures rainfall from space and data from it was used to create a map of total cyclone rainfall. The TRMM satellite is managed by both NASA and the Japanese Space Agency, JAXA.

At NASA's Goddard Space Flight Center in Greenbelt, Md. data from the Tropical Rainfall Measuring Mission (TRMM) satellite was used to create the cyclone rain maps. TRMM-based, near-real time Multi-satellite Precipitation Analysis (TMPA), data were used in an analysis to show rainfall contributed by tropical cyclones that have affected Australia in 2011. Hal Pierce of the NASA TRMM team created the image and included the tracks of tropical cyclones on the image.

"The largest tropical cyclone rainfall contribution was over the coast of northwestern Australia with estimated totals of over 600 millimeters (~23.6 inches)," Pierce said. "Cyclones Bianca, Carlos, Twenty, Errol and their remnants were close enough to the northwestern coast of Australia to add to these rainfall totals."

Tropical Low #1 -Atlantic

Hurricane season doesn't start in the Northern Atlantic Ocean until June 1, but a low pressure system in doesn't seem to want to follow the calendar. There's a low pressure area with a small chance for development north-northeast of Puerto Rico, and the GOES-13 satellite captured a visible image of the storm.

The National Hurricane Center (NHC) issued a Special Tropical Weather Outlook today, April 20, that noted the low pressure area was located about 460 miles northeast of San Juan, Puerto Rico at 3:35 p.m. EDT. The NHC noted that slow development is possible over next couple of days. The low is moving west -northwest at 10mph.

The image was created using satellite imagery was captured on April 20 at 17:45 UTC (1:45 p.m. EDT) from the Geostationary Operational Environmental Satellite (GOES-13). Although it is not easy to pick out the center of circulation in the image, it is located to the west of the largest area of clouds.

Tropical Storm Errol

NASA's Aqua Satellite Sees Weaker Tropical Depression Errol Crossing West Timor

NASA's Aqua satellite captured an infrared image of Tropical Depression Errol's warming cloud temperatures as it was crossing the southern tip of West Timor today. West Timor is the western and Indonesian portion of the island of Timor. To the east lies the Timor Sea, to the west is the Southern Indian Ocean.

The Atmospheric Infrared Sounder (AIRS) instrument aboard NASA's Aqua satellite captured an infrared image on April 18 at 04:53 UTC (12:53 a.m. EDT) that showed very little strong convection (rapidly rising air that forms thunderstorms) remained in Errol. The strongest areas of convection had cloud-top temperatures as cold as -63F/-52C. However, AIRS data shows that much of the cloud top temperatures in the depression have since warmed. Cloud-top temperatures are important because they tell forecasters how high thunderstorms are, and the higher the thunderstorm, the colder the cloud tops and the more powerful the thunderstorms. Warming cloud top temperatures mean lower cloud heights and indicate that the storm is growing weaker. It means that there's not as much power to lift the air up to create the thunderstorms that power it.

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Tropical Storm Errol-Southern Indian Ocean

The low pressure area formerly known as System 92S has strengthened overnight and developed into Tropical Storm Errol today, April 15. Infrared imagery from NASA's Aqua satellite showed strong thunderstorms near Errol's center, but they remained off-shore from Western Australia's northern coast.

An infrared image on April 14 at 0517 UTC from NASA's Atmospheric Infrared Sounder (AIRS) instrument shows that Tropical Storm Errol's strongest thunderstorms with the coldest, highest cloud tops were off-shore from the northern coast of Western Australia. Those thunderstorms had cloud-top temperatures as cold as or colder than -63 F/-52C and brought heavy rainfall. Multispectral satellite imagery also showed a well-defined center of circulation in Errol, and bands of thunderstorms wrapping around its souther and western edges.

Tropical Storm Errol has sustained winds of 40 knots with higher gusts, and is kicking up rough surf along the northern coast of Western Australia today. Errol's center was about 270 miles (434 km) west of Darwin, Australia near 13.1 South latitude and 126.3 East longitude. Errol is currently drifting south-southwestward at 2 knots (2 mph/~4 km) but is expected to start moving to the west-northwest as a result of a strengthening ridge of high pressure building up over Western Australia.

System 92S-Southern Indian Ocean

Visible imagery from NASA's Aqua satellite showed strong convection around the center of developing tropical low 92S that lies north of the Western Australia coastline. System 92S is still in the Timor Sea today. Early this morning (EDT), April 14, it was about 315 miles west of Darwin, Australia. The southern extent of the low pressure area's clouds, however, already stretch over land in Western Australia. The center of System 92S' circulation at 06:30 UTC was near 13.0 South latitude and 125.5 East longitude. The system appears to be consolidating and there is strong convection near the center of circulation. By 8 p.m. WST Australia local time System 92S' center was near 12.5S and 126.3E. That is 127 miles north of Kalumburu. Although it moved from this morning, System 92S is now nearly stationary.

The Australian Bureau of Meteorology has issued a Strong Wind Warning from Kuri Bay to Wyndham for the next 24 to 36 hours. That warning area can expect east-southeasterly wind between 20 and 30 knots with higher gusts and squalls. Seas are expected to be 6 to 10 feet. The Moderate Resolution Imaging Spectroradiometer instrument that flies aboard NASA's Aqua satellite captured a visible image of System 92S on 0519 UTC on April 13. In the imagery there was area near the center that appears to have texture and shadows. That area is one of higher, more powerful thunderstorms, and is still over open waters of the Timor Sea.