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Hurricane Season 2012: Tropical Storm Heidi (Southern Indian Ocean)
01.12.12
 
Tropical Storm Heidi's Temperature, Cloud Heights and Rainfall Grabbed by NASA Satellites › Larger image
NASA's Aqua satellite passed over Heidi on January 12, 2012 at 06:00 UTC (1 a.m. EST) and captured a visible image of the storm. The image showed that Heidi maintained her well-rounded shape and even appeared to hint at an eye in the center after making landfall on the Pilbara Coast of Western Australia.
Credit: NASA Goddard MODIS Rapid Response Team


Tropical Storm Heidi's Temperature, Cloud Heights and Rainfall Grabbed by NASA Satellites › Larger image
IMAGE #2- NASA's TRMM Satellite passed over Tropical Cyclone Heidi on January 10 (left) and January 12, 2012 (center) and captured rainfall rates and cloud heights in the storm. The Jan. 12 3-D image (far right) showed some high, strong thunderstorms. Light to moderate rainfall, depicted in blue and green is falling at a rate between .78 to 1.57 inches (20 to 40 mm) per hour. Heavy rainfall, seen in red was occurring at a rate of 2 inches (50 mm) per hour.
Credit: SSAI/NASA, Hal Pierce


Tropical Storm Heidi's Temperature, Cloud Heights and Rainfall Grabbed by NASA Satellites › Larger image
Over the days of January 10, 11 and 12, 2012, infrared data from the AIRS instrument on NASA's Aqua satellite showed cloud top temperatures growing increasingly colder (purple is the coldest, greater than -63F) as Tropical Storm Heidi strengthened and cloud tops achieved larger heights and became colder.
Credit: NASA JPL, Ed Olsen
Tropical Storm Heidi's Temperature, Cloud Heights and Rainfall Grabbed by NASA Satellites

NASA satellites got a look inside Tropical Storm Heidi over the last several days and provided data that enabled forecasters at the Joint Typhoon Warning Center to know she was going to strengthen before making landfall, and she did.

Two instruments on NASA's Aqua satellite and two instruments on NASA's TRMM satellite provided forecasters with the rate at which rain was falling within Heidi, cloud heights and cloud and sea surface temperatures. All of those factors are added together to determine the behavior of a tropical cyclone. NASA data showed warm sea surface temperatures giving power to Heidi before landfall, and showed rainfall intensifying, indicating the tropical storm was gaining strength. Cloud heights and temperatures also clue forecasters in on a tropical storm's behavior, as the higher and colder the cloud tops, the more uplift (strength) and stronger the storm.

Heidi made landfall on January 11, 2012. On January, 12, 2012 at 8:54 p.m. AWST (local time, Western Australian), the Australian Bureau of Meteorology gave an "all clear" for Port Hedland, Cyclone warning for inland areas of central Pilbara. Now in effect is a cyclone warning for inland areas of the central Pilbara to the northeast of Tom Price.

Heidi continues to weaken as it moves further inland and is expected to be below Tropical Cyclone intensity later this afternoon or evening.

Over the days of January 10, 11, 12, 2012, infrared data from the Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite showed cloud top temperatures growing increasingly colder (purple is the coldest, greater than -63F) as Heidi strengthened and approached the Pilbara coastline. The images were taken at 16:59 UTC on Jan. 10; at 17:47 UTC on Jan. 11; and at 5:53 UTC on Jan. 12, 2012. When NASA's Aqua satellite passed over Heidi on January 12, another instrument aboard called the Moderate Resolution Imaging Spectroradiometer (MODIS) captured a visible image of the storm. The image showed that Heidi maintained her well-rounded shape and even appeared to hint at an eye in the center after making landfall on the Pilbara Coast of Western Australia.

NASA's Tropical Rainfall Measuring Mission (TRMM) satellite provides measurement of rainfall rates and cloud heights in the tropics, and both of those are very important in forecasting tropical cyclone behavior. TRMM measured the rainfall within Heidi on January 10 and 12 and noticed more areas of heavy rain on the twelfth as the storm intensified.

On January 10, 2012 at 1544 UTC (10:44 a.m. EST) the TRMM satellite passed above tropical storm Heidi as it was forming off the northwestern coast of Australia. Heidi is the first named tropical cyclone to hit Australia this season. An analysis of rainfall from TRMM Microwave Imager (TMI) and Precipitation Radar (PR) data showed that Heidi was starting to get organized with bands of heavy convective rainfall spiraling toward the center of the storm. Heidi was dropping rainfall at a rate of over 50mm/hr (~2 inches) in some areas.

In a 3-D image created by TRMM data on January 12, some powerful storms within Heidi were reaching heights above 15km (9.3 miles). Rainfall data from TRMM PR data revealed that Heidi's location was defined by a rain band circling the center of the storm. This analysis also showed that very heavy rainfall from Heidi's outer bands was hitting the Australian coast.

Heidi caused several thousand power outages in its passage. Over 4 inches (100 millimeters) of rainfall was reported near Hedland, causing flooding. There were some reports of isolated totals as high as almost 8 inches (200 millimeters) Of course, rivers and stream flooding may continue for a couple of days.

According to the Australian Broadcasting Corporation, Tropical Storm Heidi was Hedland's first cyclone since 2007. That's when Cyclone George hit the region and made landfall in the same exact location. George was a category four storm and Heidi reached Category 2. Heidi is now a remnant low pressure area far inland near Paraburdoo.

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



Jan. 11, 2012

Tropical Storm Heidi is forecast to make landfall today along the Pilbara coast of Western Australia as warnings pepper the coast. › Larger image
NASA's Aqua satellite passed over Heidi on January 11, 2012 at 02:30 UTC (Jan. 10 at 10:30 a.m. EST) and captured a visible image of the storm. The image showed that Heidi maintained her well-rounded shape and her center was just north of the Pilbara Coast of Western Australia.
Credit: NASA Goddard MODIS Rapid Response Team
NASA Sees Tropical Storm Heidi Approaching Australia's Pilbara Coast

Tropical Storm Heidi is forecast to make landfall today along the Pilbara coast of Western Australia as warnings pepper the coast. NASA's Aqua satellite passed overhead early in the day and captured a visible image showing Heidi's center still north of the Pilbara coast, while her outer bands continue to bring rainfall and gusty winds to coastal residents.

NASA's Aqua satellite passed over Heidi on January 11, 2012 at 02:30 UTC (Jan. 10 at 10:30 a.m. EST) and the Moderate Resolution Imaging Spectroradiometer captured a visible image of the storm. The image showed that Heidi maintained her well-rounded shape and her center was just north of the Pilbara Coast of Western Australia at that time.

There are several warnings in effect in Australia as Heidi approaches. According to the Australian Bureau of Meteorology (ABM), a Cyclone Warning is active for "coastal areas from Wallal to Dampier, including Port Hedland, Roebourne, Karratha and Dampier, and extends to adjacent inland parts." In addition, a Red Alert is up for the "coastal and island communities between Pardoo and Whim Creek, including the communities of Pardoo, Port Hedland, South Hedland, and Whim Creek." A Blue Alert is in effect for the "coastal and island communities between Whim Creek and Dampier, including the communities of Roebourne, Pt Samson, Karratha, and Dampier."

At 1500 UTC (10 a.m. EST) Heidi's maximum sustained winds have increased to 55 knots (63 mph/101 kmh. Heidi's center was still off-shore at about 45 nautical miles (52 miles/83 km) north-northeast of Port Hedland, Australia near 19.6 South and 118.9 East. Heidi was moving slowly at 4 knots (5 mph/7 kph) to the south-southwest.

NASA's Atmospheric Infrared Sounder (AIRS) instrument captured an image of Heidi at the same time as the MODIS instrument because they fly aboard the same satellite. The infrared data showed that Heidi was becoming more tightly wound. Forecasters using the AIRS data at the Joint Typhoon Warning Center noted that there is "convection gathering more directly over the top of the system."

Heidi is expected to strengthen a little more before making landfall because it's in an area of low vertical wind shear (winds that can weaken a storm or tear it apart) and sea surface temperatures warmer than needed to maintain a tropical cyclone. The sea surface temperatures off the Pilbara coast are near 30 degrees Celsius (86 F) and only 26.6C (80F) is needed to sustain a tropical cyclone. Anything warmer adds power to the cyclone through evaporation.

The ABM's forecast track for Heidi can be seen on their website at: http://www.bom.gov.au/products/IDW60281.shtml.

Heidi is expected intensify until it makes landfall. Landfall is expected today between Port Hedland and Point Samson. Heidi is expected to weaken after landfall as it heads to the south-southwest over the next couple of days.

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



Jan. 11, 2012

tropical storm Heidi in black and white NASA's Aqua satellite passed over Heidi on January 10, 2012 at 1706 UTC (12:06 p.m. EST) and captured in infrared image. The image showed that Heidi was a well-rounded shape indicating good organization. Credit: NASA/NRL
› Larger image
NASA Sees Tropical Storm Heidi Form, Port Hedland, Australia on Alert

The low pressure area in the Southern Indian Ocean named System 92P strengthened quickly today and was renamed Tropical Storm Heidi. NASA's Aqua satellite captured an infrared image of Heidi that showed her development.

During the afternoon (Eastern Daylight Time) on January 10, 2012, System 92P became Tropical storm Heidi. It was located about 170 miles north of Port Hedland, Australia, near 17.5S 118.9E. Maximum sustained winds were near 35 knots (40 mph) making it a minimal tropical storm. However, the Joint Typhoon Warning Center noted that conditions may allow it to strengthen before it makes landfall west of Port Hedland on January 11 before 1800 UTC (1 p.m. EST).

NASA's Aqua satellite passed over Heidi on January 10, 2012 at 1706 UTC (12:06 p.m. EST) and captured in infrared image. The image showed that Heidi was a well-rounded shape indicating good organization.

The Australian Bureau of Meteorology stated today that Heidi is headed toward the Pilbara coast, and "is expected to produce gales with gusts to [62 mph] 100 kilometers per hour in coastal areas from Port Hedland to Wallal early on Wednesday morning, extending west to Dampier later on Wednesday."

According to the Joint Typhoon Warning center, "Observations at Rowley Shoals indicate the winds have increased to at least 35 knots (40 mph) with central pressures near 996 millibars supporting the current intensity estimate."

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