Tropical Cyclone Monty , February 29, 2004 1531UTC (CLICK TO ENLARGE)	Tropical Cyclone Monty (PR) March 1, 2004 1435UTC(CLICK TO ENLARGE)
Tropical Cyclone Evan March 1, 2004 0450UTC (CLICK TO ENLARGE)	Rain Accumulation February 23 - March 1, 2003(CLICK TO ENLARGE)

Two tropical cyclones made landfall in Australia just hours apart. Cyclone Monty came ashore along the northwest coast of Western Australia on the evening of 1 March 2004 (LST) while Cyclone Evan made landfall a little while later in the early morning hours of March 2nd (LST) along the east coast of the Northern Territory. Monty formed into a tropical depression at 18Z on the 26th of February from an area of low pressure that moved off of the coast of Western Australia and into the Indian Ocean. The depression strengthened into a tropical storm by 06Z on the 27th and continued heading westward parallel to the coastline. It also continued to intensify. By 12Z on the 29th, Monty had become a powerful cyclone with sustained winds estimated at 125 mph. It was rated as a Category 4 Cyclone by the Bureau of Meteorology's Tropical Cyclone Warning Center in Perth. An advancing cold front coming up from the southwest then steered Monty back towards the coastline, towards the southeast, where it then came ashore as a strong Category 3 storm near the town of Mardie. Meanwhile, Cyclone Evan formed in the Gulf of Carpentaria becoming a depression on the 29th. Evan also moved westward but did not become nearly as strong achieving Category 1 status at 7 pm LST on the 1st of March just before crossing the island of Groote Eylandt. Evan then hit the mainland on the east coast of the Northern Territory early the next morning while still a Category 1 storm according to the Tropical Cyclone Cyclone Warning Center in Darwin.

The Tropical Rainfall Measuring Mission (TRMM) satellite captured several unique images of these two cyclones. The first image shows Cyclone Monty off of the coast of Western Australia, north of Barrow Island. The image was taken at 15:31 UTC on 29 February 2004 (11:31 pm Australian WST). At the time, Monty was a powerful Category 4 cyclone. The image shows the horizontal distribution of rain rates as seen from overhead by the TRMM satellite. Rain rates in the center swath are from the TRMM Precipitation Radar (PR), the first precipitation radar in space, while rain rates in the outer swath are from the TRMM Microwave Imager (TMI). The rain rates are overlaid on infrared (IR) data from the TRMM Visible Infrared Scanner (VIRS). The center of Monty falls within the TMI swath in this image, and the TMI does not have as fine a resolution as the PR. However, the TMI does shows some heavy rainfall (red area) on the northwest side of the eye. Tropical cyclones rely on the heat that is released when water vapor condenses into cloud droplets to drive their circulation. These smaller droplets eventually form into larger raindrops that are easier to observe. The next image, taken at at 14:35 UTC on the 1st of March, captures Monty just as it was hitting the coast. The image also shows rainrates overlaid on IR data as before, only now the PR passes directly over the center of the storm. TRMM shows that Monty still has a tight, well-organized circulation with a closed eye still visible and good banding surrounding the center. These bands are evident in the green areas associated with moderate rainrates. TRMM reveals that the bulk of the heavier rainfall (green areas) is on the left hand side of the storm as it is making landfall. TRMM also captured a remarkable image of Cyclone Evan just as it was entering Dalumbu Bay before crossing Groote Eylandt. This image was taken at 04:50 UTC on 1 March. Although it shows an area of intense rainfall (darker reds) near the center of Evan that could fuel the storm, the tight banding seen in Monty is not apparent and Evan is too close to land for it to have a chance to intensify.

The TRMM-based, near-real time Multi-satellite Precipitation Analysis (MPA) at the NASA Goddard Space Flight Center monitors rainfall over the global tropics. MPA rainfall totals are shown for northern Australia in association with these two cyclones for the period 23 February to 1 March 2004. A swath of heavy rainfall (red areas) on the order of 8 to 12 inches is observed mainly offshore in association with Monty though some heavy and moderate (green areas) totals are evident over the coast. The rain associated with Evan, however, is embedded within a broad area of moderate (green areas) rainfall with locally heavier amounts (red areas) covering the Gulf of Carpentaria, the Northern Territory and northern Queensland.

See SMALLER [.3 mb] QUICKTIME ANIMATION of accumulation See MEDIUM 3-D [.8 mb] MPEG ANIMATION of accumulation

Large (7 mb)Tropical Cyclone Monty PRECIPITATION RADAR VERTICAL SLICES ANIMATION See SMALLER [.8 mb] QUICKTIME ANIMATION of Tropical Cyclone Monty PRECIPITATION RADAR vertical slices See MEDIUM 3-D [1.7mb mb] MPEG ANIMATION of PRECIPITATION RADAR vertical slice

TRMM is a joint mission between NASA and the Japan Aerospace Exploration Agency (JAXA).

Images produced by Hal Pierce (SSAI/NASA GSFC) and caption by Steve Lang (SSAI/NASA GSFC).