Hurricane Paul, now the 10th hurricane of the season in the East Pacific, is poised to recurve and could threaten the southern tip of Baja California or the west coast of Mexico in the coming days. Paul began as a tropical depression during the early morning hours of 21 October 2006 (local time) about 265 miles south-southwest of Manzanillo, Mexico. Paul became a weak tropical storm later on the 21st before reaching hurricane intensity on the afternoon (local time) of the 22nd.

From its low-earth orbit, TRMM has been providing valuable images and information on tropical cyclones around the Tropics, especially over open ocean where direct observations are limited. TRMM captured this image of Paul as the storm was transitioning from a tropical storm into a hurricane. The image was taken at 00:15 UTC 23 October (5:15 PDT 22 October) 2006 and shows the horizontal distribution of rain intensity (top down view) within Paul. Rain rates in the center of the swath come from the TRMM Precipitation Radar (PR), while those in the outer swath are from the TRMM Microwave Imager (TMI). These rain rates are overlaid on infrared (IR) data from the TRMM Visible Infrared Scanner (VIRS). A small eye is visible near the center of the storm with several moderate intensity rainbands (green arcs) spiraling inwards from the south. These are the tell tale signs of a developed circulation. Scattered areas of heavy rain (shown in red) are also evident, including one which is located in the eyewall just to the east of the center.

See a 3-D flyby of the 15dBZ isosurface image above

A second image from the same overpass shows a 3D view of the storm courtesy of the TRMM PR. The PR is a one-of-a-kind vertically-scanning space-borne precipitation radar. It can provide information on the storm's vertical structure. TRMM reveals that the area of intense rain in the eyewall that was visible in the previous image is associated with a deep convective tower (shown in red). Such towers can be a sign of future intensification especially when they are located near the core of the storm as is the case here with Paul. This area of deep convection is releasing heat into the storm. This heating, known as latent heating, is what lowers the storm's central pressure and drives the circulation. At the time of these images, the National Hurricane Center (NHC) estimated Paul to have sustained winds of 55 knots (63 mph). Paul became a hurricane just a few hours later.

Paul continued to strengthen and reached Category 2 intensity the next day on the 23rd with sustained winds increasing to 95 knots (109 mph). The storm is expected to recurve ahead of a deep-layer trough located off of the West Coast. This is expected to bring the storm close to the southern tip of Baja California. Paul is also forecast to weaken before making landfall due to increasing wind shear.

25 OCTOBER UPDATE HURRICANE PAUL DOWNGRADED TO TROPICAL STORM
Hurricane PAUL was downgraded to a tropical storm on 24 October 2006. Paul weakened further to a tropical depression and hit the coast of Mexico north of Mazatlan on 26 October 2006. The image on the right was made from data received by the TRMM satellite at 00:03 UTC 25 October (5:03 PDT 25 October) 2006 and shows the horizontal distribution of rain intensity (top down view) within Paul.

26 OCTOBER UPDATE TROPICAL DEPRESSION PAUL FLOOD POTENTIAL
Tropical storm Paul, which had weakened to a tropical depression, dissipated after hitting the Mexican Coast north of Mazatlan on 26 October 2006. The TRMM based potential flood map above shows rainfall totals of over 200mm (7.9 inches) in west-central Mexico. The last image display on the right was made using downloads of TRMM based "realtime" flood potential images in the GOOGLE EARTH program.



TRMM is a joint mission between NASA and the Japanese space agency JAXA. Images produced by Hal Pierce (SSAI/NASA GSFC) and caption by Steve Lang (SSAI/NASA GSFC).