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Kristy Regains Tropical Storm Strength

At 11:00 a.m. EDT (1500 UTC) September 5, the center of Tropical Storm Kristy was near latitude 16.4 north, longitude 121.5 west in the east Pacific; traveling west-southwest at 8 mph (7 knots) with maximum sustained winds near 40 mph.

After weakening to a tropical depression, strong thunderstorms developed near Kristy's center earlier on Sept. 5 and have persisted for several hours. While forecasters say the overall environment does not support significant strengthening as dry air may begin feeding into the storm's circulation, Kristy will likely remain over warm waters and maintain its current strength over the next several days.

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An Inside Look of Tropical Storm Kristy's Clouds


Click on image to enlarge.

This is an infrared image of Tropical Storm Kristy, from the Atmospheric Infrared Sounder (AIRS) on NASA's Aqua satellite on September 1, 2006. This AIRS image shows the temperature of the cloud tops or the surface of the Earth in cloud- free regions. The lowest temperatures (in purple) are associated with high, cold cloud tops that make up the top of the storm. The infrared signal does not penetrate through clouds. Where there are no clouds the AIRS instrument reads the infrared signal from the surface of the Earth, revealing warmer temperatures (red). Image Credit: NASA/JPL -- Caption: NASA/RSIS, Mike Bettwy

Where is Kristy on Fri. Sep. 1?

At 1500 UTC (11:00 a.m. EDT) the center of Tropical Storm Kristy was near latitude 19.3 north, longitude 118.3 west in the east Pacific and is traveling west-northwest at 6 mph (5 knots) with maximum sustained winds near 55 mph.

The Future of Kristy

Kristy is expected to continue its weakening trend as it traverses cooler water and vertical shear from Hurricane John. As it interacts with a more stable environment, it should weaken to a remnant low within 3 days. Movement should remain slow, with a general trend toward the southwest.

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Hurricanes John and Kristy Put Mexico on Alert

The 2006 East Pacific hurricane season is now in full swing with 2 active storms in the heart of the season. The total number of named storms so far is near the climatological average and near the number from last year. Recently, Tropical Storm Kristy became the 11th named storm of the 2006 season. However, in terms of intense storms, this year's pace is well above normal and far outdistances the 2005 season. When Hurricane John reached Category 3 intensity on the 29th of August 2006, it became the 5th major hurricane of the season. There were only two major hurricanes in 2005 with four being the typical average for the entire season.

Category Three Winds Expected to Affect the Mexican Coast from John

At 5:00 a.m. PDT the center of Hurricane John was located near latitude 19.0 north, longitude 105.8 west or about 95 miles west of Manzanillo, Mexico and about 100 miles south of Cabo Corrientes, Mexico. John is moving toward the west-northwest near 14 mph, however, a small deviation in the track could bring the center onshore within the hurricane warning area. Although the center of John is forecast to remain offshore, winds to hurricane force are expected within the hurricane warning area. Maximum sustained winds are near 125 mph with higher gusts. John is a category three hurricane on the Saffir-Simpson scale. Estimated minimum central pressure is 950 millibars, and rainfall amounts of 6 to 10 inches with isolated amounts to 18 inches are possible in the warning areas. Coastal storm surge flooding of up to 5 feet above normal tide levels along with large and dangerous battering waves can be expected near the center of John.

Hurricane Warnings Posted in Mexico

At 0900 UTC (2:00 a.m. PDT) on Thurs. Aug. 31, a hurricane warning is in effect along the Pacific coast of mainland Mexico from Lazaro Cardenas to San Blas and for Islas Marias. A hurricane warning is also in effect for the Southern Baja Peninsula from La Pas southward on the east coast, and from Santa Fe southward on the west coast. A tropical storm warning is in effect from San Blas to Mazatlan, Mexico.

What's Happening in Mexico?

On Aug. 31, Mexican authorities notified coastal area residents in Jalisco and Michoacan to prepare for hurricane conditions. Authorities in Jalisco ordered the evacuation of 8,000 people and urged others to board up their homes. Winds and rain already uprooted trees and caused mudslides in the seaside tourist resort of Acapulco.

Hurricane Kristy West of Hurricane John, in the Open Pacific Waters At 0900 UTC (2:00 a.m. PDT) on Thurs. Aug, 31, Hurricane Kristy was located near 17.6 north and 116.1 west, moving to the northwest near 5 knots (6 mph). Kristy's maximum sustained winds are near 65 knots (74 mph) making her a category one storm. The National Hurricane Center expects further strengthening in the next 24 hours. At present, her minimum central pressure is 987 millibars.

A Satellite View of the Storms

The Tropical Rainfall Measuring Mission satellite (known as TRMM) was placed into service in November of 1997. From its low-earth orbit, TRMM can provide valuable images and information on tropical cyclones around the Tropics using a combination of passive microwave and active radar sensors. TRMM is well-suited to help monitor hurricane activity in the East Pacific.

Currently, powerful Hurricane John, which reached Category 4 intensity on the 30th, is still offshore but dangerously close to the west coast of Mexico.

 
Click on images to enlarge.

This first image was captured by TRMM at 02:47 UTC 30 August (7:47 pm PDT 29 August) 2006. It shows the horizontal distribution of rain intensity (top down view) within John as viewed by TRMM. Rain rates in the center of the swath are from the TRMM Precipitation Radar (PR), and 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). It is evident from this image that John has a well-organized, intense circulation as supported by the tight banding (curvature) in the rain bands (green arcs with areas of red, which indicate bands of moderate rain with areas of heavy rain) surrounding a well-defined eye with a complete inner eyewall (inner most green ring). At the time of this image, John was still a Category 3 hurricane with maximum sustained winds reported at 100 knots (115 mph) by the National Hurricane Center (NHC).

John is forecast to remain just offshore but very close to Mexico before approaching the southern tip of Baja California later in the week.

Meanwhile, about 1600 kilometers off to the west, Tropical Storm Kristy is gaining strength. This next image was taken by TRMM at 12:35 UTC (5:35 am PDT) on the 30th of August as Kristy was passing well to the southwest of Cabo San Lucas heading away from land. TRMM reveals a small but fairly well-organized storm. Although the rain field is confined close to the center, a strong rain band (red arc) wraps around the western side of the storm and indicates an area of active convection near the core, a necessary ingredient for intensification.

 
Click on images to enlarge.

The TRMM PR has the ability to look at precipitation structures in the vertical. This final image shows a coincident vertical cross section through the center of Kristy from the TRMM PR. The PR reveals areas of deeper convection associated with the heavy rain at the surface. Kristy is forecast to strengthen into a hurricane but does not pose an immediate threat to any land areas. 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).