Thursday, July 24, 2008

Hurricane Season 2008: Tropical Storm Dolly (Gulf of Mexico)


Hurricane Dolly Already Making Landfall; Tornado Reported in South Texas


Tropical Storm Dolly strengthened into a Category One Hurricane with 85 mph maximum sustained winds and may get even stronger before her eye makes landfall this morning (July 23, 2008). Dolly's center will be along the coast near the Texas/Mexico border around midday today, according to the National Hurricane Center, but she's already generated one tornado in south Texas this morning.

At 7:00 a.m. EDT, tropical storm force winds were already affecting coastal Texas and northeastern Mexico. The center of hurricane Dolly was located near latitude 25.8 north and longitude 96.6 west or about 55 miles (90 km) east of Brownsville, Texas.

Dolly is moving toward the northwest near 8 mph (13 km/hr) and northwestward to west-northwestward motion with a slight decrease in forward speed is expected today. Minimum central pressure is 972 millibars.

Where are the Warnings and Watches?

A hurricane warning remains in effect for the coast of Texas from Brownsville to Corpus Christi and for the northeastern coast of Mexico from Rio San Fernando northward to the border between Mexico and the U.S. Tropical Storm Warnings are posted for areas north and south of the hurricane warning area.

What Weather Conditions Are Expected?

At 8:00 a.m. EDT, the city of Brownsville, Texas was under a Flood Watch, Hurricane Wind Warning, Tornado Watch, and already a Tornado Warning.

At 7:04 a.m. CDT, The National Weather Service doppler radar indicated a tornado 7 miles north of Harlingen Valley Airport and moving southwest at 46 mph.

In the warning areas, Dolly is expected to produce total rainfall accumulations of 6 to 10 inches, with isolated amounts of 15 inches over portions of south Texas and northeastern Mexico over the next few days. These rains will likely cause widespread flooding across portions of south Texas and northeast Mexico.

Coastal flooding is another problem. Dolly's storm surge along the coasts will range from 4 to 6 feet above normal tide levels. There will also be large and dangerous battering waves near and north of the center's landfall point.

As with any land-falling hurricane, isolated tornadoes are also possible. Portions of south Texas and northern Mexico may experience isolated tornadoes today and tonight.

For Current Radar out of Brownsville, Texas, visit:

http://radar.weather.gov/radar.php?rid=BRO&product=NCR&overlay=11111111&loop=yes

What Does This NASA Satellite Image Show?

This infrared image of Dolly was created by data from the Atmospheric Infrared Sounder (AIRS), an instrument that flies aboard NASA's Aqua satellite. The image was created on July 22 at 19:05 UTC (3:05 p.m. EDT) and Dolly was located in the Gulf of Mexico headed toward the Texas/Mexico border. Dolly is seen to the left side of this image.

The AIRS images show 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 Dolly. The AIRS data creates an accurate 3-D map of atmospheric temperature, water vapor and clouds, all of which are helpful to forecasters.

The infrared signal of the AIRS instrument does not penetrate through clouds. Where there are no clouds the AIRS instrument reads the infrared signal from the surface of the ocean waters, revealing warmer temperatures in orange and red.


Dolly Poised to Hit South Texas, Northern Mexico as Hurricane

The 2008 Atlantic hurricane season has become a lot more active recently, first with the formation of Tropical Storm Cristobal off of the Carolina coast and now with Tropical Storm Dolly in the Gulf of Mexico poised to strike near the border between Texas and Mexico. Dolly, which became a tropical storm in the western Caribbean on the morning (local time) of 20 July 2008, originated from an African easterly wave that had emerged off of the coast of Africa back on the 12th of July before propagating westward across the tropical Atlantic and into the Caribbean. After forming in the western Caribbean, Tropical Storm Dolly maintained a generally west-northwestward track, which took the center across the very northern tip of the Yucatan Peninsula early on the morning (local time) of July 21st. Despite passing over land and being somewhat disorganized, Dolly maintained moderate tropical storm intensity with sustained winds estimated at 45 knots (52 mph) by the National Hurricane Center (NHC). Dolly re-emerged over the warm open waters of the western Gulf of Mexico later on the morning of the 21st. Combined with low atmospheric wind shear, conditions were favorable for intensification. The only real inhibiting factor was the sprawling nature of the storm itself. Without a well-organized core, storms take longer to respond to favorable conditions. None-the-less, Dolly began to slowly strengthen as is took aim at the Texas-Mexico border.

The Tropical Rainfall Measuring Mission satellite (also known as TRMM) has been in service for over 10 years now and continues to provide valuable images and information on tropical cyclones around the Tropics using a combination of passive microwave and active radar sensors, including the first precipitation radar in space. These unique images were captured by TRMM at 12:44 UTC (7:44 am CDT) 22 July 2008 while Dolly was in the western Gulf of Mexico. The first image shows the horizontal pattern of rain intensity within the storm. Rain rates in the center swath are based on the TRMM Precipitation Radar (PR), and those in the outer swath on the TRMM Microwave Imager (TMI). The rain rates are overlaid on infrared (IR) data from the TRMM Visible Infrared Scanner (VIRS). TRMM reveals that Dolly has a rather large wavy eye with most of the moderate to heavy rain (green and red areas, respectively) wrapping around the southern side of the storm.

The second image was collected at the same time and shows a 3D perspective of the storm via the TRMM PR. The eye is clearly visible by the deep center (in blue), which is completely surrounded by a ring of moderately high precipitation areas (green). A few somewhat taller towers are visible in red within the eastern eyewall. At the time of these images, Dolly was a moderate tropical storm with maximum sustained winds reported at 55 knots (63 mph) by NHC. Dolly is expected to continue off to the west-northwest and make landfall in the vicinity of Brownsville, TX as a minimal hurricane before turning more westward over central northern Mexico.

TRMM is a joint mission between NASA and the Japanese space agency JAXA.


Dolly Eyeing Landfall Wednesday at Texas/Mexico Border as a Hurricane

Tropical Storm Dolly is strengthening in the warm waters of the Gulf of Mexico, and is expected to become a hurricane by Wednesday, July 23. The National Hurricane Center is forecasting landfall that day near Brownsville, Texas, which is on the border between Texas and Mexico.

Where is Dolly Now?
At 5:00 a.m. EDT (4:00 a.m. CDT) on Tuesday, July 22, the center of Tropical Storm Dolly was located near latitude 23.3 north and longitude 93.8 west or about 295 miles (475 km) southeast of Brownsville, Texas. Dolly's maximum sustained winds are near 60 mph (95 km/hr) with higher gusts. Additional strengthening is forecast, and Dolly is expected to become a hurricane prior to landfall.

Dolly is moving toward the west near 15 mph (24 km/hr). Later today, July 22, she's expected to turn to the west-northwest is expected later today, then veer northwest on the 23rd. Minimum central pressure is 997 millibars.

Where Are The Warnings Posted?
A hurricane warning is in effect for the coast of Texas from Brownsville to Port O'Connor. There's a warning also for the northeast coast of Mexico from Rio San Fernando, northward to the border between Mexico and the U.S. A hurricane warning means that hurricane conditions are expected within the warning area within the next 24 hours.

A tropical storm warning is in effect from north of Port O'Connor to San Luis Pass. A tropical storm warning means that tropical storm conditions (winds between 39-73 mph) are expected within the warning area within the next 24 hours.

What Will Dolly Bring to Texas and Mexico?
Like the Dolly Parton song "Wild Texas Wind" from her "Something Special" album of 1995, Texas and Mexico will likely be experiencing hurricane force winds over the next few days.

The National Hurricane Center expects Dolly to produce total rain accumulations of 4 to 8 inches with isolated amounts of up to 15 inches over much of south Texas and northeastern Mexico over the next few days. Dolly is expected to produce additional amounts of 1 to 3 inches over the Northern Yucatan Peninsula.

Dangerous coastal conditions are expected as Dolly approaches the coast. Coastal storm surge flooding of 4 to 6 feet above normal tide levels along with large and dangerous battering waves can be expected near and to the north of where the center makes landfall.

What Does This NASA Satellite Image Show?
This infrared image of Dolly was created by data from the Atmospheric Infrared Sounder (AIRS), an instrument that flies aboard NASA's Aqua satellite. The image was created on July 22 at 8:05 UTC (4:05 a.m. EDT) and Dolly is located in the Gulf of Mexico, some 275 miles southeast of Brownsville, Texas (at the southern-most tip of the state).

The AIRS images show 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 Dolly. The AIRS data creates an accurate 3-D map of atmospheric temperature, water vapor and clouds, all of which are helpful to forecasters.

The infrared signal of the AIRS instrument does not penetrate through clouds. Where there are no clouds the AIRS instrument reads the infrared signal from the surface of the ocean waters, revealing warmer temperatures in orange and red.


Tropical Storm Dolly, Here You Come Again…

Like the number one song by Dolly Parton, "Here You Come Again," six years ago, there was a tropical storm Dolly, now the name has returned on the official six year name hurricane list. Dolly is the name of the Atlantic Hurricane Season's fourth named storm and she means business in the Gulf of Mexico.

Dolly started out as a tropical depression on Sunday, July 20th and by 11:45 a.m. EDT that day, she strengthened into a tropical storm and got her name.

By 8:00 a.m. EDT on Monday, July 21, 2008, Dolly had moved off the Yucatan Peninsula, Mexico, and is located between there and Cuba. She's now poised to enter the Gulf of Mexico's warm waters and could become a hurricane by Tuesday, July 22.

At 8:00 a.m. EDT on July 21, Dolly's center was located near 21.6 degrees north latitude and 88.7 degrees west longitude, or 65 miles (105 km) east-northeast of Progreso, Mexico. Dolly is moving toward the west-northwest near 16 mph (26 km/hour), and a west-northwest motion is expected over the next couple of days. She's also expected to slow down in forward speed.

Dolly's maximum sustained winds are near 50 mph (85 km/hour) with higher gusts, and the warm waters of the Gulf of Mexico will strengthen her into a hurricane over the next day. Her estimated minimum central pressure is 1005 millibars.

She's expected to produce a good amount of rainfall across the northern Yucatan and western Cuba, between 4 and 6 inches. There will also be areas that could receive as much as 10 inches of rain.

This infrared image of Dolly was created by data from the Atmospheric Infrared Sounder (AIRS), an instrument that flies aboard NASA's Aqua satellite. The image was created on July 21 at 7:23 UTC (3:23 a.m. EDT) and Dolly is located between the Yucatan and Cuba poised to enter the Gulf of Mexico.

The AIRS images show 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 Dolly. The AIRS data creates an accurate 3-D map of atmospheric temperature, water vapor and clouds, all of which are helpful to forecasters.

The infrared signal of the AIRS instrument does not penetrate through clouds. Where there are no clouds the AIRS instrument reads the infrared signal from the surface of the ocean waters, revealing warmer temperatures in orange and red.

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