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Hurricane Season 2010: Tropical Storm Hermine (Gulf of Mexico)
09.10.10
 
September 10, 2010

Tropical Storm Hermine

Estimate total rainfall between September 2 and September 8, 2010. › View larger image
Rainfall measurements from a variety of satellites, including NASA’s Tropical Rainfall Measuring Mission (TRMM) satellite.
Credit: NASA Earth Observatory, Jesse Allen
Though Tropical Storm Hermine brought strong winds and tornadoes to parts of Texas when it moved inland on September 7 and 8, the storm’s greatest hazard came from heavy rainfall. Hermine moved slowly, allowing rain-producing clouds to linger and rain to accumulate. The heavy rains triggered widespread flooding, including major flooding on the Trinity River in the Dallas region, said the National Weather Service.

The storm’s path inland over Texas and into Oklahoma and Arkansas is clearly defined in this rainfall image. The image shows rainfall measurements from a variety of satellites, including NASA’s Tropical Rainfall Measuring Mission (TRMM) satellite. The TRMM-calibrated Multi-satellite Precipitation Analysis collated the measurements to estimate total rainfall between September 2 and September 8, 2010. The heaviest rain fell shortly after Hermine came ashore, but a swath of heavy rain also followed the storm north.

Text credit: Holli Riebeek, NASA's Earth Observatory



September 09, 2010

TRMM Satellite Measures Hermine's Severe Texas Rainfall from Space

Rainfall accumulation accumulated for seven days from September 2 through Sept. 9. › View larger image
This rainfall accumulation map represents TRMM data accumulated for seven days from September 2 through Sept. 9. Hermine's track and storm symbols are in white. Rainfall totals in the Gulf of Mexico off the Texas coast showed over 225 mm (8.9 inches) had fallen. The heaviest rainfall over land was in an isolated area northeast of the storm's track where over 250 mm (~ 10.0 inches) fell in southeastern Texas.
Credit: NASA/SSAI, Hal Pierce
On Sept. 8, 2010, Hermine was dropping over 50 mm/hr (~ 2 inches) of heavy rainfall (in red). › View larger image
This TRMM image shows the rate of rain falling in Tropical Storm Hermine on Sept. 8, 2010 over Texas. Hermine was dropping over 50 mm/hr (~ 2 inches) of heavy rainfall (in red). The yellow and green areas indicate moderate rainfall between .78 to 1.57 inches per hour.
Credit: NASA/SSAI, Hal Pierce
The Tropical Rainfall Measuring Mission satellite estimates rainfall from space and has provided NASA and other scientists with a visual tool to see just how much Tropical Storm Hermine has drenched Texas with since it made landfall earlier this week. .

Tropical storm Hermine maintained its organization after coming ashore in northeastern Mexico and southeastern Texas. On its northward track, Hermine dumped excessive rainfall, created flooding and was the cause of more than 100 high-water rescues so far this week. The National Weather Service in San Antonio/Austin reported multiple homes flooded and multiple water rescues in the towns of Devine and Natalia..

The Tropical Rainfall Measuring Mission satellite, also known as TRMM, passed above Hermine from space every day this week and captured data on its rainfall rates and total rainfall. TRMM is operated by NASA and the Japanese Space Agency, JAXA, and is used to study tropical cyclones. TRMM can assess the rate at which rain is falling from a storm and the total rainfall over tropical areas on Earth. That data is used by visualizers and scientists like Hal Pierce at NASA's Goddard Space Flight Center in Greenbelt, Md. to create flood maps and rainfall rate maps. .

Hal created a map of rainfall rates and a map of rainfall accumulations from Sept. 2 through mid-day on Sept. 9, 2010 that depicted Hermine's rainfall totals over Texas and Oklahoma using measurements from a variety of satellites, including NASA’s Tropical Rainfall Measuring Mission (TRMM) satellite.

The map also showed Tropical Storm Hermine's track and appropriate storm symbols of the storm's strength. The TRMM rainfall totals off the Texas coast in the Gulf of Mexico showed that over 225 mm (8.9 inches) of rain had fallen there. TRMM data showed that the heaviest rainfall over land was in an isolated area northeast of the storm's track where over 250 mm (~ 10.0 inches) fell in southeastern Texas where Hermine pumped moisture laden air inland..

Rainfall totals reported from National Weather Service locations in some areas of Texas ranged from 4.34 to 7.04 inches. Some higher totals were recorded outside of those areas. The National Weather Service office in San Antonio, Texas reported 2.83 inches of rainfall on Sept. 8 and 3.69 inches on Sept. 7, totaling 6.52 inches over two days from Hermine. The Austin/Bergstrom National Weather Service office reported .78 inches of rain on Sept. 7, 3.54 inches on Sept. 6 and .02 on Sept. 5 totaling 4.34 inches. The Austin/Mabry NWS reporting station coincided with the total rainfall data that TRMM gathered from space, on Sept. 7 .51 inches of rain fell, Sept. 6, 7.04 inches, and on Sept. 5, .02 inches fell, totaling 7.57 inches. .

In addition to the overwhelming rainfall, Hermine's remnants also produced tornadoes. The National Weather Service in Austin/San Antonio confirmed a tornado near the town on Moulton in Lavaca County on Sept. 7. As many as three tornadoes were already reported in Oklahoma, and a flash flood watch is now in effect in that state as Hermine continues to move northeast. Because the heavy rainfall associated with the system continues to move with it, Flood watches are also in effect for areas of Arkansas, Missouri and Kansas.

Text credit: Rob Gutro, NASA's Goddard Space Flight Center, Greenbelt, Md. and Hal Pierce, SSAI



September 08, 2010

NASA's TRMM Satellite Maps Flood Potential from Tropical Depression Hermine

TRMM's rainfall measurements and various reporting station data were used to create this flood potential map. › View larger image
TRMM's rainfall measurements and various reporting station data were used to create this flood potential map. The yellow area on the map depicts areas with flood potential, while the orange areas indicate flooding occurring now. Severe flood potential areas are depicted in red, but there were none for Texas on Sept, 8.
Credit: NASA/SSAI, Hal Pierce
This visible image of Tropical Storm Hermine was captured by the MODIS on September 7. › View larger image
MODIS CAPTION: This visible image of Tropical Storm Hermine was captured by the MODIS instrument on NASA's Terra Satellite at 17:25 UTC or 12;25 p.m. CDT on September 7 as it was making its way north through Texas and dropping heavy rainfall.
Credit: NASA MODIS Rapid Response Team
Tropical cyclones are usually big rainmakers once they make landfall and they start to fizzle out, and Hermine, now a tropical depression over Texas is no exception. Rainfall data on Hermine's heavy rains were gathered by NASA and the Japanese Space Agency's Tropical Rainfall Measuring Mission (TRMM) satellite. That data was used to create a map of potential flood areas that showed areas of flooding and potential flooding over a large area in southeastern and central Texas.

NASA's Tropical Rainfall Measuring Mission (TRMM) satellite provides rainfall data from its perch in orbit above the Earth. TRMM has been called a "rain gauge in space" and can provide accurate measurements of rainfall in tropical and sub-tropical areas around the world.

Hal Pierce of NASA's TRMM team at the NASA Goddard Space Flight Center in Greenbelt, Md. used the rainfall data from TRMM's rainfall measurements and various reporting stations to create a flood potential map. The map is color-coded and depicts areas with severe flood potential on Sept, 8.

Several areas in southeastern Texas where Hermine continues to drop heavy rainfall are designated as flooding areas while other areas have flood potential. Some of the rainfall totals reported include 130mm (5.18 inches) from Port O'Connor, Texas; 153mm (6.02 inches) from San Antonio; and 172mm (6.77 inches) from San Marcos.

At 11 p.m. EDT on Sept. 7, the National Hurricane Center in Miami, Fla. issued their last advisory on Hermine, when it was centered near 31.6 North and 99.5 West. Hermine still had maximum sustained winds near 34 mph at that time and a minimum central pressure of 1003 millibars. Hermine was still moving north at 15 mph.

By 8 a.m. EDT on Sept. 8, NOAA's Hydrometeorological Prediction Center noted that "heavy rain associated with Tropical Storm Hermine has been impressive early this morning over Texas...especially within a narrow band that developed along and west of Interstate-35 where 6 to 10 inches has fallen west of Austin as of 8 a.m. CDT this morning.

The National Weather Service for Austin/San Antonio issued a Flash Flood Watch for much of south central Texas and the hill country through 6 p.m. CDT today, September 8.

The moisture associated with now Tropical Depression Hermine is forecast to continue to bring heavy flooding rains northward into Oklahoma today. Those heavy rains are expected to move into southeast Kansas and Missouri by Friday morning, and all of these areas are under flood or flash flood watches.

By Thursday night, September 9, Hermine's surface low pressure area is forecast to dissipate into a frontal zone, but its upper level circulation will continue moving to the east, bringing with it a potential for some isolated areas of heavy rainfall.

For more information about how TRMM looks at rainfall, visit NASA's TRMM website at: http://trmm.gsfc.nasa.gov//. TRMM is a joint mission between NASA and the Japanese space agency JAXA.

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



September 07, 2010

NASA Saw Strong T-storms in Quick-Forming Hermine's Center, Warm Water to Power It

Tropical Storm Hermine right after she formed on Sept. 6 with strong convection and strong thunderstorms around the center of circulation. › View larger image
Infrared imagery from NASA's AIRS instrument captured Tropical Storm Hermine right after she formed on Sept. 6 at 19:53 UTC (3:53 p.m. EDT), showed strong convection and strong, high thunderstorms (Purple) around the center of circulation indicating an organized tropical storm.
Credit: NASA/JPL, Ed Olsen
The large extent of Tropical Storm Hermine's clouds stretching north into Oklahoma, Missouri and Arkansas, and south into northern Mexico. > View larger image
This visible image from the GOES-13 satellite at 11:31 UTC (7:31 a.m. EDT) on Sept. 7, 2010, shows the large extent of Tropical Storm Hermine's clouds stretching north into Oklahoma, Missouri and Arkansas, and south into northern Mexico.
Credit: NOAA/NASA GOES Project
Tropical Storm Hermine formed very quickly yesterday in the very warm waters of the Gulf of Mexico, and northeastern Mexico and southeastern Texas are now bearing the brunt of the storm. Infrared imagery taken from NASA's AIRS instrument showed a quick organization of strong thunderstorms around Hermine's center of circulation and very warm Gulf waters that powered her up.

At 11 p.m. EDT on September 6, Hermine made landfall as a strong tropical storm producing heavy rains over northeastern Mexico and South Texas.

This morning there's a tropical storm warning in effect from Bahia Algodones, Mexico Northward to Port O'Connor, Texas as Hermine is continuing to move inland in a north-northwest direction at 17 mph. At 8 a.m. EDT, Hermine's maximum sustained winds had decreased from their peak of 60 mph to 45 mph now that she's over land in south Texas. She's centered near 27.7 North and 98.2 West, which is about 35 miles southwest of Mathis, Texas. Mathis is about 171 miles north of Brownsville, Texas, the southernmost city in the state. Minimum central pressure is 991 millibars.

Tropical Storm Hermine formed quickly in the extreme western Gulf of Mexico on Labor Day in the U.S., Monday, September 6. On Friday, Sept. 4, forecasters were watching a low pressure area, and two days later, even close to the coast tropical depression 11 formed and quickly strengthened into a tropical storm.

Infrared imagery from NASA's Aqua satellite instrument the Atmospheric Infrared Sounder (AIRS) captured Tropical Storm Hermine right after she formed on Sept. 6 at 19:53 UTC (3:53 p.m. EDT), showed strong convection and strong, high thunderstorms around the center of circulation indicating an organized tropical storm. AIRS data also showed that that sea surface temperatures where Hermine formed yesterday were about 86 degrees Fahrenheit (30 Celsius), way above the 80F threshold needed to power a tropical cyclone.

A large threat from Hermine is extreme rainfall. She's expected to produce between 4 and 8 inches of rain with isolated totals up to 12 inches from southern Texas northward through northern Texas and into central and eastern Oklahoma. The National Hurricane Center noted that the rains are expected to continue spreading northeastward into Kansas, northwestern Arkansas and Missouri over the next few days and could caused life-threatening flash floods.

The visible satellite image from the GOES-13 satellite at 11:31 UTC (7:31 a.m. EDT) on Sept. 7, 2010, showed the large extent of Tropical Storm Hermine's clouds stretching north into Oklahoma, Missouri and Arkansas, and south into northern Mexico. GOES-13 is one of the Geostationary Operational Environmental Satellites operated by NOAA. NASA's GOES Project at NASA's Goddard Space Flight Center, in Greenbelt, Md. creates images and animations from GOES satellite data.

Meanwhile, tropical-storm force winds are expected in the warning area, and isolated tornadoes are possible across portions of southeast Texas through today.

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