May 31, 2013



-> NASA Satellites Watch the Demise of Hurricane Barbara



NOAA's GOES-14 satellite captured Hurricane Barbara's landfall in southwestern Mexico and movement across land, northward toward the Gulf of Mexico. This 43 second animation of NOAA's GOES-14 satellite observations from May 29 to 31, 2013, shows Barbara making landfall at the beginning of the animation, and moving toward the Gulf of Mexico by May 31. Credit: NASA GOES Project



Hurricane Barbara recently made landfall along the southern Pacific coast of Mexico and NASA's TRMM and Suomi NPP satellites captured rainfall rates within the storm, and a night-time image of landfall. NOAA's GOES satellites provided images that were made into an animation showing the landfall and movement across Mexico into the Bay of Campeche on May 31.



According to the National Hurricane Center (NHC), the center of Hurricane Barbara came ashore around 19:50 UTC (12:50 p.m. PDT) on Wednesday, May 29 about 35 km (~20 miles) west of Tonala, Mexico. At landfall, Barbara was a minimal Category 1 hurricane with maximum sustained winds of 75 mph.







NASA-NOAA's Suomi NPP Satellite Captures Hurricane Barbara at Night



The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard the NASA-NOAA Suomi NPP satellite captured a nighttime image of Hurricane Barbara before it made landfall in southwestern Mexico. The image was taken on May 29 at 08:22 UTC (4:22 a.m. EDT). In the image city lights from Mexico City and Coatzacoalcos were seen to the north and east of Barbara's center.



VIIRS, a scanning radiometer, collects visible and infrared imagery and radiometric measurements of the land, atmosphere, cryosphere, and oceans.



NASA's TRMM Satellite Analyzes Barbara's Rainfall



NASA and the Japanese Space Agency's Tropical Rainfall Measuring Mission (TRMM) satellite captured several images of the storm during the landfall. TRMM captured the first image of Barbara several hours after it made landfall. The image was taken at 6:46 p.m. PDT on May 29 (01:46 UTC, May 30) and showed the horizontal distribution of rain intensity within the storm. The rainfall images were created at NASA's Goddard Space Flight Center in Greenbelt, Md. To make the image, several data products from various TRMM instruments are combined. 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). The rain rates are then overlaid on infrared (IR) data from the TRMM Visible Infrared Scanner (VIRS).



As is typical, after making landfall Barbara began to weaken and was a tropical storm with winds reported at 60 mph at the time of the first TRMM image. The image showed no evidence of an eye and areas of mostly light to moderate rain within the storm. Localized areas of heavier rain are evident inland northwest of the center and along the coast where the storm's circulation is drawing moist air ashore.



After making landfall, Barbara continued in a mostly northward direction across southern Mexico and began to emerge over the southern Gulf of Mexico.



The second rainfall image from TRMM was taken at 09:58 UTC (2:58 am PDT) on May 30. By that time, the National Hurricane Center had downgraded Barbara to a tropical depression with maximum sustained winds of 30 knots (~35 mph). Most of the rain associated with Barbara at that time appeared to be light with a smaller proportion of moderate rain than before and only an isolated area of heavy rain along the Gulf coast side.



TRMM data was used to create a 3-D image to look at precipitation and cloud heights. Most of the cloud tops were of low to moderate height with the exception of the one taller towering thunderstorm that reached up to around 12 km. This convective tower was associated with an area of heavy rain. In order for the storm to regenerate or maintain itself, new areas of convection like this would have to occur near the center.



GOES-14 Satellite Sees Barbara at the Gulf of Mexico



NOAA's GOES-14 satellite captured Hurricane Barbara's landfall in southwestern Mexico and movement across land, northward toward the Gulf of Mexico. In a 43 second animation of NOAA's GOES-14 satellite observations from May 29 to 31, 2013, Barbara made landfall at the beginning of the animation, and moved toward the Gulf of Mexico by May 31. The images from May 31, showed scattered showers were occurring over the Bay of Campeche and in the coastal city of Coatzacolalcos reported light rain. The animation was created by the NASA/NOAA GOES Project at NASA's Goddard Space Flight Center.



What Happened to Barbara?



On May 30 at 22:00 UTC (6:00 p.m. EDT), Barbara was a tropical depression with maximum sustained winds near 20 knots. It was centered about 127 nautical miles north-northeast of Tehuantepec, Mexico and was moving north at 4 knots.



By Friday, May 31 at 8:05 a.m. EDT, the National Hurricane Center (NHC) noted that a weak upper level trough (elongated area) of low pressure extended over the western Gulf of Mexico is steering the remnants of Barbara. Barbara's remnants had weakened further into a trough of low pressure at the surface and stretched from 19 north latitude and 94 west longitude to 22 north and 93 west.



NHC reported that the weak mid-level circulation associated with Barbara continues to gradually dissipate and become embedded within southeasterly flow over the western Gulf of Mexico.



The East Pacific hurricane season officially begins on May 15 and runs through November 30.



Text credit: Steve Lang / Rob Gutro

SSAI/NASA's Goddard Space Flight Center

May 30, 2013



NASA Sees Hurricane Barbara Quickly Weaken to a Depression



Tropical Storm Barbara strengthened into a hurricane just before it made landfall late on May 29, and after landfall it weakened into a tropical depression. NASA satellite imagery showed that cloud tops warmed and thunderstorms became more fragmented around the storm's center after Barbara made landfall.



Barbara is moving across the Isthmus of Tehuantepec today, May 30. Barbara could regenerate over the Bay of Campeche, on the Gulf of Mexico side of Mexico, and satellite imagery is watching Barbara closely. The Bay of Campeche is surrounded on three sides by the Mexican states of Campeche, Veracruz and Tabasco and is part of the Gulf of Mexico.



At 2 p.m. EDT on May 29, Barbara became a hurricane with maximum sustained winds near 75 mph. Just three hours later Barbara was already moving over land. It brought heavy rainfall to eastern Oaxaca and Western Chiapas, Mexico.



The MODIS instrument aboard NASA's Aqua satellite captured a visible image of Hurricane Barbara as it was making landfall in southwestern Mexico. The image was taken at 19:30 UTC (3:30 p.m. EDT). The image showed a large "tail" of thunderstorms that extended into the eastern Pacific Ocean.



By 8 p.m. EDT Barbara weakened back to tropical storm status as maximum sustained winds dropped to 60 mph. At 11 p.m. EDT, Barbara, still a tropical storm, although weaker was dropping a lot of rain. It was located near 17.1 north and 93.8 west, about 50 miles (85 km) west-northwest of Tuxtla Gutierrez, Mexico.



The Atmospheric Infrared Sounder (AIRS) instrument that flies aboard NASA's Aqua satellite captured infrared images of Barbara's cloud top temperatures on May 29 and May 30. The images showed that the interaction with landfall had a large toll on the organization and uplift of air within the storm. In an image from May 29 at 19:23 UTC (3:23 p.m. EDT) Barbara contained a large area of powerful thunderstorms, where cloud top temperatures were as cold as -63F (-52C). Those storms had the potential for heavy rainfall. After Barbara made landfall, AIRS captured another infrared image that showed how the friction of Barbara's land interaction drastically reduced the uplift and thunderstorm development as cloud top temperatures warmed. The AIRS image, taken on May 30 at 07:35 UTC (3:35 a.m. EDT) showed fragmented strong thunderstorms around the center of circulation, with the largest area over the Gulf of Campeche.



By 5 a.m. EDT on May 30, Barbara weakened to a tropical depression with maximum sustained winds near 35 mph (55 kph). It was centered near 17.8 north and 93.9 west, about 40 miles (60 km) southeast of Coatzacoalcos, Mexico. Barbara is moving to the north at 8 mph (13 kph) and has a minimum central pressure of 1000 millibars. At that time, there were no warnings or watches in effect.



Barbara continues to be a big rainmaker over land. The National Hurricane Center (NHC) expects Barbara to produce total rain accumulations of 6 to 10 inches with isolated maximum amounts of 20 inches possible over portions of southeastern Mexico. The NHC reports that Arriaga, located in the State of Chiapas recorded a rainfall total of 16.02 inches (407 mm) in 18 hours from 11 a.m. EDT on May 29 to 5 a.m. EDT, May 30.



The Independent.ie reported that two people were killed as a result of the storm. A 26 year old Mexican resident was killed in an attempt to cross a rain swelled river and a 61-year-old U.S. man who was surfing at a Salina Cruz beach drowned during the storm.



The National Hurricane Center expects Barbara to keep dropping large amounts of rain over portions of southeastern Mexico today, May 30 as it heads for the Bay of Campeche. Barbara is expected to drop between 6 and 10 inches of rainfall with isolated maximum amounts up to 20 inches today, so inland flooding and mudslides are possible.



Text credit: Rob Gutro

NASA's Goddard Space Flight Center

May 29, 2013



NASA Sees Tropical Storm Barbara Intensifying Before Landfall



Two NASA satellites revealed strength within Tropical Storm Barbara as it heads toward a landfall in southwestern Mexico on May 29. NASA's TRMM satellite data showed a powerful "hot tower" within Tropical Storm Barbara which is indicative of strengthening, and NASA's Aqua satellite confirmed strong thunderstorms surrounded Barbara's center.



The Tropical Rainfall Measuring Mission or TRMM satellite measures rainfall from space and is also used to calculate the heights of thunderstorms. When TRMM passed over Tropical Storm Barbara on May 28 at 11:50 UTC (7:50 a.m. EDT), it detected heaviest rainfall west of the center in a "hot tower."



A "hot tower" is a tall cumulonimbus cloud that reaches at least to the top of the troposphere, the lowest layer of the atmosphere. The troposphere extends approximately nine miles (14.5 km) high in the tropics. The hot tower in Barbara was about9.9 miles (16 km) high. The towers are called "hot" because they rise to such altitude due to the large amount of latent heat. Water vapor releases this latent heat as it condenses into liquid. NASA research shows that a tropical cyclone with a hot tower in its eyewall was twice as likely to intensify within six or more hours, than a tropical cyclone that lacked a hot tower.



The low pressure area formerly known as System 92E intensified into Tropical Storm Barbara on May 28 at 8 p.m. EDT.



By May 29 (today) at 11 a.m. EDT, Barbara's maximum sustained winds increased to 65 mph (100 kph). The National Hurricane Center forecasts Barbara to become a hurricane before landfall later today. Barbara's center was located near 15.7 north latitude and 94.6 west longitude, just 55 miles (85 km) southeast of Salina Cruz, Mexico. Barbara is moving to the northeast at 13 mph (20 kph) and is expected to move to the north-northeast, then north while slowing down.



The Atmospheric Infrared Sounder (AIRS) instrument that flies aboard NASA's Aqua satellite captured an infrared image of Tropical Storm Barbara's cloud top temperatures. AIRS data showed strong thunderstorms around the center of circulation with cloud top temperatures exceeding -63F (-52C). The image was captured on May 28 at 8:35 UTC (4:35 a.m. EDT). The National Hurricane Center noted that radar imagery at 11 a.m. EDT on May 29 suggested a banding-type eye as opposed to a closed eyewall.



A Hurricane Warning is in effect from Puerto Angel to Barra De Tonala, Mexico. A Tropical Storm Warning is in effect from Barra De Tonala to Boca De Pijijiapan, Mexico.



Barbara is expected to drop rainfall totals between 4 and 8 inches over eastern Oaxaca and western Chiapas provinces, with up to 12 inches to the southeast of Oaxaca. This could trigger life-threatening flashfloods and mudslides. Hurricane wind conditions are expected in the warning area later in the day on May 29, and a storm surge could raise water levels by 3 to 5 feet above normal tide levels along the immediate coast near and to the east of where the center makes landfall, according to the National Hurricane Center.



The center of Barbara will cross the coast in the hurricane warning area later today...and move over southeastern Mexico tonight and Thursday where it will dissipate within a day or two.



For an animated radar image of rainfall from Tropical Storm Barbara showing the center of circulation near Puerto Angel on May 29 from 07:30 UTX to 12:30 UTC (3:30 a.m. to 8:30 a.m. EDT) click here: http://andrew.rsmas.miami.edu/bmcnoldy/tropics/barbara13/Barbara_29-30May13_ange.gif. Credit: Brian McNoldy, RSMAS/Univ of Miami



Text credit: Rob Gutro

NASA's Goddard Space Flight Center

May 28, 2013



NASA Sees Developing Tropical Cyclone Near Southwestern Mexico



NASA's Aqua satellite captured an image of System 92E, a tropical low pressure area that is ripe for development into a tropical depression and tropical storm, as it continues to develop near to southwestern Mexico.



System 92E may organize more and become Tropical Storm Barbara later on May 28 as it continues organizing near the southwestern Mexican coast. When NASA's Aqua satellite flew over System 92E on May 28 at 07:17 UTC (3:17 a.m. EDT), the Atmospheric Infrared Sounder (AIRS) instrument aboard Aqua captured an infrared image of the storm. AIRS measured cloud top temperatures as cold as -63 Fahrenheit (-52 Celsius), that were indicative of high, strong thunderstorms with the potential to drop heavy rain. Those storms stretched over open waters west of Punta Escondida southward to Salina Cruz.



System 92E appears almost stationary, and the National Hurricane Center (NHC) expects the low to continue consolidating. Shower and thunderstorm activity continues to gradually increase today, May 28. System 92E's center is about 200 miles south of Salina Cruz, Mexico.



The NHC expects System 92E to become Tropical Storm Barbara late in the day on May 28, before it makes landfall later along the southwestern coast of Mexico. Tropical Storm Warnings could be posted later in the day and heavy rains are expected over southern Mexico and western Central America during the next few days.



Text credit: Rob Gutro

NASA's Goddard Space Flight Center