[image-236][image-252]TRMM Eyes Rainfall in Dissipating Former Hurricane Cristina
NASA and the Japan Aerospace Exploration Agency's Tropical Rainfall Measuring Mission or TRMM satellite passed over a dissipating former Hurricane Cristina and found it still contained heavy rain as it rapidly weakened.
Hurricane Cristina had sustained winds of over 130 knots (almost 150 mph) on June 12, 2014 making her the second hurricane in the eastern Pacific Ocean this year to reach category four on the Saffir-Simpson hurricane wind scale.
The TRMM satellite had an excellent view of Cristina when it flew over on June 14, 2014 at 1031 UTC (6:31 a.m. EDT). At that time, Cristina had started weakening and had wind speeds estimated at less than 70 knots (about 80 mph) when TRMM flew overhead. To form a complete picture of the storm, rainfall from TRMM's Microwave Imager (TMI) and Precipitation Radar (PR) instruments were overlaid on an enhanced infrared image of Cristina's clouds taken from NOAA's GOES-West satellite. The images were combined at NASA's Goddard Space Flight Center in Greenbelt, Maryland.
Although Cristina had started a weakening trend TRMM's Precipitation Radar instrument still found rain falling at a rate of almost 97 mm (about 3.8 inches) per hour in the northwestern side of Cristina's eye wall. At Goddard, TRMM's PR data was used to create a 3-D view of the Cristina's rainfall structure. That 3-D image showed powerful thunderstorms in the northwestern side of the storm were reaching heights above 13.5 km (about 8.4 miles). These same TRMM data showed that Cristina's eye wall was broken on the eastern side.
The passage of Cristina over cooler ocean waters and southwesterly wind shear resulted in the once powerful hurricane dissipating to a remnant low pressure area on Sunday, June 15, 2014.
On June 17 at 09:02 a.m. EDT, the National Hurricane Center (NHC) noted that the remnant low pressure center of Cristina continued to spin in the Eastern Pacific, and the circulation center was located near 23 north latitude and 117 west longitude. NHC forecasters noted that the circulation will continue to spin down over the next couple of days and is expected to dissipate by the night time hours on Wednesday, June 18.
Text credit: Hal Pierce
SSAI/NASA's Goddard Space Flight Center
[image-216][image-230]A Satellite View: Former Hurricane Cristina Now a Ghost of Its Former Self
An infrared image from NOAA's GOES-West satellite showed what appeared to be a ghostly ring of clouds and no convection in former Hurricane Cristina on Monday, June 16 as the system weakened to a remnant low pressure area.
Convection is rising air that forms the thunderstorms that make up a tropical cyclone and when there is none, there are no thunderstorms to keep it going. That's exactly what happened to Cristina in the Eastern Pacific Ocean on Sunday, June 15.
At 11 a.m. EDT (8 a.m. PDT) on Sunday, June 15, Cristina had weakened to a tropical depression near latitude 20.1 north and longitude 113.3 west, about 290 miles (470 km) southwest of the southern tip of Baja California At that time the depression was moving toward the west-northwest near 6 mph (9 kph) and Cristina's maximum sustained winds had decreased to near 35 mph (55 kph).Forecaster Brennan at the National Hurricane Center (NHC) noted that "Cristina continues to lack any deep convection, which is not surprising given the hostile environment of strong shear, cool waters and dry air."
That hostile environment took its toll on Cristina early on June 16 when the NHC declared Cristina a remnant low pressure area. At 09:07 UTC (5:07 a.m. EDT), the post-tropical remnant low pressure area formerly known as Cristina was centered near 21 north latitude and 115 west longitude. The remnant low had maximum sustained winds near 20 to 25 knots (23 to ~29 mph/37 to ~46 kph) and was generating seas to 8 feet (2.4 meters). As Cristina's remnants continue to dissipate, NHC forecasters expect wave heights to decrease.
Text credit: Rob Gutro
NASA's Goddard Space Flight Center
[image-204][image-188]NASA Sees Hurricane Cristina Making a Reverse in Strength
Hurricane Cristina intensified rapidly on June 12 and infrared satellite data showed cloud top temperatures became extremely cold as thunderstorms towered to the top of the troposphere. One day later, Cristina was weakening quickly and infrared data showed cloud top temperatures were warming as the cloud tops dropped.
Infrared data basically reads a cloud top's temperature. When NASA's Aqua satellite passed over Hurricane Cristina early on June 12, cloud top temperatures exceeded -80C (-112F). Today, June 13, infrared data showed cloud top temperatures had warmed to near -53C (-63F) over a large area of the storm as cloud heights dropped. Cloud heights dropped because the convection had weakened.
Basically, convection occurs when a parcel of air near the Earth’s surface is heated, it rises (making it lighter than the surrounding air). As convection continues the air pressure begins to fall, and the parcel of air expands. When that happens, the air consumes heat energy and temperature in the parcel falls. When the parcel of air cools enough and reaches the dew point, clouds form (condensation occurs). If the air is unstable, that convection will continue at much higher levels in the atmosphere and it can create towering thunderstorms.
The National Hurricane Center discussion on June 13 at 5 a.m. EDT noted that Cristina had weakened almost as fast as it intensified the day before. Microwave imagery suggested that the eyewall is about 50 percent open, and only occasional hints of an eye can be seen on conventional satellite data.
On June 13 at 11 a.m. EDT (1500 UTC) Cristina's center was located near latitude 18.0 north and longitude 109.6 west about 105 miles (170 km) east-southeast of Socorro Island, Mexico. Cristina was moving toward the northwest near 8 mph (13 kph) and is expected to continue in that direction over the next day before turning west-northwestward later in the weekend (June 14 and 15). Cristina's maximum sustained winds have decreased to near 100 mph (155 kph). According to forecaster Berg at the NHC, Cristina is expected to become a tropical storm on Saturday, June 14.
In a visible image of Hurricane Cristina taken from NOAA's GOES-West satellite at 11 a.m. EDT on June 13, the eye was no longer visible.
Cristina is now in a weakening trend. The NHC noted that cooling sea surface temperatures (cooler than 26C/80F) in addition to increasing shear and dry air aloft will continue to weaken Cristina to a remnant low pressure area in three or four days.
Text credit: Rob Gutro
NASA's Goddard Space Flight Center
[image-36][image-140][image-156]June 12, 2014 - NASA and NOAA Satellites Analyze Category 4 Hurricane Cristina
A fleet of satellites from NASA and NOAA are on the job monitoring the second major hurricane of the Eastern Pacific Ocean Season as Hurricane Cristina has reached Category 4 status on the Saffir-Simpson scale. Back on May 25, Amanda strengthened into the first Major Hurricane in the Eastern Pacific Ocean with maximum sustained winds near 155 mph (250 kph).
This morning, June 12, at 1200 UTC (8 a.m. EDT), NOAA's GOES-West satellite provided an infrared image of Hurricane Cristina that showed a very clear, distinct eye. Although Cristina's center is over open ocean, this intense hurricane is causing rough surf along the west coast of Mexico today. The National Hurricane Center (NHC) noted that swells continue to affect southwestern Mexico, and could cause life-threatening surf and riptide conditions.
NHC noted in the discussion at 11 a.m. EDT (8 a.m. PDT) that Cristina has gone through an extraordinary, but not unprecedented, phase of rapid intensification during the past 24 hours, with its maximum winds increasing by about 65 knots (74.8 mph/120.4 kph) since that time on June 11.
When the TRMM satellite flew over Cristina on June 11, 2014 at 1142 UTC (4:42 a.m. PDT) it was a hurricane. A rainfall analysis that used data from TRMM's Microwave Imager (TMI) and Precipitation Radar (PR) instruments was overlaid on an enhanced infrared image received by NOAA's GOES-East satellite at 1145 UTC (7:45 a.m. EDT) to provide a complete picture of the hurricane's cloud extent and rainfall rates. The TRMM TMI data clearly revealed that an eye had developed indicating that Cristina was definitely a hurricane. TRMM PR found that rain was falling at a rate of over 74.4 mm (2.9 inches) per hour in a strong feeder band east if Cristina's eye. Another smaller area of strong convective thunderstorms west of Puerto Vallarta, Mexico was also found to contain very heavy rainfall with the tallest thunderstorm tops reaching heights of about 16.5km (10.2 miles).
Later on June 11, at 19:59 UTC (3:59 p.m. EDT) when NASA's Aqua satellite passed over Hurricane Christina as it was rapidly intensifying, the Atmospheric Infrared Sounder (AIRS) instrument gathered infrared data on the cloud top temperatures of the storm. By early morning on June 12, Cristina had a circular central dense overcast with very cold cloud tops near -80C (-112F).
At 11 a.m. EDT (8 a.m. PDT) on June 12, Hurricane Cristina's maximum sustained wind were near 150 mph (240 kph). Cristina was about 250 miles (400 km) southwest of Manzanillo, Mexico, near latitude 16.6 north and longitude 107.1 west. Cristina was moving toward the west-northwest near 8 mph (13 kph) and a northwestward to west-northwestward motion is expected through Saturday morning (June 14).The estimated minimum central pressure is 935 millibars.
The NHC said that light vertical wind shear and a deep warm ocean should allow Cristina to maintain major hurricane strength for another 36 hours.
Text credit: Rob Gutro
NASA's Goddard Space Flight Center
[image-78][image-94][image-110]June 11, 2014 - Cristina Now a Hurricane, NASA's TRMM Satellite Sees Heavy Rainfall Within
Before Tropical Storm Cristina intensified into a hurricane, NASA's TRMM satellite passed overhead and gathered data that showed areas of heavy rainfall were occurring within.
The National Hurricane Center (NHC) upgraded the third tropical depression of the Eastern Pacific Ocean to tropical storm status and named it Cristina on June 10 at 0300 UTC (8 p.m. PDT). Earlier that morning at 1238 UTC (5:38 a.m. PDT), the Tropical Rainfall Measuring Mission (TRMM) satellite flew over the depression and gathered rainfall data that hinted that the storm was intensifying. At NASA's Goddard Space Flight Center in Greenbelt, Maryland, rainfall from TRMM's Microwave Imager (TMI) and Precipitation Radar (PR) were overlaid on an enhanced visible/infrared 1245 UTC (8:45 a.m. EDT) image from the GOES-East satellite to provide a view of clouds and rainfall within the storm. The TRMM TMI data showed large areas of moderate to heavy rainfall occurring west of Mexico's coast. TRMM data also showed a closed low- to mid-level ring of thunderstorms surrounding Cristina's center.
On June 11, NHC Forecaster Kimberlain noted that Cristina continues to intensify. The cyclone consists of a small central dense overcast in geostationary satellite imagery. Infrared imagery, such as that from the Atmospheric Infrared Sounder instrument aboard NASA's Aqua satellite, showed that cloud top temperatures in powerful thunderstorms in the northern semicircle of the storm are as cold as -80C (-112F). Cloud top temperatures that cold indicate strong storms with the potential to drop heavy rainfall, which complemented the data seen by the TRMM satellite on June 10. Kimberlain also noted that there were faint hints of eye or warm spot during the early morning hours of June 11.
At 5 a.m. EDT (2 a.m. PDT), Hurricane Cristina had maximum sustained winds near 75 mph (120 kph). Cristina was centered near 15.2 north latitude and 104.1 west longitude, about 265 miles (425 km) south of Manzanillo, Mexico. Cristina is moving west at 6 mph (9 kph) and is expected to turn to the west-northwest over the next couple of days, according to NHC. Minimum central pressure was 990 millibars
NOAA's GOES-West satellite captured an infrared view of Hurricane Cristina on June 11 at 1200 UTC/8 a.m. EDT off the west coast of Mexico. The image did not yet show an eye, but the NHC expects Cristina to continue strengthening so future satellite imagery may catch that eye "opening."
Although Cristina is not over land, it is close enough to cause dangerous ocean swells that are affecting portions of the south-central and southwestern coast of Mexico. NHC noted that these swells will likely continue into Wednesday, June 11, and could cause life-threatening surf and rip current conditions.
The NHC noted that the environment in which Cristina is embedded remains ideal for further intensification.
Text credit: Harold F. Pierce / Rob Gutro
SSAI/NASA's Goddard Space Flight Center
[image-51]June 10, 2014 - NASA Sees Tropical Storm Christina's Birth and Severe Weather in U.S. South
NASA's Aqua satellite captured a picture of newborn Tropical Storm Cristina on June 10, marking the birth date of the Eastern Pacific Ocean's third tropical storm of the season. The same image showed the severe weather affecting the south central U.S.
Although not at the coastline, the National Hurricane Center said that Cristina is near enough to cause dangerous surf conditions.
According to the National Hurricane Center (NHC), swells generated by Cristina are affecting portions of the south-central coast of western Mexico. These swells will likely continue through today, June 10, and could cause life-threatening surf and rip current conditions.
Early in the morning of June 9, forecasters at the NHC were watching a fast-developing tropical low pressure area designated as System 94E. By 5 p.m. EDT the Eastern Pacific Ocean had a new tropical depression. Tropical depression 03E was born near 15.4 north latitude and 102.0 west longitude, about 160 miles (260 km) south of Zihuatanejo, Mexico. Maximum sustained winds were near 35 mph (55 kph).
Since then, Tropical Depression 3E strengthened and by June 10, it became a tropical storm and was renamed "Cristina."
At 08:23 UTC (4:23 a.m. EDT) when NASA's Aqua satellite passed over Cristina, the Atmospheric Infrared Sounder (AIRS) captured an infrared of the storm. The infrared image was false-colored to better identify temperature of cloud tops. Higher, colder cloud tops indicate strongest storms, and those were seen wrapping sound of the center of circulation, and in a large band to the north, over coastal Mexico. Cloud top temperatures in those bands exceeded -63F (-53C), indicating they were near the top of the troposphere. NASA research showed that thunderstorms that high in the atmosphere have the capability to produce heavy rainfall.
The AIRS image also showed strong to severe thunderstorms associated with an area of low pressure in eastern Texas. A band of strong thunderstorms with very cold, high cloud tops stretched from southeastern Texas north into Arkansas.
By 11 a.m. EDT (1500 UTC) the center of Tropical Storm Cristina was located near latitude 15.5 north latitude and 102.9 west longitude. The National Hurricane Center reported that Cristina's maximum sustained winds were near 45 mph (75 kph). Cristina is moving toward the west near 5 mph (7 kph) and is expected to continue in that direction, away from the Mexico coastline. The estimated minimum central pressure is 1003 millibars.
The NHC forecast calls for additional strengthening over the next day or two and Cristina could become a hurricane by Thursday, June 12.
Text credit: Rob Gutro
NASA's Goddard Space Flight Center
