NASA Saw Henriette Fading and Two Struggling Lows Behind [image-186]
Once a hurricane, Henriette weakened to a depression in the Central Pacific Ocean on Sunday, Aug. 11 and dissipated by Aug. 12 as two other low pressure areas continued to struggle. NASA's TRMM satellite noticed that Henriette's weakening trend began on Aug. 8.
NASA's Tropical Rainfall Measuring Mission or TRMM satellite flew over Henriette again on August 9, 2013 at 0122 UTC (~ 4 p.m. local time). During a TRMM orbit overpass on August 8, 2013 at 1709 UTC. (1:09 a.m. EDT), Henriette's eye that was visible but disappeared from view on Aug. 9.
At NASA's Goddard Space Flight Center in Greenbelt, Md. 3-D images were created showing TRMM data on Aug. 6 and Aug. 9 using Precipitation Radar (PR) data. On Aug. 6 rain was falling at a rate of over 161mm (~6.3 inches) per hour near the center of the hurricane and the tremendous amount of energy being released by towering thunderstorms in Henriette's forming eye was evident with tops reaching almost 16.75 km (~10.41 miles). In contrast, TRMM PR data from Aug. 9 showed thunderstorms near Henriette's center were found to reach heights of less than 12 km (~7.5 miles) indicating the storm had weakened. Henriette dissipated south of Hawaii early on Aug. 12.[image-202]
On Monday, Aug. 12, two areas of low pressure are being watched for possible development in the Eastern Pacific Ocean. They are located east of where Henriette dissipated are referred to as System 93E and System 92E.
The elongated area of low pressure or trough called System 93E is about 1,300 miles east-southeast of Hawaii near 13 north and 136 west. It is producing disorganized showers and thunderstorms and it is moving westward at 10 to 15 mph. This system has a low chance, just 10 percent, of becoming a tropical cyclone during the next two days.
Farthest east is low pressure System 92E, near 13.2north and 123.6 west, about 1,125 miles southwest of Cabo San Lucas, Mexico. That low is also producing disorganized showers and thunderstorms, but has a slightly better chance of developing first. The National Hurricane Center gives System 92E a 20 percent chance for becoming a tropical depression in the next 2 days.
Text credit: Hal Pierce/Rob Gutro
SSAI/NASA's Goddard Space Flight Center
August 09, 2013 - NASA Paints a Panorama of Pacific Tropical Cyclones[image-170]
The Central and Eastern Pacific Oceans continue to be active on Aug. 9, as Hurricane Henriette weakens and two other low pressure systems continue developing. All three systems were captured on the one panoramic satellite image.
An image from NOAA's GOES-West satellite on Aug. 9 at 1200 UTC (8 a.m. EDT) captured all three tropical systems. The storm farthest west is Hurricane Henriette, followed by System 92E to the east. System 92E is trailed by System 93E even further east. The GOES-West imagery shows that System 92E has a more developed circulation, and the National Hurricane Center gives that low pressure area a much higher chance to develop in the next couple of days than System 93E.The GOES-West image was created at NASA's GOES Project at NASA's Goddard Space Flight Center in Greenbelt, Md.
Henriette Losing its Punch
On Aug. 9 at 1500 UTC (11 a.m. EDT), Hurricane Henriette has been weakening and maximum sustained winds have dropped to 75 mph/120 kph. Henriette was centered near 16.4 north and 141.4 west, about 930 miles/1,495 km east-southeast of Hilo, Hawaii. Henriette was moving to the west-southwest at 14 mph/22 kph and had a minimum central pressure of 992 millibars.
GOES-West imagery showed that Henriette has become more asymmetric, a sign of weakening. Tropical cyclones need to be circular in shape to maintain strength or strengthen. When they begin losing the circular shape, they start to "spin down" and slow down like a tire going flat. Infrared satellite data showed that the thunderstorm cloud top temperatures on the southern side of the storm were warming, indicating cloud heights were dropping. Warmer cloud top temperatures indicate lower storms, which means that they don't have as much uplift or strength in them as they did before.
The Central Pacific Hurricane Center noted that Henriette is expected to weaken to tropical storm force later on Aug. 9 and dissipate by Monday, Aug. 12.
System 93E a Slow-Developing Storm
System 93E is not developing as fast as its "sister" low pressure area, System 92E that trails to the east. GOES-West satellite imagery shows that this elongated area of low pressure (trough) is producing disorganized showers and thunderstorms. It is centered about 1,600 miles southwest of the southern tip of Baja California, Mexico. The National Hurricane Center noted that conditions are expected to be marginally conducive for gradual development of this system during the next few days, so the system has a low chance, about 20 percent, of becoming a tropical cyclone during the next two days.
System 92E on a Faster Tropical Track
System 92E is unlike its sister, 93E, and appears to be developing faster. Showers and thunderstorms associated with low pressure System 92E appear much more organized on the GOES-West satellite data. The low is centered about 800 miles southwest of Manzanillo, Mexico, near 10.6 north and 111.4 west. It is moving to the west at 10 to 15 mph. The National Hurricane Center gives System 92E a medium chance, about 50 percent, of becoming a tropical cyclone during the next two days.
Text credit: Rob Gutro
NASA's Goddard Space Flight Center
Hurricane Henriette Leading a Westbound Train of Developing Storms[image-154]
Satellite imagery on Aug. 8 shows Hurricane Henriette leading a westward bound train of developing tropical cyclones in the Eastern Pacific. NOAA's GOES-West satellite captured an image of Henriette and two low pressure areas behind it.
NOAA's GOES-West or GOES-15 satellite keeps a constant vigil over the western U.S. and the Eastern Pacific Ocean. In a GOES-West image on Aug. 8 at 1200 UTC (8 a.m. EDT), a well-developed Hurricane Henriette was crossing into the Central Pacific Ocean, while a new and un-named low pressure area trailed hundreds of miles to the east. Farther east from that low was System 92E. Of those two low pressure areas, System 92E has the higher chance of organizing into a tropical storm first.
The New Low Pressure Area
The next system on the "train of storms" is the un-named low between System 92E and Henriette. It is actually an elongated area of low pressure (a trough). That low is about 1,500 miles southwest of the southernmost tip of Baja California, Mexico. The trough does appear somewhat elongated on the GOES-West satellite image.
The NHC gives that low a near zero chance of developing in the next two days, but that chance goes up to 20 percent in five days.
System 92E Shows Some Promise
Following up in the caboose of tropical systems is System 92E. On Aug. 8, System 92E was located near 11.4 north and 102.0 west, about 650 miles southwest of Manzanillo, Mexico. System 92E appears to have circulation on the GOES-West satellite imagery.
The National Hurricane Center or NHC gives System 92E a 40 percent chance of development in the next two days and a 70 percent chance in five days. System 92E is producing disorganized showers and thunderstorms and is moving to the west at 10 mph.
Hurricane Henriette the Engine
Hurricane Henriette is the farthest west of the three tropical systems, and is the engine of the tropical train.
Henriette was a Category 2 hurricane on the Saffir-Simpson Scale at 11 a.m. EDT on Aug. 8, with maximum sustained winds near 100 mph/160 kph, and a weakening trend is forecast to begin today, Aug. 8.
Hurricane Henriette's eye was visible in the GOES-West satellite image and the storm has the hurricane shape with an "arm" or band of thunderstorms wrapping around from the south of the center. Enhanced infrared satellite imagery showed an eye under compact dense overcast, where cloud top temperatures were near -50C/-58F.
Henriette's center was located near latitude 17.2 north and longitude 138.4 west, about about 1,110 miles/1,785 km east of Hilo, Hawaii. Henriette is moving toward the west near 10 mph/17 kph and is expected to continue in a westward to west-southwestward motion. The estimated minimum central pressure is 980 millibars.
Later on Aug. 8, Henriette is expected to track nto the Central Pacific Ocean, which begins near 140 degrees west longitude. Once Henriette crosses that line, NOAA's Central Pacific Hurricane Center will be issuing forecasts for the storm.
Text credit: Rob Gutro
NASA's Goddard Space Flight Center
August 07, 2013 - NASA Sees 10-mile High Thunderstorms in Hurricane Henriette[image-110]
NASA's TRMM satellite peered into the clouds of Hurricane Henriette as is continues moving through the Eastern Pacific Ocean, and found powerful thunderstorms that topped 10 miles high.
The higher the thunderstorms are, the more powerful the uplift in the air, and more powerful the thunderstorms. Thunderstorms that reach 10 miles high, like some of the ones seen in Hurricane Henriette tend to drop heavy rainfall, and NASA's Tropical Rainfall Measuring Mission or TRMM satellite confirmed that.
The TRMM satellite flew over the eastern Pacific Ocean on August 6, 2013 at 0233 UTC (~5:33 p.m. Hawaii local time) collecting data for low sun angle views of Hurricane Henriette. A visible/infrared image created by TRMM data showed shadows cast by towering thunderstorms on the northeastern side of Henriette's eye wall.[image-126]
TRMM is able to measure rainfall occurring in a storm from its orbit in space. Rainfall is derived from TRMM's Microwave Imager and Precipitation Radar instruments. TRMM's PR instrument measured rain falling at the rate of over 55.46 mm (~2.2 inches) per hour a towering thunderstorm near Henriette's center.
At NASA's Goddard Space Flight Center in Greenbelt, Md. the TRMM team used the satellite's data to create 3-D images and animations. One 3-D image looking toward the east from TRMM PR data revealed that towering storms in the northeastern side of Henriette's eye were reaching heights of almost 16.75km (~10.41 miles). This kind of chimney cloud, also called a "hot tower" (as it releases a huge quantity of latent heat by condensation) can play a part in the formation or intensification of tropical cyclones. Intense rainfall in Henriette's eye wall was returning values greater than 48.7dBZ to the TRMM satellite.
At 11 a.m. EDT on Aug. 7, Hurricane Henriette's maximum sustained winds were near 85 mph/140 kph, and little change in strength is expected today, while weakening is expected to begin tomorrow, Aug. 8. The center of Hurricane Henriette was located near latitude 16.2 north and longitude 134.9 west, about 1,350 miles/2,170 km east of Hilo, Hawaii. Henriette is moving toward the west-northwest near 10 mph/17 kph and is expected to continue in that direction before turning west tomorrow, Aug. 8. [image-140]
Text credit: Hal Pierce / Rob Gutro
SSAI / NASA's Goddard Space Flight Center
August 06, 2013 - NASA Sees Henriette Still a Hurricane[image-94]
Tropical Depression Gil regained strength after moving into warmer waters and an area with lighter wind shear as Hurricane Henriette hangs on. NASA's Aqua satellite captured an infrared look at both storms showing powerful thunderstorms around each of their centers of circulation.
The Atmospheric Infrared Sounder or AIRS instrument aboard NASA's Aqua satellite captured infrared data on both Gil and Henriette on Aug. 6 at 10:39 UTC (6:39 a.m. EDT). At that time both Tropical Storm Gil and Hurricane Henriette had large areas of strong thunderstorms with very cold cloud tops around their centers. The cloud top temperatures in both storms were colder than -63F/-52C, which indicates thunderstorms high into the troposphere. Thunderstorms that high are also indicative of moderate to heavy rainfall.
Henriette the Hurricane
On Aug. 6 at 1500 UTC/11 a.m. EDT, Hurricane Henriette had maximum sustained winds near 80 mph/130 kph. Forecasters at the National Hurricane Center expect additional strengthening as Henriette continues to trail Tropical Storm Gil on a westward trek.
Henriette was centered about 1,605 miles/2,580 km east of Hilo, Hawaii, near 14.2 north latitude and 131.5 west longitude. Henriette was moving to the northwest near 10 mph/17 kph and is expected to fluctuate between a west-northwest and northwesterly direction over the next several days. The estimated minimum central pressure is 986 millibars. In two days, the Henriette is expected to move into slightly cooler waters and a drier, more stable airmass which is expected to weaken the storm.
In microwave satellite imagery today, Aug. 6, data revealed a well-defined eye in Henriette. In fact, the eye has even been spotted on GOES-15 visible imagery.
Text credit: Rob Gutro
NASA's Goddard Space Flight Center
August 05, 2013 - NASA Eyes Two Eastern Pacific Tropical Cyclones: One Up, One Down[image-51][image-78]
Tropical Depression Gil has been weakening for a couple of days, while Tropical Storm Henrietta appears to be strengthening in the Eastern Pacific Ocean. NOAA's GOES-15 satellite captured both storms in one image that clearly showed Henrietta was the larger storm, and NASA's Aqua satellite peered under Henrietta's clouds to reveal a developing eye.
Tropical Depression Gil is more than halfway to Hawaii from Mexico and continues to hold onto depression strength. Meanwhile, NOAA's GOES-15 satellite captured both storms in one image on Aug. 5 at 1200 UTC (8 a.m. EDT). The imagery shows Tropical Storm Henriette dwarfed the smaller Gil. The infrared image was created by NASA's GOES Project at NASA's Goddard Space Flight Center in Greenbelt, Md. GOES satellite imagery showed a circular concentration of thunderstorms tightly around Gil's small center, while Henriette, located to the east, is several times the size of Gil.
NASA Infrared Data Shows a Developing Eye in Henriette
Infrared data from the Atmospheric Infrared Sounder or AIRS instrument that flies aboard NASA's Aqua satellite showed a developing eye in Tropical Storm Henriette. AIRS captured an infrared image of Tropical Storm Henriette on August 5 at 0917 UTC (5:17 a.m. EDT). Strongest storms and heaviest rains appeared around the center where cloud top temperatures exceeded -63F/-52C. The GOES satellite imagery showed that Henriette had grown in size and dwarfs Tropical Depression Gil, located to its west.
Henriette developed from the System 90E which became the eighth tropical depression of the eastern Pacific Ocean hurricane season over the weekend of Aug. 3 and 4.
On Aug. 5 at 11 a.m. EDT (1500 UTC), Tropical Storm Henriette's maximum sustained winds had increased to near 60 mph/95 kph. Further strengthening is forecast by the National Hurricane Center and Henriette is expected to become a hurricane in the next day.
Henriette was located near latitude 12.1 north and longitude 128.2 west, about 1,415 miles (2,280 km west-southwest of the southern tip of Baja California, Mexico. Henriette is moving toward the west near 6 mph/9 kph and is expected to turn west-northwestward Minimum central pressure is near 999 millibars
NASA's Goddard Space Flight Center, Greenbelt, Md.