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Hurricane Season 2011: Hurricane Irwin (Eastern Pacific Ocean)
10.17.11
 
AIRS infrared image of Tropical Storm Irwin taken on Oct. 14 at 5 p.m. EDT. › View larger image
This infrared image of Tropical Storm Irwin was taken on Oct. 14 at 5 p.m. EDT from the AIRS instrument on NASA's Aqua satellite. The infrared data showed that Irwin's clouds were warming and the storm was weakening.
Credit: NASA/JPL, Ed Olsen
NASA Satellite Saw Tropical Depression Irwin's Last Breaths

NASA's Aqua satellite saw the hot breath come out of Tropical Depression Irwin weekend as cloud tops warmed on infrared imagery and convection waned.

When NASA's Aqua satellite flew over Tropical Storm Irwin on Oct. 14 at 5 p.m. EDT, the Atmospheric Infrared Sounder (AIRS) instrument captured an infrared look at the storm. At that time it was 185 miles west-southwest of Manzanillo, Mexico and it had maximum sustained winds of 40 knots (46 mph).

The infrared imagery from NASA showed that Irwin's clouds were warming, indicating that the strength of uplift within the storm was weakening. Irwin's strongest storms appeared on AIRS infrared imagery around its center, but the area of strong storms disappeared by Sunday, Oct. 16. Cloud top temperatures were colder than -63F (-52C) in that area, indicating strong thunderstorms and heavy rainfall.

Cloud tops warmed significantly on Sunday, and the National Hurricane Center issued its final advisory on Irwin. At 11 p.m. EDT on Oct. 16, Irwin's maximum sustained winds were near 25 knots (29 mph/46 kmh). It was centered near 14.1 North and 108.3 West, moving northwest at 4 knots (5 mph). Irwin has since dissipated.

Elsewhere in the eastern Pacific today, no tropical cyclones are expected.

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



October 14, 2011

satellite image of storms in Northwestern Hemisphere › Larger image
› Larger image (unlabeled)This NOAA GOES-11 satellite image of the eastern Pacific and Atlantic Oceans provides a good look at Tropical Storm Irwin (left) and all of the remnants and possible developing tropical cyclones in both ocean basins today, Oct. 14, 2011 at 7:45 a.m. EDT. The other systems include Low#1 off of Central America, remnants of Tropical Depression 12E now in the western Caribbean Sea, and System 94L west of Bermuda.
Credit: NASA/NOAA GOES Project
Tropical Storm Irwin is the Sole Survivor Among the Tropical "Ruins"

Satellite data today, October 14, 2011, shows that only Tropical Storm Irwin survives today and is now headed back to open waters in the Eastern Pacific. Irwin is the sole survivor of a tropical onslaught from earlier this week when Hurricane Jova and Tropical Depression 12E made landfall in Mexico. 12E's remnants are now trying to re-assemble in the Caribbean Sea.

NOAA's GOES-11 satellite captured an image that includes the eastern Pacific and Atlantic Oceans and shows Tropical Storm Irwin and all of the remnants and possible developing tropical cyclones in both ocean basins today, Oct. 14, 2011 at 7:45 a.m. EDT. The image was created at the NASA Goddard Space Flight Center in Greenbelt, Md. by the NASA/NOAA GOES Project. In the image, Irwin appears as a rounded area of clouds south of the Baja California, Mexico.

At 11 a.m. EDT on Oct. 14, Irwin had weakened again. Maximum sustained winds were near 40 mph (65 kmh). It was located about 165 miles (265 km) west of Manzanillo, Mexico, near 18.6 North and 106.8 West. It was moving slowly to the south at 3 mph (6 kmh) and is expected speed up and move to the south-southwest this weekend.

Infrared satellite imagery shows that the convection (rising air that forms the thunderstorms that make up Irwin) appears to be shapeless. Infrared data from the Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite showed cloud top temperatures have warmed, indicating they're falling. That means there's less energy/uplift in the storm, and it's weakening.

Irwin is dealing with two factors that are sapping its strength: winds and cooler waters. Specifically, increased wind shear, and the cold water stirred up from the ocean bottom from the earlier passage of Hurricane Jova. When water temperatures fall below 80 Fahrenheit (26.6 Celsius), a tropical cyclone starts weakening, because there's not as much evaporation and convection happening to support it. The National Hurricane Center expects Irwin to weaken into remnant low by early next week.

Another developing low, "Low #1" for reference is officially not yet numbered, formed offshore from Central America. Low #1 appears disorganized in the GOES-11 image as an elongated area of clouds. It is, in fact, an elongated area of low pressure (called a trough), and its off the coast of southern Mexico, Guatemala and El Salvador. Those clouds are producing showers and thunderstorms. Because the National Hurricane Center expects little movement over the weekend, those areas should expect locally heavy rainfall and flooding. Low #1 has a 10% chance of development over the weekend of Oct. 15-16.

Moving into the Atlantic Ocean basin is the remnants of Tropical Depression 12E (TD12E). They're centered near 17 North and 85 West. TD12E made landfall from the eastern Pacific and crossed over into the western Caribbean Sea. It is also a trough, and stretches from Central America, over the northwestern Caribbean Sea to Cuba. TD12E's remnants are producing disorganized showers and thunderstorms and conditions will allow for slow development. There's a 20% chance this low will become a tropical depression over the weekend.

Further east in the Atlantic is System 94L. It is centered near 28.0 North and 72.4 West about 350 miles west of Bermuda. Like the remnants of TD12E, it also has a 20% chance of development this weekend. During the morning of Oct. 14 showers and thunderstorms became a little more concentrated, according to the National Hurricane Center. Don't expect too much for System 94L, though. Upper-level winds are becoming more hostile and System 94L is expected to merge with the cold front sweeping through the Mid-Atlantic and northeastern U.S. today.

Basically, GOES-11 shows that Irwin is the only active and named tropical system amid the tropical ruins today.

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



October 13, 2011

This AIRS infrared image shows Tropical Depression Irwin (left) and the remnants of Jova over southwestern Mexico (right). › View larger image
This infrared image from Oct. 13, 2011 at 4:41 a.m. EDT shows Tropical Depression Irwin (left) and the remnants of Jova over southwestern Mexico (right) as blue and purple areas. The purple areas indicate strong convection and heavy rainfall still occurring, where cloud top temperatures exceed -63F/-52C.
Credit: NASA/JPL, Ed Olsen
This GOES-11 image shows Tropical Depression Irwin, the remnants of Jova, and Tropical Depression 12E. › View larger image
This GOES-11 satellite image from Oct. 13 at 8 a.m. EDT, shows Tropical Depression Irwin is still at sea (left), remnants of Jova are over southwestern Mexico, and Tropical Depression 12E was inland over southeastern Mexico. TD12E's cloud cover extends over the Yucatan Peninsula, Belize and Guatemala.
Credit: NASA/NOAA GOES Project
Satellites View Three Dying Tropical Systems in Eastern Pacific

Three tropical systems in the eastern Pacific Ocean: Tropical Depression Irwin, Post-tropical cyclone Jova, and the remnants of Tropical Depression 12E all appeared to be fading on NASA satellite imagery today.

NASA's Aqua satellite passed over the eastern Pacific at 4:41 a.m. EDT, Thursday, Oct. 13, and captured an infrared image of Tropical Depression Irwin still in open waters and the remnants of post-tropical cyclone Jova inland over central Mexico. Irwin still had some strong convection (rapidly rising air that condenses and forms thunderstorms that make up a tropical cyclone) in a very small area, while all of the punch (strong convection) was now missing from post tropical cyclone Jova. Cloud top temperatures in Irwin were still near -63F/-52C in that small area of strong convection, while cloud tops in Jova have warmed and weakened.

That small area of disorganized convection seen in the AIRS image is enabling Irwin to still be classified as a tropical depression. The National Hurricane Center noted today that "the system is on the verge of losing the convective requirement of a tropical cyclone, and Irwin is expected to become a remnant low within 24 hours."

At 5 a.m. EDT today, Oct. 13, Irwin's maximum sustained winds were near 35 mph (55 kmh). It was located about 230 miles (365 km) west-southwest of Manzanillo, Mexico near 18.3 North and 107.7 West. Irwin was moving to the northeast near 13 mph (20 kmh) and is expected to curve to the east then southeast, heading back toward the open ocean, where it is expected to fizzle out.

The remnants of post-tropical cyclone Jova dissipated over central Mexico. At 11 p.m. EDT last night, Oct. 12, the last known center of Jova was near 21.7 North and 104.2 West. At that time, Jova had maximum sustained winds near 25 knots (30 mph). By 10 a.m. EDT on Oct. 13, Jova's remnants were dissipating. Skies over Mazatlan, Mexico were mostly clear, however there were some towering cumulus clouds observed. Further south at Zacatecas Airport, Mexico, mostly cloudy skies prevailed. On the west coast, Puerto Vallarta reported overcast skies with some light drizzle.

During the morning (EDT) on Oct. 13, Tropical Depression 12E was inland over southeastern Mexico, including the Yucatan Peninsula, Belize and Guatemala. It TD12E is now a broad area of low pressure and was seen on NOAA's GOES-11 satellite imagery. The GOES-11 satellite image was created by NASA's GOES Project at the NASA Goddard Space Flight Center in Greenbelt, Md. It showed that TD12E's clouds extended from southeastern Mexico eastward into the northwestern Caribbean Sea. The National Hurricane Center currently gives TD12E a "near zero percent" chance of regenerating.

Meanwhile, it is generating disorganized showers and thunderstorms. Some of those thunderstorms contain heavy rainfall over southeastern Mexico, the Yucatan, Belize and Guatemala.

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



October 12, 2011 Satellite image of Irwin and Jova › Larger image
Irwin appears to be disorganized in this visible image from NOAA's GOES-11 satellite. The image was taken at 3 p.m. EDT on Oct. 12.
Credit: NASA/NOAA GOES Project
Tropical Storm Irwin Appears Disorganized on Satellite Imagery

Tropical Storm Irwin is struggling for survival in the eastern Pacific Ocean, and it is difficult to find the circulation center of the storm on satellite imagery today.

When NOAA's GOES-11 satellite captured an image of Irwin today, October 12, 2011 at 3 p.m. EDT, the circulation center was not apparent. The image was created at NASA's GOES Project at the NASA Goddard Space Flight Center, Greenbelt, Md.

At 11 a.m. EDT, Irwin's center (located on microwave satellite imagery) was located near 16.0 North and 110.7 West. That's about 480 miles (770 km) south of the southernmost tip of Baja California, Mexico. It had maximum sustained winds near 40 mph (65 kmh) and the National Hurricane Center forecasts slow weakening during the next couple of days, although Irwin may become a depression tonight. Irwin is suffering from wind shear created by outflow from nearby hurricane Jova and Tropical Depression 12E.

Irwin is moving to the east-northeast and is expected to turn to the east. Over the next several days, as a ridge of high pressure to the north becomes the main force in steering the storm, it is forecast to boomerang and head back west as a remnant low.

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



October 11, 2011

This infrared image of spotty cold cloud tops in Tropical Depression Irwin (left) was taken from the AIRS instrument on NASA's Aqua satellite on Oct. 11 at 4:53 a.m. EDT. › View larger image
TThis infrared image of spotty cold cloud tops in Tropical Depression Irwin (left) was taken from the AIRS instrument on NASA's Aqua satellite on Oct. 11 at 4:53 a.m. EDT. The purple areas indicate coldest cloud tops (-63F) and strongest convection, and heaviest rainfall. The powerful Hurricane Jova is seen to the right along the western Mexico coastline.
Credit: NASA/JPL/Ed Olsen
Spotty, Strong Convection Seen in NASA imagery Helps Irwin Regain Tropical Storm Status

Tropical Storm Irwin almost appeared down for the count, but spotty areas of flaring convection provided a clue to forecasters that he wasn't ready to give up yet. The cloud top temperatures were measured by a NASA instrument at a frigid -112 Fahrenheit, indicating they're very high and powerful.

An infrared image of Tropical Depression Irwin was taken from the Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite on Oct. 11 at 4:53 a.m. EDT. The infrared data revealed three areas of strong convection still occurring within the depression. Those three areas had high, very cold cloud tops (-80C/-112F) indicated strong convection, and heavy rainfall.

Irwin weakened to a tropical depression early today, Oct. 11, but by 11 a.m. EDT, was back to tropical storm status with maximum sustained winds near 40 mph (65 kmh). Those tropical storm- winds extend out 60 miles from the center, making Irwin a small tropical storm, only 120 miles in diameter.

Irwin is centered about 620 miles (1000 km) south-southwest the southern tip of Baja California, Mexico, near 15.3 North and 115.0 West. Irwin is moving to the east at 8 mph (12 kmh) and is expected to continue that direction today, but turn to the east-northeast on Oct. 12.

The National Hurricane Center discussion for Irwin's future indicates that the strengthening is only temporary because of stable air and increasing wind shear. If infrared data shows Irwin's cloud tops warming, that means they're falling and there's not as much energy in the atmosphere. If that happens, Irwin may drop to depression status again over the next couple of days.

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



October 7, 2011

Infrared image of Hurricane Irwin was taken by AIRS on Oct. 6 at 5:05 p.m. EDT. › View larger image
This infrared image of Hurricane Irwin was taken from the AIRS instrument on NASA's Aqua satellite on Oct. 6 at 5:05 p.m. EDT. Hurricane Irwin had a large area of very cold clouds, and strong thunderstorms surrounding its center, and in bands of thunderstorms wrapping around the center of circulation. Tropical Storm Jova lies just to the east.
Credit: NASA/JPL, Ed Olsen
NASA Infrared Image Shows an Organized Hurricane Irwin in Pacific

A look at Hurricane Irwin's cloud-top temperatures from NASA's Aqua satellite showed that the storm is organized and strong, despite the lack of an eye on infrared imagery.

NASA's Aqua satellite takes infrared data of tropical cyclones from the Atmospheric Infrared Sounder (AIRS) instrument. In an infrared image on Oct. 6 at 5:05 p.m. EDT, Hurricane Irwin had a large area of very cold clouds and strong thunderstorms surrounding its center. In addition, cold, high clouds were seen in bands of thunderstorms wrapping around the center of circulation. Those cold cloud top temperatures exceeded -63 Fahrenheit (-52 Celsius) and were areas of heavy rainfall. The tightly-curved bands of thunderstorms indicate that Irwin continued to consolidate and intensify. Despite the organization and strength, infrared imagery still did not show an eye.

At 11 a.m. EDT on October 7, Irwin continued to strengthen. At that time, Irwin's maximum sustained winds were near 85 mph (140 kmh). It is expected to strengthen more before running into adverse conditions. It was located about 925 miles (1,490 km) southwest of the southernmost tip of Baja California, Mexico, near 13.9 North and 120.4 West. Irwin was moving to the west-northwest near 8 mph (13 kmh).

Over the latter half of the weekend, wind shear is forecast to increase from the east. Wind shear weakens tropical cyclones, and is expected to have that effect on Irwin as the hurricane turns toward the east in the next couple of days. Irwin is also expected to slow down over the next couple of days.

The National Hurricane Center currently takes Hurricane Irwin toward a landfall in west-central Mexico late next week after Hurricane Jova's landfall.

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



October 6, 2011

Infrared image from AIRS shows the birth of Tropical Storm Irwin and Tropical Depression 10E. › View larger image
This infrared image from the AIRS instrument on NASA's Aqua satellite shows the birth of two tropical cyclones on Oct. 6. The larger and more powerful Tropical Storm Irwin (left) and the smaller, more compact Tropical Depression10E (right). The purple areas indicate the coldest, highest cloud tops and strongest thunderstorms.
Credit: NASA/JPL, Ed Olsen
NASA's Aqua Satellite Sees Birth of Two Tropical Cyclones in Eastern Pacific

The tropics in the eastern Pacific were quiet for a couple of days after Hurricane Hilary dissipated, and today gave birth to Tropical Depression 10 and Tropical Storm Irwin. NASA's Aqua satellite captured an infrared image of both storms and saw the powerful convection in the center of Irwin that enabled the storm to go from a depression to a tropical storm in a short time.

The eleventh tropical depression quickly grew into Tropical Storm Irwin this morning, as strong convection surged around its center of circulation. That convection (rising air that creates the thunderstorms that power a tropical cyclone) was seen in infrared imagery taken early this morning, Oct. 6, from the Atmospheric Infrared Sounder (AIRS) instrument aboard NASA's Aqua satellite. The cold cloud tops from those strong thunderstorms were colder than -63 Fahrenheit (-52 Celsius) and represented the strength in the core of Irwin.

At 11 a.m. today, Oct. 6, Tropical Storm Irwin's maximum sustained winds had grown to 40 mph, after forming as a depression just 5 hours before. Irwin was located about 855 miles (1,375 km) south-southwest of the southern tip of Baja California, Mexico near 12.4 North and 116.8 West. It was moving away from land to the west-northwest near 6 mph (9 kmh). The National Hurricane Center expects Irwin to turn to the north and then north-northeast tomorrow. Irwin is expected to strengthen slowly in the next 48 hours. Minimum central pressure was 1005 millibars.

Closer to land, NASA's Aqua satellite saw a smaller Tropical Depression 10E. Tropical Depression 10E (TD10E) appears pretty close to Tropical Storm Irwin on the AIRS infrared imagery. It is located to the east-southeast of Tropical Storm Irwin, and it appears to be a smaller, more compact, rounded area of strong convection. Specifically, TD10E is located near 10.3 North and 105.8 West, about 610 miles south of Manzanillo, Mexico. It has maximum sustained winds near 35 mph (55 kmh) and is moving to the west-northwest near 8 mph (13 kmh). The AIRS infrared data shows strong convection around the southwestern edge of the center of circulation, indicating that TD10E could also become a tropical storm shortly.

The National Hurricane Center noted that "The tropical cyclone is forecast to remain over warm waters and in a low (wind) shear environment during the next several days" and predicts it could become a hurricane in two or three days. By mid-day on Saturday, Oct. 8, the National Hurricane Center forecast projects TD10E to change course and "recurve ahead of a large trough (elongated area of low pressure) diving southeastward across the southwest United States and the Baja Peninsula."

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