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Hurricane Miriam (Eastern Pacific Ocean)
09.28.12
 
GOES-15 captured this infrared image of Tropical Storm Miriam's remnants and Tropical Storm Norman › View larger image
On Sept. 28 at 1445 UTC (10:45 a.m. EDT), NOAA's GOES-15 satellite captured this infrared image of Tropical Storm Miriam's remnants and Tropical Storm Norman just as it was classified a tropical storm. Both storms are in the Eastern Pacific, off the coast of western Mexico.
Credit: NASA GOES Project
NASA Sees Tropical Storm Miriam Takes Final Bow, Replaced by Norman

Tropical Storm Miriam is taking her final bow in the eastern Pacific, and Tropical Storm Norman replaced her on the stage of the Eastern Pacific Ocean.


Miriam Breathes Her Last Breath

The National Hurricane Center issued their last advisory on Miriam on Sept. 27 at 11 p.m. EDT when it became a remnant low pressure area. At that time, the center of post-tropical cyclone Miriam was located near latitude 22.0 north and longitude 116.7 west, just over 400 miles west of the southern tip of Baja California. Miriam had maximum sustained winds near 30 knots (35 mph/55 kmh).

NOAA's GOES-15 satellite captured an infrared image of Tropical Storm Miriam and a developing low pressure area in the Eastern Pacific on Sept. 28 at 1145 UTC (7:45 a.m. EDT), off the coast of western Mexico. Infrared imagery showed that Miriam had not produced deep convection and strong thunderstorms since 8 a.m. EDT on Sept. 27, so it was downgraded to a remnant low.

According to the National Hurricane Center (NHC), ocean swells generated by Miriam should begin to subside today, Friday, Sept. 28 especially along the western coast of the southern and central Baja Peninsula.


Newborn Norman Causes Tropical Storm Warning in Mexico

As Miriam fades, Tropical Storm Norman just formed near the Baja mid-day on Sept. 28. The GOES-15 satellite image on Sept. 28 clearly showed Tropical Storm Norman's birth, about 90 miles south-southeast of Baja California. The low appeared somewhat poorly defined on the satellite image, but is producing a large area of showers and thunderstorms within a few hundred miles of the coast of western Mexico.

A Tropical Storm Warning is in effect for the west coast of mainland Mexico from La Cruz, northward to Huatabampo.

At 11 a.m. EDT, Norman's maximum sustained winds were near 45 mph (75 kmh). Norman was centered about 85 miles (135 km) east of Cabo San Lucas, Mexico, near latitude 22.8 north and longitude 108.6 west. Norman is moving toward the north near 16 mph (26 kmh) and a northward motion is expected to continue for the next day or so.

Norman's center is expected to make landfall in the warning area this evening or tonight, Sept. 28, local time (Pacific Daylight time).

As the low moves north, coastal areas between Mazatlan and Huatabampito should expect heavy rainfall and gusty winds. Rainfall as much as 4 to 8 inches can be expected, according to the National Hurricane Center. Residents should be prepared for heavy rain and flooding over the next couple of days.

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



Sept. 27, 2012

AIRS image of Miriam › View larger image
This infrared image was created from AIRS data of Tropical Storm Miriam on Sept. 26 at 2047 UTC off the coast of Baja California. Strongest thunderstorms with very cold cloud top temperatures appear in purple surrounding north, east and south of the center of circulation.
Credit: NASA JPL/Ed Olsen
NASA Sees a Western Weakness in Tropical Storm Miriam

NASA infrared satellite imagery showed Tropical Storm Miriam had strong convection and thunderstorm activity in all quadrants of the storm on Sept. 26, except the western quadrant. That activity waned dramatically in 24 hours because of strong wind shear and cooler sea surface temperatures.

The Atmospheric Infrared Sounder (AIRS) instrument that flies aboard NASA's Aqua satellite captured infrared data on Tropical Storm Miriam on Sept. 26 at 2047 UTC, when it was off the coast of Baja California. Strongest thunderstorms with very cold cloud top temperatures appear to surround north, east and south of the center of circulation. By Sept. 27, only the northern quadrant of the storm appeared to have those strong thunderstorms.

Miriam appears to be weakening quickly because of strong wind shear and cooler waters.

At 11 a.m. EDT on Sept. 27, Miriam's maximum sustained winds had decreased to near 40 mph (65 kmh) and further weakening is expected. The National Hurricane Center noted that Miriam could become a remnant low later today or tomorrow, Sept. 28.

The center of Tropical Storm Miriam was located near latitude 22.2 north and longitude 116.3 west. Miriam is moving northwest near 6 mph (9 kmh) and is expected to turn west.

Regardless of the weakening condition of the storm, Miriam is still generating dangerous ocean swells along the south and west coasts of the southern and central Baja peninsula today but those will begin to gradually subside by Sept. 28.

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



Sept. 26, 2012

Tropical Storm Miriam was captured by NOAA's GOES-15 satellite on Sept. 26, 2012 at 10:45 a.m. EDT › View larger image
This visible image of Tropical Storm Miriam was captured by NOAA's GOES-15 satellite on Sept. 26, 2012 at 10:45 a.m. EDT off the coast of Baja California. The strongest thunderstorms were in a large band of thunderstorms north and northwest of the center.
Credit: NASA GOES Project
Satellite Sees Miriam Weaken to a Tropical Storm

Once a powerful hurricane, Miriam is now a tropical storm off the coast of Baja California, Mexico. Tropical Storm Miriam was seen in the Eastern Pacific Ocean by NOAA's GOES-15 satellite, and the visible image revealed that the strongest part of the storm was north and west of the center.

NOAA's GOES-15 satellite sits in a fixed position over the western U.S. that allows it to monitor the Eastern Pacific Ocean and it captured a visible image of Tropical Storm Miriam on Sept. 26, 2012 at 10:45 a.m. EDT off the coast of Baja California. The image, created by NASA's GOES Project at NASA's Goddard Space Flight Center in Greenbelt, Md. showed that the strongest thunderstorms were north and northwest of the center in a large band, wrapping around the storm's center.

Wind shear is taking its toll on Miriam. The National Hurricane Center noted there is an increasing "separation between the low- to mid-level centers of the storm (think of the storm as having multiple layers) due to 20-25 knots of southwesterly shear associated with a shortwave trough (elongated area of low pressure) rotating around the northwestern side of the storm.

At 11 a.m. EDT on Sept. 26, Tropical Storm Miriam had maximum sustained winds near 65 mph (100 kph), dropping from 70 mph (100 kmh) just six hours before. It was located about 425 miles (680 km) west-southwest of the southern tip of Baja California Miriam was moving slowly at 6 mph (9 kmh) to the north-northwest and away from the coast. Miriam's minimum central pressure was near 992 millibars.

A Miriam continues to pull away from Baja California, rough ocean swells will keep affecting the south and west coasts today, Sept. 26, and tomorrow, Sept. 27. By Sept. 28, Friday, the ocean swells will gradually begin to subside.

Miriam is moving into a region where wind shear is forecast to increase and sea surface temperatures will fall. Those are two factors that will contribute to the weakening of the tropical storm over the next several days.

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



Sept. 25, 2012

Miriam › View larger image
NASA's Aqua satellite flew over Hurricane Miriam on Sept. 24 at 21:00 UTC and the MODIS instrument captured this image off Mexico's west coast.
Credit: NASA/Goddard/MODIS Rapid Response Team.)
Category 2 Hurricane Miriam Seen in E. Pacific by NASA Satellite

The MODIS instrument that flies aboard NASA's Aqua and Terra satellites provide some of the most clear and stunning imagery of tropical cyclones, and captured a visible image of Category 2 hurricane Miriam off the western coast of Mexico.

MODIS stands for the Moderate Resolution Imaging Spectroradiometer. Terra's MODIS and Aqua's MODIS view the entire Earth's surface every 1 to 2 days, acquiring data in 36 spectral bands, or groups of wavelengths. NASA's Aqua satellite flew over Hurricane Miriam on Sept. 24 at 21:00 UTC and the MODIS instrument captured a visible image of Hurricane Miriam off Mexico's west coast. The MODIS image showed that Miriam's eye was covered by high clouds, yet the eye is still about 30 nautical miles wide. Cloud top temperatures around the eye have cooled in infrared imagery, which indicates thunderstorms around the eye still have strong uplift and are shooting high into the troposphere.

On Sept. 25 at 5 a.m. EDT Hurricane Miriam's maximum sustained winds were near 105 mph (165 kmh), making it a category 2 hurricane on the Saffir-Simpson hurricane scale. Miriam 's hurricane-force winds extend only 30 miles (45 km) from the center. Slow weakening is forecast during the next 48 hours, according to the National Hurricane Center.

Miriam's center was located near latitude 18.7 north and longitude 114.3 west. Miriam is moving in a northwesterly direction near 6 mph (9 kmh) and is expected to turn to the north-northwest later on Sept. 25, followed by a turn to the north. Miriam's estimated minimum central pressure is 968 millibars.

Although Miriam is off-shore, the hurricane is producing very rough seas along the south and western coasts of the central Baja Peninsula, and those conditions will continue for the next several days.

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



Sept. 24, 2012

infrared image of Miriam › View larger image
This infrared image of Tropical Storm Miriam was captured by the Atmospheric Infrared Sounder (AIRS) instrument aboard NASA's Aqua satellite. The image was taken on Sept. 23 at 2011 UTC and revealed that Miriam had a huge area (purple) of strong thunderstorms and heavy rainfall around the center of circulation.
Credit: NASA JPL, Ed Olsen
NASA's Satellite Saw 'Power-Trigger' Around Hurricane Miriam's Center

NASA's Aqua satellite revealed a large area of powerful thunderstorms around the center of Tropical Storm Miriam on Sept. 23 as it tracked through the Eastern Pacific Ocean. That power was the trigger that helped Miriam rapidly intensify into a major hurricane on Sept. 24.

NASA's Aqua satellite passed over the eastern Pacific Ocean on Sept. 23 and the Atmospheric Infrared Sounder (AIRS) instrument captured an infrared image of Tropical Storm Miriam's cloud top temperatures. Tropical Storm Miriam is born that day, about 640 miles (1,025 km) south-southeast of the southern tip of Baja California. Cloud top temperatures are an indication of uplift in a storm. Uplift is the push of air upward that allows formation of towering clouds and thunderstorms that make up a tropical cyclone. The infrared data indicated a large area of strongest thunderstorms and heaviest rainfall surrounding the center of circulation. Those cloud top temperatures exceeded -63 Fahrenheit (-52 Celsius).

On Friday, Sept. 24 at 11 a.m. EDT, Tropical Storm Miriam became an eastern Pacific hurricane with maximum sustained winds near 120 mph (195 kmh). Miriam was located about 410 miles (655 km) south-southwest of the southern tip of Baja California, Mexico, near latitude 17.7 North and longitude 112.9 West. Miriam is moving northwest near 12 mph (19 kmh) and a gradual turn to the west and southwest is expected later.

Visible imagery from NOAA's GOES-15 satellite suggests the formation of a small eye, while NASA's Tropical Rainfall Measuring Mission (TRMM) satellite data suggest that an outer eyewall is forming. The National Hurricane Center noted that barring an eyewall replacement, Miriam could strengthen even more in the next day.

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