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Hurricane Season 2010: Tropical Storm Omais (Western Pacific Ocean)
03.26.10
 
March 26, 2010

AIRS image of Omais> View larger image
AIRS infrared image of Omais on March 25 at 12:53 p.m. EDT revealed that its high thunderstorms (blue and purple) were scattered and limited. Credit: NASA JPL, Ed Olsen
Winds Blow Off Omais' Thunderstorm Tops

Tropical Storm Omais is fading fast in the northwestern Pacific Ocean, and will dissipate over the weekend according to the Joint Typhoon Warning Center. When NASA's Aqua satellite flew over Omais late on March 25, it already showed signs of falling apart.

At 0900 UTC (5 a.m. EDT)on Friday, March 26, Tropical Storm Omais was barely hanging onto tropical storm strength with maximum sustained winds near 39 mph. It was located about 655 nautical miles southwest of the island of Iwo To (formerly Iwo Jima) near 18.3 North and 132.1 East. It was moving north-northeastward at 12 mph (11 knots) and quickly losing its tropical characteristics.

The infrared image from the Atmospheric Infrared Sounder (AIRS) instrument that flies on NASA's Aqua satellite captured an image of Omais on March 25 at 16:53 UTC (12:53 p.m. EDT) and revealed that its convection (rapidly rising air that creates the thunderstorms that power a tropical cyclone) was scattered and limited. It appears as if the convection center of circulation was blown apart – which is exactly what the wind shear had done to those high thunderstorm tops.

There is an upper level trough nearby and that has increased the vertical wind shear has elevated to near 46 mph (40 knots)! The system is expected to become fully extratropical on Saturday, March 27.

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



March 25, 2010

The Aqua satellite captured Omais' cold thunderstorm cloud tops (purple) on March 25. > View larger image
NASA's Aqua satellite captured cold thunderstorm cloud tops (purple) in the center of Tropical Storm Omais in this infrared image of March 25 at 12:41 a.m. EDT. Omais has doubled in size overnight.
Credit: NASA JPL, Ed Olsen
The clouds associated with the cold front to the northwest of Omais are visible (top left). > View larger image
NASA's Aqua satellite captured this visible image of Tropical Storm Omais on March 25. On the bottom left corner of the storm, a cluster (circle) of high thunderstorms is visible on the storm's southwestern edge. The clouds associated with the cold front to the northwest of Omais are also visible (top left).
Credit: NASA JPL, Ed Olsen
Tropical Storm Omais Weakens and Doubles in Size

Tropical storm Omais has run into wind shear in the northwestern Pacific Ocean, but as it has weakened overnight it has also doubled in size. NASA's Aqua satellite has captured both infrared and visible images early this morning of the larger Omais.

Late yesterday, March 24, Omais strengthened to (63 mph) 55 knots and now that it has run into an environment with stronger wind shear, it has already weakened. The wind shear has increased because of the approach of a frontal system which is currently about 215 nautical miles northwest of the storm.

This morning at 0900 UTC (5 a.m. EDT) Omais' maximum sustained winds were down to 52 mph (45 knots). Omais, known in the Philippines as "Agaton," is now about 515 miles north-northwest of Palau, Micronesia, near 15.3 North and 131.5 East. It’s a slow moving storm, creeping along at 5 mph (4 knots) in a north-northwesterly direction.

As the storm continues to weaken, the reach of its tropical storm-force winds is expanding over a larger area. On March 24, tropical storm-force winds of 39 mph extended 30 miles out from the center. Now that Omais has weakened winds of that same strength extend as far as 65 miles from the center, so the area of tropical storm-force winds has more than doubled overnight.

The Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite captured cold thunderstorm cloud tops in the center and southwestern corner of Tropical Storm Omais on March 25 at 12:41 a.m. EDT. The cluster of high thunderstorms on the southwestern edge is easily seen in today's AIRS visible image, as are the clouds associated with the cold front to the northwest of Omais.

As the cold front approaches, cooler and drier air associated with it will prevent cloud formation (and thunderstorm development), and vertical wind shear will increase. As a result, Omais is expected to dissipate over the next day and a half.

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



March 24, 2010

The AIRS instrument on NASA's Aqua satellite caught the eastern half of Tropical Storm Omais as it flew overhead. > View larger image
On March 24 at 0359 UTC the Atmospheric Infrared Sounder instrument on NASA's Aqua satellite caught the eastern half of Tropical Storm Omais as it flew overhead, and noticed the highest, coldest (purple) thunderstorms were in the center of the storm.
Credit: NASA JPL, Ed Olsen
02W Renamed Tropical Storm Omais, Staying at Sea

Tropical Cyclone 02W still has maximum sustained winds near 46 mph but one thing changed: it has been named "Omais."

NASA satellites have watched Omais stay safely away from land in the Philippine Sea. On March 24 at 0359 UTC (March 23 at 11:59 p.m. EDT), the Atmospheric Infrared Sounder instrument on NASA's Aqua satellite caught the eastern half of Tropical Storm Omais as it flew overhead, and noticed the highest, coldest thunderstorms were in the center of the storm. The infrared instrument also noticed that sea surface temperatures were still above 80 degrees Fahrenheit in the storm's vicinity.

At 1500 UTC (11 a.m. EDT) today, March 24, Tropical Storm Omais was about 350 nautical miles north-northwest of Palau, Micronesia, near 13.3 North and 133.5 East. Omais is moving northwest at 15 mph (13 knots) and generating waves up to 18 feet high in the Philippine Sea.

Omais is expected to continue swinging toward the north over the next couple of days where it will dissipate by the weekend.

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



March 23, 2010

Aqua showed some strong convection (purple) near the 02W's center. > View larger image
NASA's Aqua satellite captured an infrared image of Tropical Storm 02W on March 23 at 0453 UTC (12:53 a.m. EDT) far to the east of the Philippines (left). There was still some strong convection (purple) near the storm's center.
Credit: NASA JPL, Ed Olsen
TRMM showed that there is deep convection (red) wrapping around 02W's center from the southeast to the southwest. > View larger image
The TRMM satellite captured a microwave image of 02W earlier today and it showed that there is deep convection (red) wrapping around the storm's center from the southeast to the southwest.
Credit: NASA TRMM
Tropical Storm 02W Leaves Guam and Micronesia with High Surf and Swells

The National Weather Service in Guam has posted advisories for small craft advisories and high surf advisories for Guam and the surrounding region, including Micronesia. NASA's Aqua and TRMM satellites captured two views of limited areas of convection in the storm today.

Tropical Storm 02W is moving farther away from Yap state and into open waters of the Southern Pacific Ocean today, but it's leaving rough waters behind. At 1500 UTC (11 a.m. EDT) on March 23, Tropical Storm 02W was about 75 nautical miles north-northwest of Yap, near 11.0 North and 137.1 East and moving west-northwestward near 13 mph (11 knots). 02W has maximum sustained winds near 39 mph (35 knots). In open waters, 02W is creating 14-foot high waves.

The National Weather Service in Guam has posted advisories for today and tomorrow. A small craft advisory and high surf advisory are in effect for Guam, Rota, Tinian and Siapan coastal waters. The advisory is in effect until 6 a.m. local time, Wednesday, March 24. Seas around 10 feet tonight will produce marine conditions hazardous to small craft. In addition...winds may reach 22 knots at times overnight. The high surf advisory is now in effect until 6 a.m. local time Wednesday. Surf will be hazardous 10 to 12 feet along east facing reefs tonight, falling below hazardous levels to 8 to 10 feet early Wednesday morning.

Micronesia is also under a high surf advisory for all shores. The National Weather Service Bulletin from Guam noted "Hazardous surf of 12 to 14 feet will persist along all shores through Wednesday...then gradually subside below hazardous levels on Wednesday night or early Thursday morning. Coastal inundation of a foot above high tide is possible tonight." These swells and wind waves are a result of Tropical Storm 02W as it moves away from the area. The swells and surf conditions will be felt across the Republic of Palau and Yap state through tomorrow.

As 02W keeps moving away from Yap, animated multispectral satellite imagery showed convective banding of thunderstorms wrapping into the storm's low level circulation center. The Tropical Rainfall Measuring Mission (TRMM) satellite captured a microwave image of 02W earlier today and it showed that there is deep convection (thunderstorms) wrapping around the storm's center from the southeast to the southwest indicating there's still some punch in the tropical storm.

The Atmospheric Infrared Sounder (AIRS) instrument aboard NASA's Aqua satellite captured an infrared image of Tropical Storm 02W on March 23 at 0453 UTC (12:53 a.m. EDT) far to the east of the Philippines. There was still some strong convection near the storm's center.

The forecast from the Joint Typhoon Warning Center notes that 02W should continue moving northwestward and should run into a trough, an elongated area of low pressure, which should weaken 02W. Thereafter, it will be subjected to increasing vertical wind shear which will weaken the storm further.

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



March 22, 2010

Tropical Depression 02W's high and cold (purple) thunderstorms. > View larger image
This infrared image from NASA's Atmospheric Infrared Sounder instrument on the Aqua satellite showed some high cold (purple) thunderstorms in Tropical Depression 02W.
Credit: NASA JPL, Ed Olsen
Tropical Depression 02W Forms in Northwestern Pacific

The second tropical depression of the northwestern Pacific tropical cyclone season has formed and is currently located about 235 miles east-southeast of Yap, Micronesia. NASA's Aqua satellite captured infrared, microwave and visible images of Tropical Depression 02W (TD 02W) early this morning.

When NASA's Aqua satellite flew over TD 02W this morning, Monday, March 22 at 0405 UTC (12:05 a.m. EDT), infrared imagery showed a large area of strong convection in the storm's center, where thunderstorm cloud tops were highest. Those cloud top temperatures were colder than -63 degrees Fahrenheit, indicating strong thunderstorms with moderate to heavy rainfall.

By 11 a.m. EDT (1500 UTC or 1 a.m. local time) today, TD 02W had maximum sustained winds near 35 mph (30 knots) and was near 8.4 degrees North latitude and 141.4 degrees East longitude. TD 02W is about 100 miles southeast of Fais, 150 miles east-southeast of Ulithi and 235 miles east-southeast of Yap. It was moving northwest near 10 mph (9 knots), and generating 10-foot high waves.

A tropical storm warning remains in effect for Yap: Fais and Ulithi in Yap State. The tropical storm watch for Ngulu in Yap state and Kayangel in the Republic of Palau has been cancelled. TD 02W is forecast to pass between Yap and Ulithi late this afternoon (local time). Tropical depression 02W is expected to slowly intensify...and be a minimal tropical storm by the time it reaches Yap and Ulithi.

Rising seas generated by TD 02W's winds will cause high surf across the Republic of Palau and Yap State through Wednesday, March 24.

Updates can be obtained by the National Oceanic and Atmospheric Administration's Forecast Office in Guam at: http://www.prh.noaa.gov/guam/

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