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Hurricane Season 2008: Tropical Storm Alma (Eastern Pacific Ocean)
05.29.08
 
June 05, 2008

Alma and Arthur Bring Heavy Rains to Central America

Map of Alma and Arthur storm paths Credit: Hal Pierce (SSAI/NASA's Goddard Space Flight Center)
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Alma, the first named storm of the season in the eastern Pacific, made landfall on the northern Pacific coast of Nicaragua as a strong tropical storm. After making landfall, the system continued northward moving further inland over the high terrain of Honduras where it dissipated. Immediately thereafter, Arthur, the first named storm of the Atlantic season, formed in close proximity from a separate area of low pressure in the northwestern Caribbean as it was moving ashore over Belize. Arthur also dissipated as it moved deeper into the Yucatan Peninsula over southern Mexico. The combination of Alma and Arthur brought heavy rains to parts of Central America.

The Tropical Rainfall Measuring Mission satellite (also known as TRMM) has been in service for over 10 years now and continues to provide a steady stream of rainfall data for the Tropics. The TRMM-based, near-real time Multi-satellite Precipitation Analysis (TMPA) at the NASA Goddard Space Flight Center provides estimates of rainfall over the global Tropics. TMPA rainfall totals associated with Alma and Arthur are shown for the period 27 May to 4 June 2008. Solid black lines show the path of each storm (Arthur to the north and Alma to the south) with appropriate storm symbols marking the 00Z and 12Z positions. The highest rainfall totals for the period exceed 400 mm (~16 inches, shown in red) over coastal Belize and are mainly associated with the formation and passage of Arthur. A swath of 100+ mm (~4+ inches, shown in green) stretches across northern Guatemala and southern Mexico. Farther to the south, an area of 200 to 300+ mm of rain (~8 to 12+ inches, shown in yellow and orange) covers Costa Rica. This is associated with moisture being drawn up by the counterclockwise circulation of Alma. Amounts where Alma actually made landfall are less, on the order of 100 mm (~4 inches). So far at least 9 deaths are being blamed on the two storms across the region.

TRMM is a joint mission between NASA and the Japanese space agency JAXA.

Text credit: Steve Lang, SSAI/NASA's Goddard Space Flight Center



June 02, 2008

Atlantic Ocean Hurricane Season Starts Early With a Gender Bender

Alma, the first and record-breaking Tropical Storm in the eastern Pacific Ocean formed the last weekend in May. Alma's remnants re-generated into the first tropical storm in the Atlantic Basin, where it was re-named Arthur from the Atlantic Ocean storm name list. Now, it may be headed back into the Pacific!

Tropical Storm Alma has established three new records for an eastern Pacific storm. Alma was the first tropical storm (in the available records) to make landfall on the Pacific coast of Central America when she made landfall on May 29. She also made landfall farther east than any previous eastern pacific tropical cyclone, and was the first to do so on the Pacific coast of Nicaragua.

At 1:00 p.m. EDT on Saturday, May 31, what was once Alma, had downgraded significantly into an area of low pressure that had moved across Central America and into the northwestern Caribbean Sea. Then it strengthened back into a tropical storm as it was crossing the Belize coast, and was given the name Arthur, as it became the first storm in the Atlantic Ocean basin. The National Hurricane Center noted “This system is not designated Tropical Storm Alma because the surface center of Alma dissipated over the high terrain of Central America yesterday.”

Arthur’s Final Call

By 11:00 p.m. EDT, Sunday, May 31, the National Hurricane Center issued its seventh and final advisory on Arthur, as he continued to deteriorate, while still generating heavy rains (up to 10 inches) over portions of Belize.

At that time, Arthur was located near 17.4 north and 91.3 west, near the northwester border between Guatemala and Mexico. Arthur was moving about 6 mph to the southwest, with sustained winds near 30 mph. The minimum central pressure was 1006 millibars at that time.

Arthur image from AIRS on June 1, 2008 These infrared images of Arthur (click on images to enlarge) were created by data from the Atmospheric Infrared Sounder (AIRS), an instrument that flies aboard NASA's Aqua satellite. The top image from June 1 at 7:35 UTC (3:35 a.m. EDT) shows Arthur in the western Caribbean Sea.

The AIRS images show the temperature of the cloud tops or the surface of the Earth in cloud-free regions. The lowest temperatures (in purple) are associated with high, cold cloud tops that make up the top of Arthur. The infrared signal of the AIRS instrument does not penetrate through clouds. Where there are no clouds the AIRS instrument reads the infrared signal from the surface of the Earth, revealing warmer temperatures (red).

Arthur image from AIRS on June 2, 2008 Could Alma-Arthur Have As Many Lives as a Cat?

The second image, from Monday, June 2 at 8:17 UTC (4:17 a.m. EDT) shows part of Arthur’s circulation (purple) re-entering the eastern Pacific Ocean. At 5:00 a.m. EDT, the National Hurricane Center noted “A large area of showers and thunderstorms extends from the Gulf of Tehuantepec southward for a few hundred miles over the eastern Pacific. Upper-level winds are expected to become a little more favorable for development and a tropical depression could form within this area during the next day or two.”

Image credit: NASA/JPL, Text credit: Rob Gutro/Goddard Space Flight Center


June 1, 2008

2008 Hurricane Seasons Begin in Eastern Pacific and Atlantic

Satellite images of Alma and Arthur Credit: Jesse Allen, using data obtained from the Goddard Land Processes data archives (LAADS)
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> May 29 image (higher resolution)
> May 31 image (higher resolution)
Both the eastern Pacific and Atlantic hurricane seasons of 2008 were inaugurated within a few days of each other in late May and the first days of June. That these two “season openers” occurred in the same week wasn’t simply a coincidence: they were related. On May 29, thunderstorms over the Pacific Ocean about 250 miles southwest of Nicaragua became Tropical Storm Alma: the first named storm of the 2008 eastern Pacific season. Alma moved north and made landfall on the coast of Nicaragua. As it crossed Central America, the storm fell apart as a circulating system, but the remaining moisture and energy emerged over the Gulf of Honduras to the north. There, on May 30, those remnants spun up into Tropical Storm Arthur: the first named storm of the Atlantic season.

On Thursday, May 29, the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite observed Tropical Storm Alma as it was making landfall in Nicaragua. The familiar shape of a hurricane -- a pinwheel of clouds spinning around an obvious eye -- is hard to make out in the image. The center of circulation was just offshore, south of the city of León. The remains of the storm headed north, and by May 31, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite collected the bottom image, they were helping to fuel Tropical Storm Arthur. The image shows the storm making landfall at Belize.

According to the National Hurricane Center, Alma was the first hurricane ever to make landfall on the Pacific coast of Nicaragua, and it was the first Pacific hurricane to strike anywhere on the coast of Central America since 1949.

Text Credit: Rebecca Lindsey



May 30, 2008, second update
Tropical Storm Alma Enters the Hurricane Record Books

AIRS image of Alma Credit: NASA/JPL
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Hurricane Season 2008 in the Eastern Pacific is already off to a record-breaking start. In fact, Tropical Storm Alma has established three new records for an eastern Pacific storm.

Tropical Storm Alma came ashore at noon on Thursday, May 29 on the Pacific Coast of Nicaragua. The National Hurricane Center notes that Alma is the first tropical storm (in the available records) to make landfall on the Pacific coast of Central America. It also made landfall farther east than any previous eastern pacific tropical cyclone, and was the first to do so on the Pacific coast of Nicaragua.

By 5:00 a.m. PDT (8:00 a.m. EDT) on Friday, May 30, 2008 Alma had weakened from a tropical storm to a tropical depression and was fast degrading into a broad area of low pressure. Alma’s center was estimated near latitude 15.0 degrees north and longitude 88.0 west or inland over Honduras about 85 miles (35 km) northwest of Tegucigalpa. Nicaragua has already discontinued tropical storm warnings.

The depression was moving north-northwest near 12 mph and is expected to turn to the northwest. On this track Alma’s remnants will be moving over western Honduras today and could reach Guatemala or Belize late today or early Saturday, May 31.

Maximum sustained winds have decreased to near 25 mph (40 km/hr) with higher gusts. Alma is expected to become a remnant low later today, May 30. Estimated minimum central pressure is 1006 millibars.

The biggest threat Alma poses is huge amounts of rainfall, from 10 to 15 inches over parts of Central America from Costa Rica northwestward into areas in Nicaragua, Honduras, El Salvador, Guatemala and Belize. Some areas in high terrain may even see up to 20 inches, which could produce flash flooding and mudslides.

This infrared image of Alma was created on May 29 at 19:35 UTC (5:45 p.m. EDT) by data from the Atmospheric Infrared Sounder (AIRS), an instrument that flies aboard NASA's Aqua satellite. That was almost six hours after Alma made landfall.

This AIRS image shows the temperature of the cloud tops or the surface of the Earth in cloud-free regions. The lowest temperatures (in purple) are associated with high, cold cloud tops that make up the top of Alma (shown as the circular purple area on this satellite image). The infrared signal of the AIRS instrument does not penetrate through clouds. Where there are no clouds the AIRS instrument reads the infrared signal from the surface of the Earth, revealing warmer temperatures (red).

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



May 30, 2008, first update

2008 East Pacific Hurricane Season Begins with Tropical Storm Alma

TRMM image of Tropical Storm Alma Credit: Hal Pierce, SSAI/NASA's Goddard Space Flight Center
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The 2008 East Pacific hurricane season, which officially began on May 15, got started with the formation of Tropical Storm Alma off the coast of Central America. Tropical Depression 1E (TD #1E) formed from a broad area of low pressure about 50 miles (80 km) off the west coast of Costa Rica on the evening (local time) of 28 May 2008. TD #1E moved northward and strengthened over night as it approached the coast of Nicaragua. It was named Tropical Storm Alma early on the morning of the 29th. Alma continued moving north and made landfall on the northern Pacific coast of Nicaragua near the city of Leon early in the afternoon (local time) as a strong tropical storm with sustained winds estimated at 65 mph by the National Hurricane Center (NHC). In doing so, Alma set several records. According to NHC, Alma was the first tropical storm to make landfall on the Pacific coast of Central America, the first to make landfall on the Pacific coast of Nicaragua, and made landfall farther east then any previous East Pacific tropical cyclone.

The Tropical Rainfall Measuring Mission satellite (known as TRMM) was placed into service in November of 1997. From its low-earth orbit, TRMM has been providing valuable images and information on tropical cyclones around the Tropics using a combination of passive microwave and active radar sensors, including the first precipitation radar in space. TRMM captured this image of Alma just after it made landfall. The image was taken at 23:33 UTC (4:33 pm PDT) 29 May 2008 and shows the horizontal distribution of rain intensity (top down view) as viewed by the TRMM satellite. Rain rates in the center swath are from the TRMM Precipitation Radar (PR), and rain rates in the outer swath are from the TRMM Microwave Imager (TMI). The rain rates are overlaid on infrared (IR) data from the TRMM Visible Infrared Scanner (VIRS). TRMM confirms that although small, Alma was fairly well organized. The center of circulation is still well defined near the Nicaraguan border with Honduras by a distinct ring of moderate intensity rain (green ring). A few areas of heavier rain (shown in red) are also visible in the western part of the storm. The storm was initially blamed for 1 death but still poses a flooding threat especially when combined with the steep terrain in the region.

TRMM is a joint mission between NASA and the Japanese space agency JAXA.

Text credit: Steve Lang, SSAI/NASA's Goddard Space Flight Center



May 29, 2008, second update

TD 1-E Becomes Tropical Storm Alma in the Eastern Pacific

AIRS image of Tropical Storm Alma Credit: NASA/JPL
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At 9:00 a.m. EDT on Thursday, May 29, 2008, the National Hurricane Center (NHC) upgraded Tropical Depression 1-E to Tropical Storm Alma, and it is expected to become a hurricane before making landfall.

The NHC issued a special advisory as Alma quickly grew in strength, and new hurricane watches and warnings were posted for the west coast of Central America. Alma is now forecast to become a hurricane prior to making landfall.

The governments of Nicaragua and Honduras have issued hurricane warnings for the pacific coasts of their respective countries. A hurricane warning means that hurricane conditions are expected within the warning area, in this case within the next 12 hours.

At 9:00 a.m. PDT (12 noon EDT) Alma's center was located near latitude 11.7 north and longitude 86.9 west or about 50 miles (80 km) southwest of Managua, Nicaragua, and about 210 miles (335 km) southeast of San Salvador, El Salvador. Maximum sustained winds have increased to near 65 mph (100 Km/hr) with higher gusts. Alma could reach the coast as a hurricane.

Alma is moving toward the north near 7 mph (11 km/hr) and this general motion is expected to continue today. On this track Alma's center will reach the coast of Nicaragua tonight and be near the coasts of Honduras and El Salvador during the next day or so.

Torrential rains are expected to spread over portions of Panama, Costa Rica, Nicaragua and Honduras over the next few days. These rains could cause life-threatening flash floods and mud slides.

This infrared image of Alma was created on May 29 at 7:05 UTC (3:05 a.m. EDT) by data from the Atmospheric Infrared Sounder (AIRS), an instrument that flies aboard NASA's Aqua satellite.

This AIRS image shows the temperature of the cloud tops or the surface of the Earth in cloud-free regions. The lowest temperatures (in purple) are associated with high, cold cloud tops that make up the top of Alma (shown as the largest circular purple area west of Central America on this satellite image). The infrared signal of the AIRS instrument does not penetrate through clouds. Where there are no clouds the AIRS instrument reads the infrared signal from the surface of the Earth, revealing warmer temperatures (red).

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



May 29, 2008, first update

First Eastern Pacific Tropical Storm Forms Right After Season Starts

TRMM image of Tropical Depression 1e Credit: NASA/Hal Pierce
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Tropical Storm Alma formed only 13 days after the official start to the Eastern Pacific Hurricane Season, which is May 15. It formed around 8:00 p.m. PDT off the coast of Costa Rica on May 28.

At that time, meteorologists at the National Hurricane Center noted that an area of low pressure had organized enough to be called a tropical depression.

By 2:00 a.m. PDT (5:00 a.m. EDT), Tropical Depression (TD) One-E (as it was then called) was getting better organized with more "convective banding," or bands of rainfall around the center of the storm. Maximum sustained winds were near 30 knots (34 mph).

Alma was moving north-northwest near 4 knots (4 mph). The National Hurricane Center update notes "The new forecast calls for the center to make landfall in western Nicaragua in 18-24 hours." The forecast also calls for some gradual strengthening before landfall near the extreme northwestern tip of Nicaragua, and then weakening and dissipation over the mountains of Central America. It is expected to be over northwestern Honduras mid-day Friday, May 30.

Flooding rains are very likely as the system approaches and makes landfall. Flash floods and mud slides associated with heavy rains are expected especially in Costa Rica and Nicaragua, as rainfall totals could reach 20 inches.

The image was made from data captured by the Tropical Rainfall Measuring Mission (TRMM) satellite on May 29 at 0029 UTC (May 28 at 8:29 p.m. EDT). This TRMM image shows the horizontal pattern of rain intensity within Alma. The circular pattern is visible, and is surrounded by yellow and green areas, which indicate rainfall between 20 and 30 millimeters (.78 to 1.18 inches) per hour.

For more information about how TRMM looks at rainfall, visit NASA's TRMM Web site. TRMM is a joint mission between NASA and the Japanese space agency JAXA.

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