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Hurricane Season 2009: Tropical Storm Fred (Atlantic)
09.18.09
 
September 18, 2009

GOES-12 saw Fred's remnants almost 500 miles south of Bermuda earlier today, and it appears as a small circular area. > View larger image
GOES-12 saw Fred's remnants almost 500 miles south of Bermuda earlier today, September 18 at 7:31 a.m. EDT, and it appears as a small circular area.
Credit: NASA/GOES Project Fred's Remnants Nearing Bermuda

The remnants of former tropical storm Fred just won't quit. In fact, Fred's remnants have managed to make it across much of the Atlantic Ocean over the last week, and there's still a small chance he may "re-generate."

There's a small area of low pressure about 475 miles south of Bermuda that are associated with Fred's remnants. The low is moving westward between 10 and 15 mph, but it contains little shower activity today, September 19, according to the National Hurricane Center.

The Geostationary Operational Environmental Satellite, GOES-12 captured a visible image of Fred's remnants almost 500 miles south of Bermuda earlier today, September 18 at 7:31 a.m. EDT, and it appears as a small circular area. GOES is operated by the National Oceanic and Atmospheric Administration, and NASA's GOES Project, located at NASA's Goddard Space Flight Center, Greenbelt, Md. creates some of the GOES satellite images.

It seems that the environment still isn't cooperating to assist Fred in re-forming. Upper-level winds are strong enough to deny any opportunities for circulation. Despite the winds not cooperating, the National Hurricane Center says that there's "less than a 30 percent chance" that the system will re-generate into a tropical cyclone over the next 48 hours. Meanwhile, Fred's remnants will continue on their westward track over the weekend.

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


September 16, 2009

The AIRS instrument captured this visible image that appear to resemble a tilted exclamation point. > View larger image
NASA's Aqua satellite flew over Fred's remnants on September 13 at 1:35 p.m. EDT and the AIRS instrument captured this visible image that appear to resemble a tilted exclamation point.
Credit: NASA/JPL, Ed Olsen
 Fred's Remnants Still Moving Through the Atlantic

The remnants of the once mighty Hurricane Fred continue to move through the central Atlantic Ocean today, Wednesday, September 16. The National Hurricane Center in Miami, Fla. noted that Fred's remnants continue to produce intermittent showers and thunderstorms, but the environment around Fred is not cooperating to allow them redevelop into a tropical cyclone. In fact, the National Hurricane Center gives Fred's remnants less than a 30 percent chance of a rebirth. Fred's remnants are located about 650 miles east-northeast of the Northern Leeward Islands today, and are moving west-northwest at about 15 mph. If Fred does re-generate, he'll likely keep his name.

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





September 14, 2009

The AIRS instrument captured this visible image that appear to resemble a tilted exclamation point. > View larger image
NASA's Aqua satellite flew over Fred's remnants on September 13 at 1:35 p.m. EDT and the AIRS instrument captured this visible image that appear to resemble a tilted exclamation point.
Credit: NASA/JPL, Ed Olsen
 Fred Fades with a Satellite Exclamation Point

NASA's Aqua satellite flew over the remnants of Fred, September 13 and captured a visible image of the storm's clouds from the Atmospheric Infrared Sounder (AIRS) instrument. The AIRS image showed Fred's clouds stretched from northeast to southwest. The remnants resembled a tilted exclamation mark.

During the morning hours of Monday, September 14, the remnants of Fred were located about 900 miles west of the northernmost Cape Verde islands. Associated shower and thunderstorm activity remains limited...and upper-level winds are expected to remain unfavorable for re-development.

On Saturday, September 12, the National Hurricane Center (NHC) declared that Fred was indeed "dead" as a tropical cyclone. At 5 p.m. EDT that day the NHC discussion said "There has been no central convection associated with Fred since about 0000 UTC (8 p.m. EDT on Friday, September 11) and Fred is no longer classifiable using the Dvorak technique. The lack of deep convection also means that Fred is no longer a tropical cyclone and is now declared a remnant low pressure area." The NHC used data from NASA's QuikScat instrument (on the SeaWinds satellite) to determine that Fred's circulation had weakened to that point.

As of this morning, Monday, September 14, the NHC said that Fred's remnants may continue to produce intermittent shower and thunderstorm activity as it moves west-northwestward at 10 to 15 mph over the next couple of days. The Hurricane Center said that there's a small chance it may re-organize into a tropical cyclone during the next 48 hours… but it's just that: a small chance.

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


September 11, 2009

The purple area in Fred's center revealed the strongest winds. Wind direction is indicated by small barbs. > View larger image
NASA's QuikScat used microwave technology to capture an image of Fred's 80 mph surface winds September 11 at 6:53 a.m. EDT. The purple area in Fred's center revealed the strongest winds. Wind direction is indicated by small barbs. White barbs point to areas of heavy rain.
Credit: NASA/JPL, Peter Falcon
 Fred Creeping Into Hostile Territory, Already Waning

Hurricane Fred is in for a beating this weekend, and environmental factors are his nemesis. The National Hurricane Center noted that even his cloud pattern has been "gradually deteriorating since yesterday and has become even more elongated due to [wind] shear." NASA's QuikScat satellite took a flight over Fred earlier today, September 11 and revealed his winds had dropped to category one hurricane strength.

At 11 a.m. EDT, the once-mighty Fred had maximum sustained winds near 80 mph, and he was creeping northward near 1 mph. His center was located near latitude 18.0 north and longitude 35.0 west or about 740 miles west-northwest of the Cape Verde Islands. Estimated minimum central pressure is 983 millibars.

The National Hurricane Center noted in their discussion this morning, "Water vapor images show massive upper-level westerly and southwesterly flow from the Caribbean eastward across the tropical Atlantic associated with a stronger than normal mid-oceanic trough (elongated area of low pressure). It is highly unlikely that Fred will survive such hostile upper-level environment. "

NASA’s QuikScat satellite captured a view of Hurricane Fred on September 11, 2009, shortly after 11 a.m. EDT. QuikScat captured the wind structure of the storm. This morning, the National Hurricane Center noted, "The initial intensity has been lowered to 70 knots based on 4.0 and 4.5 dvorak t-numbers from SAB and TAFB and a Quikscat pass over the cyclone earlier today."

The Tropical Analysis and Forecast Branch (TAFB) is a group of highly trained meteorologists who specialize in marine meteorology, tropical meteorology, satellite imagery interpretation, and tropical weather analysis. As an integral part of the National Hurricane Center (NHC), the TAFB performs forecasting, outreach, and support functions. NOAA also has forecasters that work at the Satellite Analysis Branch (SAB) who support the NHC.

QuikScat is a scatterometer on the NASA SeaWinds satellite that measures wind speed by bouncing microwave pulses off the ocean’s surface and recording the echo. An ocean tossed by strong winds will scatter the energy differently than a calm ocean, so the measurement provides an indication of both wind speed and direction. Since hurricanes are relatively rare, scientists have not calibrated the data to accurately report wind speeds greater than 50 knots (about 60 miles per hour). Heavy rain also distorts the ocean’s surface, making wind speeds more difficult to gauge.

Fred is embedded within very light steering currents. Steering currents are winds aloft in the atmosphere that can push a tropical cyclone. Computer models keep whatever is left of Fred meandering for the next two days before starting him on a westward track.

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


September 10, 2009

The AIRS instrument provided valuable infrared data on Fred's cloud top temperatures, indicating some strong thunderstorms. > View larger image
The Aqua satellite also flew over Hurricane Fred earlier today, September 10 at 12:11 a.m. EDT and the AIRS instrument provided valuable infrared data on his cloud top temperatures, indicating some strong thunderstorms.
Credit: NASA/JPL, Ed Olsen
 NASA Sees Hurricane Fred Moving Northwest

Fred's winds have diminished, and he's still on a journey northwest keeping to the eastern Atlantic Ocean and far from land. NASA's Aqua satellite captured an image of Fred as his thunderstorms are weakening and his winds are starting to wane.

Hurricane Fred's maximum sustained winds are now near 100 mph and they're expected to continue weakening as Fred moves into cooler waters on his northern route in the Atlantic Ocean. At 11 a.m. EDT today, September 10, Fred was 740 miles west of the Cape Verde Islands, near 16.8 north and 35.1 west. He's moving northwest near 7 mph, and has a minimum central pressure near 974 millibars.

The Aqua satellite also flew over Hurricane Fred this morning at 12:11 a.m. EDT and the Atmospheric Infrared Sounder (AIRS) instrument provided valuable infrared data on his cloud top temperatures. They're important because they tell forecasters how high thunderstorms are, and the higher the thunderstorm, the more powerful it is, and the data helped forecasters see Fred's cloud tops were as cold as or colder than minus 63 degrees Fahrenheit (F).

In addition to the infrared imagery, AIRS also provides visible images, and the visible satellite imagery showed Fred still had an eye, even though it's not a clear as it was yesterday. The National Hurricane Center said that Fred's cloud pattern has become a little bit elongated due to southerly shear that is beginning to affect the hurricane.

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


September 9, 2009

NASA's MODIS instrument on the Terra satellite captured Hurricane Fred in the central Atlantic Ocean. > View larger image
NASA's MODIS instrument on the Terra satellite captured Hurricane Fred in the central Atlantic Ocean earlier today, September 9. MODIS showed that Fred has a well-developed eye, and at present he's a major hurricane at Category Three status.
Credit: NASA, MODIS Rapid Response
Microwave images are created when data from NASA's Aqua satellite AIRS and AMSU instruments are combined. > View larger image
Microwave images are created when data from NASA's Aqua satellite AIRS and AMSU instruments are combined. The cold areas in this image (yellow-green) indicates where there is precipitation or ice in the cloud tops. The microwave image suggests cold, high thunderstorms.
Credit: NASA/JPL, Ed Olsen
NASA's QuikScat satellite captured Hurricane Fred's winds using its microwave imagery to peer through its clouds. > View larger image
NASA's QuikScat satellite captured Hurricane Fred's winds using its microwave imagery to peer through its clouds September 9 at 3:42 a.m. EDT). The strongest winds are represented in the center of circulation in the purple area, which are about120 mph. White barbs point to heavy rain near Fred's center.
Credit: NASA/JPL, Peter Falcon
 3 NASA Satellites See Fred Become Second Major Hurricane in Atlantic

Three NASA satellites had Fred in their sights when he became a major hurricane. QuikScat eyed his winds, Terra eyed his cloud cover, and Aqua eyed his cloud temperature, ice and precipitation.

At 11 a.m. EDT today, September 9, Hurricane Fred strengthened to a category three hurricane on the Saffir-Simpson Scale. That gives Fred the title of the "second major hurricane of the Atlantic Ocean season."

Fred however poses no threat to land, as he's far in the eastern Atlantic Ocean. In fact, Fred is 540 miles west of the southern-most Cape Verde Islands (off the coast of Africa). He's near 13.9 north and 32.4 west. His maximum sustained winds are near 120 mph, but he's moving northwest and into cooler waters, meaning he'll start to weaken. His minimum central pressure is 958 millibars.

NASA's Aqua satellite flew over Fred, and the Atmospheric Infrared Sounder (AIRS) instrument onboard captured infrared, visible and microwave imagery of the hurricane.

Infrared imagery measures temperatures and not only can it see cold, high cloud tops in tropical cyclones, but also the warm ocean waters that power the cyclones (if the sea surface temperatures are over 80F). Cold cloud top temperatures provide clues about the power of the thunderstorms in a tropical cyclone. The colder the clouds are, the higher they are, and the more powerful the thunderstorms are that make up the cyclone. Fred's cloud temperatures were colder than minus 63 Fahrenheit, indicating very cold, high, strong thunderstorms within. The ocean waters beneath Fred are also over 80F, but as he tracks farther north, those temperatures will decline.

AIRS data is also coupled with data from the Advanced Microwave Sounding Unit (AMSU) that flies with AIRS on Aqua to create microwave images of storms. The AMSU image uses the radiances of the 89 GHz channel, and the cold areas in those images indicate where there is precipitation or ice in the cloud tops.

NASA's Terra satellite also flew over Fred earlier today, September 9 at 8:55 a.m. EDT, and using the Moderate Imaging Spectroradiometer (MODIS) instrument captured an image of the storm that clearly shows Fred's eye in the center of circulation.

Like the Aqua and Terra satellites, NASA's QuikScat satellite captures data from tropical cyclones. QuikScat reads the rotating surface wind speeds of tropical cyclones using its microwave imagery to peer through their clouds. QuikScat data are used to make images that show wind speeds in different colors and wind direction are indicated by small barbs. QuikScat today revealed Fred's highest winds in the center were near 120 mph.

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












September 8, 2009

TRMM satellite captured Fred's moderate rainfall (in red) when it flew overhead on September 7 at 7:23 p.m. EDT. > View larger image
The TRMM satellite captured Fred's moderate rainfall (in red) when it flew overhead on September 7 at 7:23 p.m. EDT. At that time, Fred was the seventh Atlantic Tropical depression.
Credit: NASA/SSAI, Hal Pierce
> Click here to see a 3-D animation of Fred's towering thunderstorms and rainfall
 NASA Sees Tropical Storm Fred's Moderate Rains in 3-D

The seventh tropical depression in the Atlantic Ocean was born yesterday at around 5 a.m. EDT, 160 miles south of the southernmost Cape Verde Islands and strengthened into Tropical Storm Fred by 11 p.m. EDT that night. NASA's Tropical Rainfall Measuring Mission (TRMM) satellite captured its rainfall as it just before the depression strengthened into a tropical storm.

Fred is the sixth named storm in the Atlantic Season, as one tropical depression never strengthened to get a name.

The TRMM satellite, a joint mission between NASA and JAXA, the Japanese Space Agency, flew over Fred when he was a tropical depression and captured his rainfall rates. Scientists at NASA use TRMM data to create a 3-D look at the storm's cloud heights and rainfall, which is extremely helpful in forecasting.

"One of the interesting capabilities of the TRMM satellite is its ability to see through clouds with its Precipitation Radar (PR) and reveal the 3-D structure within storms such as Tropical Storm Fred," said Hal Pierce, on the TRMM mission team in the Mesoscale Atmospheric Processes Branch at NASA's Goddard Space Flight Center, Greenbelt, Md.

Pierce created a 3-D image of Fred. He used data captured on September 7 when TRMM also got a "top down" view of the storm's rainfall, and created a 3-D image that shows thunderstorm tops. TRMM data revealed rainfall between 20 and 40 millimeters (.78 to 1.57 inches) per hour within the storm.

At 11 a.m. EDT today, September 8, Fred's maximum sustained winds were near 65 mph, and he's expected to strengthen into a hurricane later today. He was located at sea, 345 miles southwest of the southernmost Cape Verde Islands near 11.9 north and 28.6 west. He was moving west near 14 mph and had a minimum central pressure of 994 millibars.

Fred is predicted by the National Hurricane Center (NHC) in Miami, Florida to continue gaining strength and become a minimal hurricane with wind speeds of 65 knots (~75 mph) later today. Fred isn't expected to pose much danger because it is predicted to re-curve into the open Atlantic Ocean west of the Cape Verde Islands.

Text credit: Rob Gutro, NASA/Goddard Space Flight Center and Hal Pierce, SSAI/Goddard Space Flight Center
 
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