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Posted at 12:30 PM ET, 10/03/2012

Nadine joins rank of Atlantic longest-lived storms; tropical depression 15 forms

Tropical Storm Nadine and the Azores islands. (UW/CIMSS)
Tropical storm Nadine began as tropical depression on September 11, and has been a numbered system for 21 days as of 11 a.m. today. That extreme duration has earned Nadine a spot among the top-five longest-lived tropical cyclones in Atlantic history going back to 1851.

This morning, it’s tied for fifth place with hurricane #4 in 1926, and is lagging behind hurricane Kyle (2002) at 22 days, hurricane Inga (1969) at 24.75 days, hurricane Ginger (1971) at 27.25 days, and finally, hurricane #3 (1899) at 28 days. However, using the latest official National Hurricane Center forecast, Nadine is expected to remain a tropical entity for another 1.25 days, and if that verifies, Nadine would jump into fourth place.

At the 11 a.m. advisory, Nadine is a weakening tropical storm with 50 mph maximum sustained winds, and is located about 405 miles west-southwest of the Azores islands. It’s falling apart quickly now, and would need a miracle if it’s going to come back for another encore.

A recent satellite image (above) shows an exposed low-level circulation (I marked the center with a red L) and the colder (whiter) cloud tops associated with strong thunderstorms are all located to the east and south of the storm’s center.

New tropical depression: TD15

Visible satellite image of AL96. (NRL-Monterey)
A disturbance in the central Atlantic that began as an easterly wave off the African coast a week ago has been classified tropical depression (TD) 15 as of 11 a.m. today. The embedded 29.77” (1008mb) low pressure is centered 1160 miles west of the Cape Verde islands and moving northwest, VERY far from land.

Models are in excellent agreement that this disturbance will become tropical storm Oscar very soon. The track forecasts take it north a little further, then recurve it to the northeast, passing near or over the Azores this weekend.

GOES-East update

On Monday morning, the decision was made within NOAA to begin moving GOES-14 eastward to replace the GOES-13 satellite that suffered significant instrument anomalies on September 23. While engineers are still working to repair GOES-13, it’s possible that it might not be fixable.

Schematic drawing of the positions of NOAA’s three operational geosynchronous satellites and their respective fields of view.
As a refresher, these geosynchronous satellites orbit the globe at a fixed location, giving us the continuous satellite images and loops that you routinely see on television and the internet. This unique orbit requires that they are positioned exactly over the equator and at 22,236 miles above the Earth’s surface. The longitude that it’s “parked” over determines the field of view it will have, as illustrated in this figure (not to scale).

GOES-15 is situated over 135W to provide coverage for the eastern Pacific and western U.S., GOES-13 is situated over 75W to provide coverage of the western Atlantic and eastern US, and GOES-14 has been in orbit as a spare and is situated at 105W (between the others in case one of them should fail). Beginning this past Monday, GOES-14 is being manuevered eastward at a rate of 0.9 degrees/day, which would bring it to 75W by November 3, if GOES-13 isn’t repaired by then.

* Brian McNoldy is a senior researcher at the University of Miami’s Rosenstiel School of Marine and Atmospheric Science.

By Brian McNoldy  |  12:30 PM ET, 10/03/2012

Categories:  Latest, Tropical Weather

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