This hurricane originated on October 4 near Barbados as a " cyclonic perturbation "; however, no closed circulation was evidently associated with the system.
12.
BD was launched in 1970 by publisher Morgan Grampian as a closed circulation weekly as high-tech architecture was just starting to take-off.
13.
After a reconnaissance aircraft flight failed to locate a closed circulation, the system dissipated late on November 7, while located about south-southeast of Bermuda.
14.
If a tropical wave is moving quickly, it can have strong winds of over tropical storm force, but is not considered a tropical storm unless it has a closed circulation.
15.
Despite lacking a closed circulation, the overall structure remained well-organized, and with a favorable upper-level environment the possibility of regeneration into a tropical cyclone was noted.
16.
Also, a scatterometer pass near 0500 UTC on the 23rd indicated an open wave with no closed circulation, which justifies the official decision not to treat Chanchu as the continuation of Upana.
17.
During this period, the Great Whirl almost forms a closed circulation, and strong upwelling streams ( colder than 17 �C, typical upwelling water temperature ~ 19-23 �C ) develop near the Northern Somali coast.
18.
This prohibited the application of his theory to the western boundary currents, since some form of dissipative effect ( bottom Ekman layer ) would be later shown to be necessary to predict a closed circulation for an entire ocean basin and to counteract the wind-driven flow.
19.
Early on July 8, additional data from the Hurricane Hunters indicated that the system developed a closed circulation and the NHC classified it as a tropical depression at 0000 Hydrometeorological Prediction Center ( HPC ) issued advisories until it dissipated early on July 10, over northern Mexico.
20.
This caused the structure to deteriorate, and on August 9 Bret weakened to tropical depression status with the circulation " practically dissipated ", according to the NHC . The Hurricane Hunters had difficulty finding a closed circulation, prompting the NHC to discontinue advisories at 15 : 00 UTC on August 9.
