Tropical Storm Arlene was the first named storm of the 1999 Atlantic hurricane season. Arlene formed in the Atlantic well to the southeast of Bermuda on June 11. It moved northeast, west-northwest, and then eventually back to the northeast, reaching its peak of 60 mph as it did so, and then dissipated on June 18.
Arlene caused no damage or deaths.
|Formation||June 11, 1999|
|Dissipation||June 18, 1999|
|Highest winds||60 mph|
|Lowest pressure||1006 mbar|
The complex development of Arlene can be traced to a mid to upper-level cold low that developed near the tail end of a diffuse front in the central Atlantic Ocean. Water vapor imagery first noted the circulation of the upper-level low located a few hundred miles north of Puerto Rico on June 8. At the same time, a fairly large-amplitude tropical wave through the tail end of the front that was located southeast of the upper-level low, and a low-level cloud swirl became visible near 22°N 61°W, close to the wave axis, and to the southeast of the upper-level low. The low-level cloud swirl moved slowly northwest over the Atlantic Ocean for the next 2 days without development, due to westerly wind shear from the upper-level low. Throughout this period, generally steady convection had been maintained in the diffluence region to the east of the upper-level low. By 0600 UTC on June 10, the low-level circulation moved underneath the cold-cored low, near 24°N 63°W. Shortly thereafter, the upper-level low began to move eastward into the convective area.
As the upper-level accelerated rapidly to the northeast on June 10, satellite microwave imagery revealed the rapid downward development of a vortex within the convection, which led to the formation of a new low-level circulation center. During the morning of June 11, the convection acquired enough banding features to be classified as Tropical Depression One at 1800 UTC on June 11, while located about 465 miles southeast of the island of Bermuda. The original low-level cloud swirl moved off to the west, eventually dissipating. Almost immediately after becoming a depression, the storm's foward speed decreased, and it began to drift to the north for 24 hours. By 1200 UTC on June 12, the depression is estimated to have reached tropical storm status, becoming Tropical Storm Arlene. Arlene intensified for 12 hours before wind shear exposed the low-level circulation center. Arlene reached its peak intensity of 60 mph at 0000 UTC on June 13. During this time the pressure was estimated at 1006 mb, unusually high for a tropical cyclone of this intensity.
Arlene moved generally west-northwest from June 13 to June 15, also slightly weakening as it did so, because of strong vertical shear. Because steering currents collapsed, Arlene showed very little movement on June 15. Arlene preformed a small cyclonic loop. Late on June 15, a northwesterly motion resumed, followed by a gradual turn to the north, then northeast over the next three days as Arlene moved around the western edge of the subtropical ridge. Arlene passed as close to land as it would throughout its entire life when it passed 100 miles east of Bermuda on June 17. On June 16, convection with Arlene began to decay, with northeasterly shear affecting Arlene, and also cooler water temperatures. Synoptic-scale upper-level confluence and subsidence in the immediate environment of Arlene, which caused supressed convective activity. At 0000 UTC on June 17, Arlene weakened to a tropical depression, and Arlene dissipated ahead of an approaching frontal boundary on June 18.
Tropical Storm Watches were issued for Bermuda just incase Arlene were to come near. Arlene passed to the east of Bermuda fortunately, thus no significant weather impacts were observed in Bermuda.
Lack of Retirement
Because of no damage, Arlene was not retired in the Spring of 2000 by the World Meteorological Organization, and it was used again in the 2005 Atlantic hurricane season, and was not retired there either. It is therefore on the list of names to be used for the 2011 Atlantic hurricane season.