Preliminary Report
Hurricane Tanya
27 October - 03 November 1995

1995 PRELIMINARY REPORTS

Hurricane Allison (1)
Tropical Storm Barry (TS)
Tropical Storm Chantal (TS)
Tropical Storm Dean (TS)
Hurricane Erin (2)
Hurricane Felix (4)
Tropical Storm Gabrielle (TS)
Hurricane Humberto (2)
Hurricane Iris (2)
Tropical Storm Jerry (TS)
Tropical Storm Karen (TS)
Hurricane Luis (4)
Hurricane Marilyn (3)
Hurricane Noel (1)
Hurricane Opal (4)
Tropical Storm Pablo (TS)
Hurricane Roxanne (3)
Tropical Storm Sebastien (TS)
Hurricane Tanya (1)

Tanya caused gale force winds over the Azores, while losing its tropical characteristics.

 

a. Synoptic History

Tanya originated from a tropical wave that, based on extrapolation, moved off the west coast of Africa in mid-October. This wave followed one that spawned Tropical Storm Sebastien, and was not easily identifiable as a cloud mass on satellite pictures until 20 October, when it neared 40°W longitude in the tropical Atlantic. The wave moved slowly westward for a few days. By 24 October, cloudiness associated with the wave merged with an area of convection to the east and northeast of Tropical Depression Sebastien. This weather was partly associated with an upper-level cyclone that was producing shearing winds over Sebastien, causing its demise. At 1800 UTC on the 25th, a low cloud swirl was evident in the vicinity of 22°N 60°W. However, this system was barely classifiable by the Dvorak technique since deep convection was not very close to the center. The low-cloud swirl became more pronounced on satellite images on the 26th. By 0000 UTC 27 October, surface observations indicated a definite closed surface circulation, and the tropical depression stage of Tanya is initiated at this time in the post-analysis best track.

The movement of the tropical cyclone was controlled mainly by two factors: shortwaves in the midlatitude westerlies and the upper-level cyclone in Tanya's vicinity. Initially the cyclone moved northeastward, in response to an approaching shortwave trough. However, due to the effect of the upper cyclone, Tanya turned more eastward and slowed.

Because of the influence of the upper-level cyclone, the development of Tanya was not like that of a typical tropical cyclone in the deep tropics. On the 27th and 28th, the system had some subtropical characteristics, i.e. a large comma-shaped cloud band and strongest winds well removed from the center. Nonetheless, Tanya's winds increased to tropical storm force by 1200 UTC on the 27th and gradual strengthening continued thereafter. Convection developed closer to the center by 1800 UTC on the 28th, and on the following day the cloud pattern was more symmetrical about the center. Tanya reached hurricane strength around 1200 UTC on the 29th, when a small eye was observed in the middle of the central dense overcast.

While Tanya was strengthening into a hurricane, its motion was cyclonic along roughly a half-circular path, again due to the adjacent upper low. This movement continued into the 29th, when a strong eastward-moving mid-tropospheric trough over the western Atlantic, and associated cold front near Bermuda, began to influence the track of the hurricane. Tanya turned north- northeastward on the 30th, and east-northeastward later that same day. Early on the 31st, while still embedded in a narrow wedge of warmer air between cooler air masses over the western and eastern Atlantic, the system acquired peak intensity of 86-mph winds with a 972 mb central pressure.

On the 1st of November, Tanya veered to the east and weakened to a tropical storm - headed in the general direction of the Azores. As the storm neared those islands, the movement became more northeasterly, taking the center just to the north of the Azores. Tanya was becoming extratropical as it passed near the Azores. The extratropical cyclone turned north-northeastward, then northward, and was absorbed into a larger low pressure system over the north Atlantic by 0600 3 November.

b. Meteorological Statistics

There were some surface observations from the Azores of sustained gale force winds. Lajes Air Base on Terceira measured sustained winds of 39 mph at 2255 UTC with gusts to 68 mph at 2343 UTC on the 1st. Santa Maria Island reported sustained winds of 45 mph at 2300 UTC on the 1st, with gusts to 58 mph at 0200 UTC on the 2nd. Lowest pressure observed in the Azores was 973.5 mb at Horta on the island of Faial.

One ship, with call sign GBSA, had the misfortune of being near the center of Tanya twice: on the 29th, when Tanya was a hurricane; and on the 2nd, when Tanya was an extratropical storm.

c. Casualty and Damage Statistics

Although strong winds likely had some impact on the Azores and ships that were affected by Tanya, no reports of casualties or damage have been received at the NHC.