Tropical Storm Gabrielle Disorganized in Eastern Atlantic

At 5:00 AM AST, the center of Tropical Storm Gabrielle was located near latitude 21.9 North, longitude 35.0 West. Gabrielle is moving toward the northwest near 13 KM/H, and this motion is expected to continue for the next few days with an increase in forward speed.

Tropical Storm Gabrielle became the seventh named storm of the 2019 Atlantic Hurricane Season on Tuesday.

Maximum sustained winds remain near 85 KM/H with higher gusts. Little change in strength is forecast during the next couple of days. Afterward, some slow strengthening is expected to begin by this weekend.

Tropical-storm-force winds extend outward up to 260 kilometers from the center.

The estimated minimum central pressure is 1002 millibars.

Discussion

There are no watches or warnings in effect.

METEOSAT imagery and an earlier WindSat microwave overpass show Tropical Storm Gabielle’s poorly defined center of circulation sheared well to the south of the curved convective band features to north, indicative of moderate southerly shear. The initial intensity is held at a generous 45 kt for this advisory, and is based on the subjective T-numbers from TAFB and SAB.

Although Gabrielle could experience some intensity fluctuations during the next 24 hours, the cyclone should remain in a rather harsh environment during the next 36-48 hours, due to south to southwesterly vertical shear, some dry air in the middle portions of the atmosphere, and oceanic sea surface temperatures on the order of 25-26C.

Afterward, gradual strengthening is forecast as Tropical Storm Gabrielle moves into a more favorable upper wind pattern and warmer SSTs, and this is consistent with the IVCN multi-model consensus and the Decay SHIPS.

After the adjustment to the south of the previous advisory based on the ASCAT-A/B scatterometer passes and a recent SSMI/S image, the initial motion is estimated to be northwestward, or 315/7 kt.

For the next several days, Gabrielle is expected to move generally northwestward toward a large weakness in the mid-Atlantic subtropical ridge. An increase in forward motion is expected as the steering flow strengthens between a cut-off low to the west and high pressure to the northeast.

Around days 4 and 5, the cyclone should turn generally northward in response to an approaching mid-tropospheric short wave trough. An adjustment to the right of the previous forecast was made, and the NHC forecast is based on a blend of the various consensus models.

Hazards Affecting Land

There are no hazards affecting land.


Tropical Storm Gabrielle is of no threat to the Lesser Antilles, including Trinidad and Tobago.

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