a. Synoptic History
Tropical Storm Grace developed from one of several lows that
developed along a frontal trough extending east-northeastward from the
western Caribbean Sea to the central North Atlantic Ocean. Surface observations
indicate that the extratropical low that became Grace was initially centered
just north of Hispaniola, and that it reached gale strength near 0000
UTC on 15 October. One day later, a large area of deep convection developed
over or just northeast of the low-level circulation center. This is the
basis for indicating in the post-storm "best track" that the system transformed
into a tropical cyclone at 0000 UTC on the 16th. The system did not shed
all of its extratropical characteristics, however. Most notably, the circulation
remained elongated along the frontal trough and a band of deep convection
appeared to link Grace to another low-pressure center with gale-force
winds that was located about 500 nautical miles to the east-northeast.
Grace developed in an environment of southwesterly vertical
wind shear generally to the south of a large extratropical cyclone south
of Newfoundland. The associated steering currents accelerated Grace to
about 29 mph on an east-northeast to northeast heading. The limited
available ship reports and intensity estimates based on satellite pictures
suggest that Grace was at its strongest, with 46 mph winds, at the time
that it became a tropical cyclone. The storm appeared to slowly weaken
thereafter and, on the morning of the 17th, deep convection dissipated.
This revealed a weak and diffuse low-level circulation that, over the
course of about a day, became indistinguishable from the frontal trough
in which it was embedded.
b. Meteorological Statistics
Position and intensity estimates were obtained from analyses
of satellite pictures by NOAA's Synoptic Analysis Branch (SAB) and Tropical
Analysis and Forecast Branch (TAFB), and by the Air Force Global Weather
Center (AFGWC). The analyses also included surface observations.
There were no observations of tropical storm force winds
associated with the tropical cyclone phase of Grace.
c. Casualty and Damage Statistics
Grace did not directly affect land and no reports of casualties or damages were received.
Intensity For Tropical Storm Grace