a. Synoptic History
The frontal system that swept Hurricane Bill
northeastward across the western Atlantic also generated a frontal low a few
hundred miles to the east of Georgia and South Carolina on 11 July. Over
the following two days the low moved little and gradually acquired
a closed, low-level circulation that was independent of the frontal
band dissipating in its vicinity. The low is estimated to have
become a tropical depression at
0600 UTC on the 13th (Fig. 1 [24K GIF] and
Table 1), while located about 275
nautical miles to the south-southeast of Cape Hatteras, North Carolina.
The depression became Tropical Storm
Claudette 12 hours later, based on 45-50 knot winds measured
at a flight level of 750 ft during the first reconnaissance aircraft mission in the
system. About this time, banding of convection increased enough for
Dvorak T-numbers to reach 2.5. This development came
despite some southerly to southwesterly wind shear which prevented Claudette
from developing more than a weak anticyclone aloft.
Deep convection was episodic with most activity occurring during
the night hours. Satellite classifications and aircraft data
suggest that Claudette retained 30-40 kt winds from the 13th-16th.
During that period, Claudette initially moved northward, but then
was accelerated toward the east by the flow ahead of an approaching
frontal system. On the 16th, Claudette merged with the front, its
center once again becoming a frontal low. The extratropical low
moved generally toward the east over the following week. Satellite
pictures suggest that it dissipated near the Azores Islands on the
b. Meteorological Statistics
The post-storm "best track"
(Table 1) was obtained from the
data presented in Figs. 2 (20K GIF) and
3 (27K GIF). Those figures show Claudette's
estimated central pressure and maximum one-minute wind speed,
respectively, versus time. 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 observations from the reconnaissance aircraft flights taken by the
Air Force Reserve.
There were no land, ship or buoy reports of tropical storm force
winds associated with Claudette.
c. Casualty and Damage Statistics
Claudette did not directly affect land and no reports of casualties
or damages were received.
d. Forecast and Warning Critique
Claudette was a tropical storm for 60 hours. This is too
short a period to provide a meaningful quantitative evaluation of forecast
accuracy. Qualitatively, the NHC and guidance forecast tracks
generally resembled the observed track. The NHC intensity
forecasts indicated a little more strengthening than what
Hurricane and tropical storm watches and warnings were neither
issued nor necessary.