Linda is estimated to have been the strongest
hurricane on record in the
eastern North Pacific Ocean.
With the exception of Socorro Island, Linda did not directly affect land,
although long-range computer models indicated that the
tropical cyclone would approach southern California.
a. Synoptic History
Rawinsonde data from Dakar indicated that a well-defined
tropical wave emerged
from the west coast of Africa on 24 August. The wave was tracked across the
Atlantic and the Caribbean Sea in satellite imagery. Increased cloudiness and
convection off the Pacific coast of Panama on 6 September was likely associated
with the wave. Evidence of a poorly-defined cloud system
center within a broad
appeared in satellite imagery early on 9 September. A banding-type
pattern emerged, and the "best track"
indicates that a tropical depression formed
from the disturbance near 1200 UTC 9 September while centered about 400 n mi
south of Manzanillo, Mexico (Fig. 1 (19K GIF) and
Table 1). The tropical cyclone moved
northwestward at 5 to 10 knots, partly in response to a mid- to upper-level
low in the vicinity of lower Baja California.
Deep convective banding increased and the depression strengthened
into Tropical Storm Linda at 0000 UTC
10 September while centered about 350 n mi south-southwest of Manzanillo.
Upper-level outflow became very well established and
intermittent hints of an eye
appeared by 0000 UTC 11 September, at which time Linda is estimated to have
become a hurricane while centered about 475 n mi south-southeast of the southern
tip of Baja California. Rapid strengthening occurred and it is estimated that
Linda reached its peak intensity with 160 knot winds and 902 mb
minimum central pressure near 0600 UTC 12 September while centered about 125
n mi southeast of Socorro Island. A small, well-defined eye embedded within very
cold convective tops was visible on satellite imagery at this time.
On 13 September, Linda began moving toward the west-northwest at 10 to 12 knots
in response to a building ridge to the north of the tropical cyclone.
Linda moved over cooler water and weakened to a tropical storm by 1200 UTC 15
September while centered about 730 n mi west of the southern tip of Baja California.
Steering currents also began weakening about this time, and the forward motion
gradually decreased to near 5 knots. Linda weakened to a tropical depression by
0600 UTC 17 September while centered about 960 n mi west of the southern tip of
Baja California and dissipated by 0000 UTC 18 September, although a weakening
swirl of mostly low clouds persisted for a few more days.
b. Meteorological Statistics
Figures 2 (22K GIF) and
3 (24K GIF) show the curves of minimum
central pressure and maximum one-minute wind speed, respectively,
versus time along with the observations on which they are based.
As usual for an eastern Pacific tropical cyclone, satellites provided
the primary source of observational data. Formal
Dvorak technique location and
intensity estimates from the satellite data were produced by the
Air Force Global
Weather Center (AFGWC), the NOAA
Synoptic Analysis Branch (SAB) and the
NOAA Tropical Analysis and Forecast Branch (TAFB). In addition to the formal
Dvorak estimates shown in Figs. 2 and 3,
objective Dvorak T-numbers (based on the warm spot eye temperature and the coldest surrounding
ring temperature at a radius of 30 n mi from the center) were calculated by TAFB at 30 minute intervals.
All of these objective Dvorak T-numbers were between 7.5 (155 knots)
and 8.0 (170 knots)
from 0000 UTC 12 September to 1200 UTC 12 September, and is the justification for
overriding some of the intensity constraints of the Dvorak technique. The
highest 3-hour average objective T-numbers were 7.8 ending at 0430 UTC and 7.7 ending at
0600 UTC on 12 September. The peak intensity of Linda, estimated to have occurred
near 0600 UTC 12 September, is a conservative estimate that is higher than normal
Dvorak constraints would allow, but somewhat lower than objective T-numbers
would suggest possible. Although maximum sustained winds of 160 knots
and minimum central pressure of 902 mb indicated in the best track makes Linda the
strongest hurricane on record in the eastern North Pacific to date, one should
remember that intensities are almost always estimated from satellite interpretations
for this basin. Also, the record is quite short, since routine satellite surveillance
began in 1966. There could well have been other cyclones
as strong as, or stronger than, Linda.
In addition to the satellite information on Linda, the
NOAA high-altitude jet flew
synoptic-flow dropwindsonde missions which resulted in data being available for the
0000 UTC NCEP global model runs on the 14th and 15th.
The intent of these missions was to provide the most accurate description of the steering flow in the
environment around Linda during the period just prior to potential recurvature.
Evaluations of the impact of these missions will be made by NCEP.
Four vortex messages were provided from a U.S. Air Force Reserve
aircraft on 14 September,
after Linda had peaked in intensity.
The eye of Linda passed very near Socorro Island near 1800 UTC 12 September, but
unfortunately power was cut off to all wind and pressure recording instruments.
c. Casualty and Damage Statistics
There were no reports of casualties or damage from Linda received at the National
Hurricane Center. CNN reported five men swept off a jetty in Newport Beach,
California by large waves related to Linda. All were rescued.
d. Forecast and Warning Critique
NHC average official track forecast errors (excluding the tropical depression stage)
were 32 (27 cases), 73 (25 cases), 117 (23 cases), 163 (21 cases) and 247 n. mi. (17
cases), respectively, for the 12-, 24-, 36-, 48- and 72-hour forecast periods. These
average errors were higher than the 1988-1996 average errors at the 36-, 48- and 72-hour
forecast periods and were about the same at other times. The NHC average
official track forecast errors were higher than the averages from the operationally
available GFDI, UKMI, BAMD and BAMM track guidance models at the 48 and 72
hour time periods.
Some of the models initialized after 0000 UTC 13 September indicated recurvature
toward Baja California or southern California. In fact, an experimental five-day
GFDL model forecast indicated a weakening
tropical cyclone centered just off the
southern California coast at the verifying time of 0000 UTC 18 September. A few
of the official forecasts also indicated recurvature on 13 and 14 September. The best
track shows that recurvature did not occur. State forecast discussions, public
information statements and special weather statements discussing the possible impact
of Linda on southern California were issued by the
Oxnard, California, NWS office.
Some of these products specifically mentioned the uncertainties in forecasting Linda
and asked the media not to overdramatize the storm.
The NHC official intensity forecasts showed a large negative bias (i.e., intensity was
underestimated) while Linda was strengthening and a distinct positive bias (i.e.,
intensity was overestimated) when the cyclone was weakening. These biases are not
uncommon for a tropical cyclone that changes intensity as rapidly as Linda did.
Watches and warnings were neither issued nor necessary for Linda.