Hurricane Cesar caused at least 51 deaths and considerable
destruction along its path through the southern Caribbean Sea and
Central America.
a. Synoptic History
The precursor of Hurricane Cesar was a
tropical wave
which passed Dakar, Africa on 17 July and moved westward for a few days
without development. The wave was accompanied by a large 200-mb
anticyclone which suggested a very favorable upper-level
environment for development. Cloudiness and showers began to
increase when the wave was about 900 n mi east of the southern
Windward Islands on 22 July. When the wave neared these islands,
the 24-hour surface pressure changes were of the order of -3.0 mb,
(which is the threshold value that forecasters have typically found
to be associated with a developing system) and a surface
circulation center
began to develop. The incipient center of circulation moved over Trinidad and
Tobago early on 24 July. This system produced rains and gusty winds through a
large portion of the Lesser Antilles. A post-analysis of the surface data and
satellite images indicate that a tropical depression
formed from the disturbed weather at 1800 UTC 24 July when the circulation
center was moving just to the north of the island of Margarita
along the north coast of Venezuela.
The depression moved westward through the southern Caribbean
Sea and reached tropical storm
status at 1200 UTC 25 July in the vicinity of Curacao.
Figure 1a (89K GIF) shows the well defined
upper-level anticyclone (200mb) which accompanied the tropical cyclone at that
time and Fig. 1b (89K GIF)
shows an area of above-normal surface pressure located to the north of the
tropical cyclone
from the Bahamas westward into the Gulf of Mexico. The latter probably reflects
an anomalously strong and persistent high pressure system which
forced Cesar to move westward and even south of due west for
several days. In addition, this dipole in the pressure field is
operationally recognized as a favorable pattern for
disturbances
to develop and strengthen.
Cesar continued its general westward track very close to the
coast of South America and gradually intensified. However, the
development was inhibited by the close proximity to land and it was
not until 1200 UTC 27 July that Cesar reached
hurricane
status over the open waters of the southwestern Caribbean Sea. Cesar
began strengthening more rapidly prior to landfall just north of
Bluefields, Nicaragua, and it reached its maximum intensity of 75
knots and minimum pressure of 985 mb near landfall at 0400 UTC 28
July. Rapid intensification of tropical cyclones near landfall has
been observed in the past; e.g., Hurricanes
Andrew and Cleo
(119K GIF) over south Florida in August 1992 and September 1964.
Cesar crossed Nicaragua and moved into the eastern North Pacific where it
reintensified and became Hurricane Douglas.
The most recent hurricane to hit Nicaragua before Cesar was
Joan (193K GIF), a category 4 hurricane on the
Saffir-Simpson Hurricane Scale,
in October 1988. Joan also redeveloped over the eastern Pacific and
became Tropical Storm Miriam. Cesar's track is shown in
Fig. 2 (58K GIF).
Table 1 is a listing, at six-hour intervals,
of the "best-track"
position, estimated minimum central pressure and maximum 1-minute
surface wind speed.
b. Meteorological Statistics
The best track pressure and wind curves as a function of time are shown in
Figures 3 (21K GIF) and
4 (19K GIF) and are based on
reconnaissance and surface observations,
satellite intensity estimates from the
Tropical Analysis and Forecast Branch (TAFB)
of the Tropical Prediction Center, and denoted as TSAF in the figures.
It also includes estimates from the
Satellite Analysis Branch
(SAB) and the
Air Force Global Weather Central (AFGWC).
Cesar was upgraded to tropical storm status based on a
40-knot 1-minute sustained wind and gusts to 50 knots
observed in Curacao at 1155 UTC 25 July. The central pressure in the best track
associated with Cesar while moving near the coast of Colombia is
estimated to be 1 or 2 mb lower that reported by the reconnaissance
plane at that time because the storm's close proximity to land prevented
the plane from reaching the pressure center. Ship observations and the
Hurricane Research Division (HRD)
surface wind analysis indicate that 34-knot winds extended northward from the
center for about 240 n mi. San Andres experienced calm winds at
2128 UTC followed by 64-knot gusts marking the passage of a portion
of Cesar's center. The strengthening just prior to landfall is
supported observations from the reconnaissance plane just before it
departed the storm center. Data indicate the formation of an
eye at 0050 UTC 28 July,
a closed eyewall
of 15 n mi diameter at 0256 UTC and a drop in the surface pressure of 3 mb in
1 hour. Satellite images confirmed the strengthening at landfall by showing
an embedded center within cold tops between -54 to -63C
corresponding to a T-number of 4.5 on the Dvorak scale.
Tables 2 and 3
contain selected surface observations and ships reporting 34-knot winds or higher.
c. Casualty and Damage Statistics
Cesar was responsible for at least 51 deaths on its trek
through the Caribbean Sea and Central America. Most of the deaths
were attribute to heavy rainfall which caused flash flooding and
mudslides. The death total includes 26 people in Costa Rica which
was not in the direct path of the hurricane but was hit by floods
and mud slides.
d. Forecast and Warning Critique
Table 4 summarizes the watches and warnings
associated with Cesar. Hurricane warnings
for Nicaragua were issued about 30 hours before landfall. In general, the
official forecast always kept the tropical cyclone on a general westward track with
about the correct amount of intensification. The official forecast errors increased
from 56 n mi at 12 hours to 150 n mi at 72 hours. The 10-year
average errors are 50 and 296 n mi respectively. The GFDI (an interpolated version of the
GFDL model) performed much better than
the official forecast at all periods and the errors ranged from 36
n mi at 12 hour to 90 n mi at 72 hours. Most of the other
dynamical models including UKMI, LBAR, BAMM and BAMS produced
errors larger that 300 n mi at 72 hours.
Table 4. Watch and warning summary, Hurricane Cesar, July 1996.
Date/time
(UTC) | Action | Location |
| 25/1200 | tropical storm warning issued |
Curacao; Aruba; Vela del Coro, Venezuela to Barranquilla, Colombia |
| 25/2100 | tropical storm warning discontinued |
Curacao |
| 26/0000 | tropical storm warning discontinued |
Aruba. Coast of Venezuela to Barranquilla, Colombia. |
| 26/0900 | hurricane watch issued |
San Andres;, Providencia. Bluefields Nicaragua to Limon, Honduras. |
| 26/2100 | hurricane warning isued |
San Andres; Providencia; Bluefields to Limon. |
| 28/0900 | hurricane warning discontinued |
San Andres; Providencia; Bluefields to Limon. |
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