Pauline dumped up to 16 inches of rain along the south coast of Mexico and was
responsible for an estimated 230 (or more) deaths in the states of Oaxaca and Guerrero.
a. Synoptic History
Pauline appears to have developed from a
tropical wave that moved from Africa to the
eastern tropical Atlantic Ocean on 16 September. The southern portion of this
wave moved across northern South America and then into the
eastern Pacific Ocean near Panama about ten
days later. By the 3rd of October, a weak lower-tropospheric trough from the northwestern
Caribbean Sea had developed southwestward across southeast Mexico
and northern Central America and disrupted the normally westward
steering currents in this area. By the 3rd, the wave had
developed a distinct area of associated convection and it began
to drift eastward. On the 5th, a well-defined low-level
circulation had formed and tropical depression
status is assigned at a location about 200 nautical miles south of Puerto Angel,
Mexico. The best track begins on the 5th.
Fig. 1 (18K GIF) shows a plot of the
best track of Pauline and this track is listed in Table 1.
With an absence of vertical shear and the
appearance of convective banding features and a
small central dense overcast, the system gradually strengthened to a
tropical storm early on the 6th.
Hurricane status was reached later that day as
satellite imagery showed a hint of an eye feature.
This was soon followed by the appearance of a small well-defined eye which was the
beginning of a period of rapid intensification. A strong high
pressure system over the southeastern United States eroded the
trough over southeastern Mexico and began to influence Pauline's
motion. The hurricane gradually turned toward the northwest on
the 6th through the 8th while intensifying. Pauline reached a
peak intensity of 115 knots on the 7th,
weakened slightly, and again reached 115 knots
on the 8th. By the 8th, the center of the
hurricane was close to the coast of Mexico near Puerto Angel and
interaction of the northern half of the circulation with the high
terrain of Mexico resulted in a weakening trend. The center
crossed the coast at about 0000 UTC on the 9th near Puerto
Escondido with sustained winds estimated at 95 knots.
The center then turned toward the northwest and
accelerated. It moved nearly parallel to the coast for about
24 hours while continuing to weaken. Pauline dissipated by 1200
UTC on the 10th over the state of Jalisco near Tuxpan.
b. Meteorological Statistics
Figures 2 (12K GIF) and
3 (13K GIF) show curves of minimum sea-level pressure
and maximum one-minute surface wind speed, respectively, as a function
of time. Satellite data plotted in these figures are based on the
Dvorak satellite intensity estimating technique as applied at the
Tropical Analysis and Forecast Branch (TAFB),
the Synoptic
Analysis Branch (SAB) and the U.S.
Air Force Global Weather
Center (AFGWC). The ship Rijndam, located about 120 nautical
miles northeast of the center at 0600 UTC on the 7th, reported
sustained winds of 51 knots.
Only limited surface reports have been received from Mexico.
A report of 30 knots with gusts to 60
knots was received from Puerto Escondido at 2145 UTC on
the 8th and there were no reports available after this time.
Acapulco did report continuously while the center was nearby and
the maximum wind from there was 40 knots with
gusts to 51 at 0745 UTC on the 9th. Based on satellite
intensity estimates, sustained winds of 115
knots may have affected the coastline of the state of
Oaxaca near Puerto Angel. But Acapulco's observations indicate
that Pauline was, at most, a minimal hurricane when it reached
the Acapulco area and the primary effect to the state of Guerrero
was the heavy rainfall, which also affected Oaxaca. Table 2
lists the rainfall totals provided by the National Meteorological
Service of Mexico.
c. Casualty and Damage Statistics
Pauline moved along several hundred miles of the Pacific
coastline of Mexico. The associated heavy rainfall sent muddy
flood waters over many communities. The hill-side outskirts of
Acapulco were particularly hard hit by flooding. Media reports
put the death toll at 230 or more persons and hundreds of
thousands were left homeless. Reuters reported that the Red
Cross estimated the death toll at 400, but this has been disputed
by Mexican officials.
Although winds up to 115 knots may
have hit the coast in the Puerto Angel area, there have been no
reports received that specifically describe the wind or
storm surge damage, which may have been
confined to a sparsely populated area.
d. Forecast and Warning Critique
The official track forecast errors for Pauline were close to
the previous ten-year averages for eastern Pacific storms for the
0-, 12-, 24-, 36-, and 48-hour forecast periods. However, at 72
hours, the average official forecast error was 306 nautical miles
and this is 50 percent larger than the ten-year average. This
average is based on only four forecasts and is the result of the
unusual movement toward the east followed by a turn toward the
northwest. The track guidance models had rather large errors at
all forecast periods for this unusual track.
The official intensity forecasts had a rather large negative
bias as the rapid intensification to 115 knots
was not correctly anticipated. The largest official intensity error was
a 55-knot under-forecast issued at 0900 UTC on the 6th.
The operational intermediate advisory issued at 0600 UTC on the 9th
placed the maximum sustained wind speed at 100 knots.
Using the surface data reported from Acapulco, the best track estimate of the wind speed
is 70 knots at 0600 UTC, so the operational
wind speed value was overestimated by 30 knots.
Table 3
lists the various watches and warnings that were issued by the
National Meteorological Service of Mexico.
The initial hurricane warning
was issued at 0900 UTC on the 7th, which is 39 hours prior to the center
reaching the coast and at least 24 hours before hurricane force winds began
at the coast. The initial warning only covered as far northwestward as Punta
Maldonado and was not extended further northwestward to
Zihuatanejo until 0300 UTC on the 9th. This means that there was
only from 3 to 15 hours of warning lead time for the coastal area
from Punta Maldonado to Zihuatanejo. Pauline is estimated to
have dropped below hurricane strength at 0900 UTC on the 9th and
may have done so even earlier, so that the negative effects of a
short lead time for strong winds was minimal. It was the heavy
rains and flash flooding west of Zihuatanejo that was responsible
for the deaths in this area.
Table 3. Watch and warning summary, Hurricane Pauline, October 1997.
Date/Time (UTC) | Action | Location |
07/0900 | hurricane warning issued |
Tapachula to Punta Maldonado |
09/0300 |
hurricane warning extended |
northwestward to Zihuatanejo |
hurricane warning discontinued | Huatulco eastward |
09/0900 |
hurricane warning extended |
northwestward to Manzanillo |
hurricane warning discontinued |
east of Puerto Escondido |
hurricane watch issued |
west of Manzanillo to Puerto Vallarta |
09/1500 |
hurricane warning extended |
northwestward to Puerto Vallarta |
hurricane warning discontinued |
east of Punta Maldonado |
10/0000 | change hurricane warning to
tropical storm warning |
Zihatanejo to Puerto Vallarta |
10/0900 | all warnings discontinued |
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