Lili was the sixth category 3 Atlantic
hurricane on the
Saffir/Simpson hurricane scale during 1996.
It moved across central Cuba and the central Bahamas with sustained winds in the
80 to 90 knot range.
a. Synoptic History
A tropical wave
moved from Africa to the Atlantic Ocean on 4
October accompanied by a large cyclonic rotation of low clouds
and a mid-tropospheric jet. The wave moved westward under an
unfavorable strong vertical shear environment and, on 11 October,
passed through the Windward Islands where a marked wind shift and
large 24-hour pressure changes were observed. It reached the
southwestern Caribbean on the 13th, where a pre-existing area of
low surface pressure was located.
The system developed a well-defined low-level circulation and
became a tropical depression at about 1200 UTC on the 14th, just
east of Nicaragua, and began moving northwestward at about eight
knots. The track in Fig. 1
and Table 1 begins at this time.
Over the next two days, the depression turned north and then
north-northeastward in response to a weak mid- to upper-level low
over the Gulf of Mexico. Although there appeared to be considerable convective
banding and falling surface pressures, aircraft data showed that the depression did not strengthen
to a storm until early on the 16th, when the
center was close to Swan Island.
With a well-established outflow over the circulation, Lili strengthened to a
hurricane on the 17th.
Moving slowly, the center executed a small cyclonic loop just
north of Swan Island on the 16th and wobbled again on the 17th as
it approached the Isle of Youth, Cuba. The center passed over
the eastern side of the Isle of Youth near 0100 UTC on the 18th
and made landfall on the south coast of mainland Cuba in Matanzas
Province at 0930 UTC. The maximum sustained surface winds had
strengthened to near 85 knots at landfall as Lili turned eastward
for a twelve-hour crossing of central Cuba on the 18th.
A major trough in the westerlies moved to the eastern United
States as Lili approached Cuba and this resulted in the hurricane
accelerating mostly northeastward to a forward speed of near 25
knots by late on the 19th.
The hurricane maintained its strength over Cuba. The pressure
was measured by aircraft at 975 millibars just before landfall
and the same pressure was measured again when the eye moved back
over water. Accelerating toward the Bahamas, there was further
strengthening and Lili went through the central Bahamas early on
the 19th with sustained winds of near 90 knots. The
eye, 30 to 40 nautical miles wide,
moved over Great Exuma and San Salvador and the eye wall affected
portions of Long Island, Rum Cay, and Cat Island.
Shortly thereafter, at 0000 UTC on the 20th and just east of the
Bahamas, the hurricane reached its peak strength, with an
estimated 100-knot maximum sustained wind and a central surface
pressure of 960 mb. This is a category 3 on the
Saffir/Simpson hurricane intensity scale
and Lili is the sixth category 3 or
higher hurricane in the Atlantic basin in 1996.
Lili continued moving northeastward, its center passing about 130
n mi southeast of Bermuda on the 20th. By now, the strongest
winds were on the southeast side of the center and Bermuda's
sustained winds did not reach tropical storm force. Lili's winds
gradually decreased from the 100-knot maximum on the 20th to
65 knots on the 21st.
On the 22nd, having turned eastward, the forward motion
decelerated to almost stationary as a mid-level short-wave high
pressure ridge came into longitudinal phase with Lili. Lili
drifted erratically eastward across the central north Atlantic
until the 24th, when another acceleration toward the northeast
began. Lili reintensified to 85 knots on the 25th and finally
weakened to a tropical storm on the 26th, as the center was
passing about 300 n mi northwest of the Azores. Lili is estimated to have become
extratropical on the 27th. It remained
a 55-knot extratropical storm until crossing Great Britain on the
28th. Its remnants crossed the northern European mainland on the
29th.
b. Meteorological Statistics
Figures 2 and 3
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 is based on the
Dvorak satellite intensity estimating technique
as applied at the Tropical Analysis and Forecast Branch (TAFB),
the Satellite Analysis Branch
(SAB) and the U.S. Air Force Global Weather Center
(AFGWC).
Aircraft data is from eleven aircraft reconnaissance missions
into Lili over a five-day period, from the 15th to the 20th,
resulting in 37 center penetrations. Seven of the missions were
performed by the
U.S. Air Force Reserve Unit
out of Keesler AFB, Mississippi. The other four missions were performed by the
NOAA research aircraft
when Lili's center was near Cuba. The maximum
wind speed measured by aircraft was 112 knots at the 700 mb
level, at 0855 UTC on the 19th in the southeast quadrant. The
minimum surface pressure from the aircraft was 960 millibar at
1218 UTC on the 19th.
Table 2 lists a selection of significant surface
observations. The highest sustained wind from Cuba was a 10-minute average of
80 knots reported from Cayo Largo del Sur, an island located
about 50 nautical miles east of the Isle of Youth. The center
was over mainland Cuba and about 40 nautical miles north of the
island at the time of the report. An 80-knot 10-minute wind was
also reported from San Salvador in the central Bahamas at the
time that the center was located about 15 nautical miles to its
north-northwest.
Table 3 lists selected ship reports of winds greater
than 33 knots that were caused by Lili. Two hours after the report from
San Salvador, at 1200 UTC on the19th, a ship with call sign
ZCBC3 reported an estimated wind speed of 99 knots, while located
about 20 nautical miles south of the center. The 112-knot
aircraft wind was measured only a few hours earlier and the hurricane's estimated
maximum sustained wind speed of 100 knots
is based on these measurements.
There was heavy rainfall over portions of Cuba with over 26 inches accumulated at La Moza.
Sustained wind speeds to about 45 knots with gusts to as high as
78 knots (from Alderney, a Channel island) were reported from
Great Britain, when Lili was extratropical, on the 28th and 29th.
c. Casualty and Damage Statistics
During the formative state of the tropical cyclone,
heavy rain occured over portions of Central America. The Associated Press
reported five drowning deaths in Honduras and three deaths in
Costa Rico. In addition, thousands were left homeless in both of
these countries and there was flooding in Nicaragua as well.
In Cuba, there was extensive damage to agriculture and thousands
were made homeless according to Reuters news. Reuters also
reported that six were killed in Great Britain from Lili as an
extratropical storm. Four died in traffic accidents and two
fishermen were swept into the sea.
In the Bahamas, reports from Georgetown on Great Exuma island
suggest that many houses were substantially damaged and many
boats were sunk. A storm tide
of 15 feet above mean sea level was estimated on the north side of Great Exuma.
d. Forecast and Warning Critique
Table 4 lists the various watches and warnings along with
their issuance times. Hurricane warnings
were issued for the Isle of Youth, Cuba, almost 24 hours before hurricane conditions began.
The lead time for the mainland Cuba landfall was 30 hours. The
hurricane warning lead time for the central Bahamas was somewhat
less...15 to 18 hours. The hurricane watch
was issued for Cuba 52 hours before the center reached the Isle of Youth and Lili was
only a tropical depression at the time of issuance.
The average official track forecast errors for Lili, in nautical
miles, ranged from 57 at 12 hours, 88 at 24 hours, 119 at 36
hours, 142 at 48 hours, to 200 at 72 hours. The 12-hour official
errors are larger than the previous 10-year average and the rest
are smaller, considerably so at 48 and 72 hours, than the
previous 10-year averages.
Once again, a good track forecast performance is attributed to
excellent numerical model guidance. For example, the looping
motion on the 16th followed by another wobble on the 17th were
both forecast by the 0000 UTC GFDL
model run on the 16th. Another point of interest is at 1200 UTC on the 18th, when the
center had just made landfall in Cuba and was accelerating in the
general direction of southeast Florida and perhaps less than 24
hours away. No warnings were issued for the Miami and Fort
Lauderdale metropolitan areas and this was possible because of
the confidence in the guidance models which showed the hurricane
turning northeastward and missing south Florida.
Tropical storm warnings
were issued for the Florida Keys however and Table 2
shows that sustained winds did not quite reach tropical storm
force there.
The GFDL model absolute wind speed forecast errors at 72 hours
averaged 11 knots for 16 cases during Lili. This is considerably
smaller that the 1995 average GFDL error at 72 hours of 20 knots
and is also smaller than the average official error of 22 knots
for the same 16 Lili cases.
Table 4. Watch and warning summary, Hurricane Lili, October 1996.
Date/time (UTC) | Action | Location |
15/2100 | hurricane watch |
Cuba: provinces of Pinar del Rio and Havana and Isle of Youth |
16/0300 | tropical storm warning |
Mexico: Yucatan Peninsula from Isla Mujeres to Bahia de Chetumal |
16/0600 | tropical storm warning |
Mexico: Yucatan Peninsula from cabo Catoche to Bahia de Chetumal |
16/1200 | tropical storm warning |
Cayman Islands |
16/1500 |
hurricane watch and
tropical storm warning |
Cuba: provinces of Pinar del Rio, Havana, Matanzas, Villa Clara, and Cienfuegos and Isle of
Youth |
17/0300 |
hurricane warning |
Cuba: provinces of Pinar del Rio, Havana, Matanzas, Villa Clara, and Cienfuegos and Isle of
Youth |
17/0900 |
tropical storm warning discontinued |
Mexico: Yucatan Peninsula from cabo Catoche to Bahia de Chetumal |
17/1045 | hurricane watch and
tropical storm warning |
Cayman Islands |
17/1500 | hurricane warning |
Cuba: provinces of Camaguey, Ciego de Avila, and Sancti Spiritus |
17/2100 | tropical storm warning |
Florida Keys from Key Largo to Dry Tortugas including Florida Bay |
hurricane watch | Northwest Bahamas |
watch and warning discontinued | Cayman Islands |
18/0900 | hurricane warning |
northwest Bahamas |
hurricane watch | central Bahamas |
18/1500 | hurricane warning |
central Bahamas |
hurricane warning discontinued |
Cuba: Isle of Youth |
18/1800 |
hurricane warning discontinued |
Cuba: from Havana westward |
tropical storm warning discontinued |
Florida Keys and Florida Bay |
19/0300 | hurricane warning discontinued |
northwest Bahama Islands of Grand Bahama, Abaco, and Bimini |
19/0500 | tropical storm warning |
southeast Bahamas and Turks and Caicos Islands |
19/0600 | hurricane warning discontinued |
All of Cuba |
19/1200 | hurricane warning discontinued |
northwest Bahamas |
19/1800 | all warnings discontinued |
all of Bahamas |