TROPICAL CYCLONE REPORTS
Tropical Storm Barbara
Tropical Storm Cosme
Tropical Storm Erick
Tropical Depression Six-E
Tropical Storm Henriette
Tropical Storm Ivo
Tropical Storm Lorena
Tropical Depression Fourteen-E
Tropical Storm Manuel
Tropical Cyclone Report
21 September - 3 October 2001
Hurricane Juliette was a category 4 hurricane (on the
Saffir-Simpson Hurricane Scale) that brought 80-knot winds and
heavy rain to the southern Baja California peninsula of Mexico. It
also caused flooding in the state of Sonora on mainland Mexico and
caused two deaths.
a. Synoptic History
The tropical wave that produced Tropical Depression Nine on 19
September over the western Caribbean was also the origin of
Juliette. Tropical Depression Nine dissipated over Central America
on the 20th. But its remnants and associated tropical
wave continued westward over the eastern Pacific Ocean and became a
depression at 0600 UTC on the 21st, about 90 nautical
miles south of the coast of Guatemala. The "best track" begins at
this time. Figure 1 shows a map of the best track and
Table 1 lists
the best track positions, wind speeds and central pressures every
six hours. Curves of wind speed and pressure versus time are shown
in Figure 2 and Figure 3,
along with the data on which these curves are
Juliette's track was generally west-northwestward from the
21st to the 26th, while located south of a
mid-level ridge. This track was approximately parallel to the coast
of mainland Mexico, and the center remained from 100 to 200
nautical miles offshore. Under a weak vertical shear environment,
Juliette strengthened. It became a hurricane on the
23rd, rapidly intensified to 115 knots with a pinhole
eye on the 24th and reached 125 knots on the
25th. Aircraft and TRMM satellite data indicate that
there were several concentric eyewalls and eyewall replacement
cycles during the 24th through 27th.
By the 26th, a strong trough west of the U.S. west
coast began digging southeastward and Juliette gradually turned
toward the north and began weakening. Moving very slowly northward,
the center passed just west of Cabo San Lucas on the southern tip
of Baja California on the 28th as wind speeds decreased
to near 80 knots. These winds, heavy rain, and waves pounded the
southern peninsula. Under increasing vertical shear and
progressively cooler sea surface temperatures, Juliette moved
inland on the 30th near San Carlos on the west coast of
Baja California, as a weakening 35-knot storm. It then moved over
the waters of the central Gulf of California as a depression and
finally dissipated on the 3rd of October over the far
northern Gulf of California.
Satellite imagery showed that clouds associated with the
remnants of Juliette spread into New Mexico, Arizona, and southern
b. Meteorological Statistics
Observations plotted in Figure 2 and Figure 3
Dvorak technique intensity estimates from the Tropical Analysis and
Forecast Branch (TAFB), the Satellite Analysis Branch (SAB) and the
U.S. Air Force Weather Agency (AFWA), as well as flight-level and
dropwindsonde observations from three flights of the
53rd Weather Reconnaissance Squadron of the U. S. Air
Force Reserve Command and from one flight of a NOAA research
In Figure 2,
it is seen that satellite objective T-number wind
speed estimates were considerably higher than the reconnaissance
aircraft wind speeds. On the 25th, the highest aircraft
flight-level winds reduced to a surface wind speed of 118 knots,
while, at the same time, objective T-number wind speeds were 140
knots. The 125-knot best track value is a compromise between these
values giving more weight to the aircraft data. This same
adjustment was applied to objective T-numbers on the
25th, when there was no reconnaissance.
Whereas a number of hurricanes have had lower pressures
estimated from satellite imagery, the aircraft-measured 923
millibars on the 25th (Figure 3) is the second-lowest
measured sea-level pressure on record in the northeastern Pacific
Ocean. Only Hurricane Ava in June 1973 had a lower measured
pressure of 915 millibars.
The highest wind observation from Baja California was 76 knots
sustained with a gust to 94 knots at about 0000 UTC on the
30th, from an automatic weather station at Cabo San
Lucas. Rainfall totals include 5.35 inches on the 27th
at Santiago on the extreme southern peninsula, 6.59 inches on the
30th at Empalme in the Sonora Province on the mainland,
and 8.16 inches on October 3rd at San Felipe in the
extreme northern peninsula. An unconfirmed report was received of
"over a foot of rain" at Cabo San Lucas.
Ships reports of wind speeds greater than 33 knots are listed in
The circulation became poorly defined as it moved over land on
the west coast of Baja California near San Carlos on the
30th. The best track estimate of 35 knots at landfall is
rather uncertain as the wind speeds were decreasing fast.
shows a continuous depression stage track across Baja California
and the northern Gulf of California on the 30th. It is
possible that the circulation dissipated over or near the southern
Peninsula early on the 30th and another center formed in
the northern Gulf of California later that day.
c. Casualty and Damage Statistics
Two deaths are attributed to Juliette. The Associated Press
stated that a U.S. tourist surfing near the Baja California coast
drowned in high seas on September 27th.
The Mexican government news
agency Notimex reported that a fisherman died near Acapulco when
his small open boat capsized in high seas on the
The Notimex news agency also reported that Juliette "clobbered"
the tourist resort of Cabo San Lucas, isolating it from the outside
world for several days. The hurricane also caused flooding on
mainland Mexico, driving more than 38,000 people from their homes
in coastal areas of Sonora state.
Thunderstorm activity associated with the cyclone's remnants
moved into southern California on the 30th, knocking
down trees and power lines across the Coachella Valley.
d. Forecast and Warning Critique
Average official track errors (with the number of cases in
parentheses) were 33 (35), 53 (31),74 (29), 103 (27), and 145 (23)
n mi for the 12, 24, 36, 48, and 72 h forecasts, respectively.
These errors are lower than the average official errors for the
previous 10-years (37, 68, 99, 128, and 185 n mi, respectively).
Several of the track guidance models had errors even smaller than
the official errors, including the AVN, UKMET, and NOGAPS
Average official intensity errors were 11, 15, 15, 15, and 19 kt
for the 12, 24, 36, 48, and 72 h forecasts, respectively. For
comparison, the average official intensity errors over the 10-yr
period 1991-2000 are 7, 12, 16, 19, and 21 kt, respectively. The
best intensity guidance model, SHIPS, had errors of 14, 15, 14, 14,
and 16 knots, respectively.
Table 3 lists the watches and warnings that were issued for
Table 1: Best track for Hurricane Juliette, 21 September - 3 October 2001.
|Lat. (°N)||Lon. (°W)
|21 / 0600||12.6||91.1||1007||30||tropical depression
|21 / 1200||13.0||92.8||1005||35||tropical storm
|21 / 1800||13.5||94.3||997||35||"
|22 / 0000||13.6||95.8||996||40||"
|22 / 0600||13.6||97.3||996||45||"
|22 / 1200||13.5||98.5||995||45||"
|22 / 1800||13.5||99.7||994||45||"
|23 / 0000||14.2||100.4||992||50||"
|23 / 0600||14.6||101.3||986||55||"
|23 / 1200||14.8||102.2||976||65||hurricane
|23 / 1800||14.9||102.8||960||85||"
|24 / 0000||14.8||103.3||941||110||"
|24 / 0600||15.0||103.5||941||115||"
|24 / 1200||15.1||103.8||952||100||"
|24 / 1800||15.2||104.1||957||95||"
|25 / 0000||15.4||104.7||941||115||"
|25 / 0600||15.9||105.3||935||125||"
|25 / 1200||16.2||106.2||928||125||"
|25 / 1800||16.4||107.2||923||125||"
|26 / 0000||16.8||107.9||925||125||"
|26 / 0600||17.5||108.6||930||115||"
|26 / 1200||18.2||109.1||935||105||"
|26 / 1800||18.8||109.8||940||100||"
|27 / 0000||19.4||110.3||942||95||"
|27 / 0600||20.1||110.5||949||90||"
|27 / 1200||20.7||110.8||955||85||"
|27 / 1800||21.4||110.7||961||80||"
|28 / 0000||22.3||110.7||968||80||"
|28 / 0600||22.8||111.0||971||75||hurricane
|28 / 1200||23.0||111.1||981||70||"
|28 / 1800||23.2||111.1||987||60||tropical storm
|29 / 0000||23.4||111.2||987||60||"
|29 / 0600||23.6||111.3||983||65||hurricane
|29 / 1200||23.8||111.5||985||65||"
|29 / 1800||24.0||111.7||990||45||tropical storm
|30 / 0000||25.0||112.0||1000||35||"
|30 / 0600||26.1||111.8||1003||30||tropical depression
|30 / 1200||27.1||111.8||1005||30||"
|30 / 1800||28.2||112.0||1005||30||"
|01 / 0000||28.7||112.2||1005||25||"
|01 / 0600||29.2||112.5||1006||25||"
|01 / 1200||29.7||112.7||1006||25||"
|01 / 1800||30.2||113.1||1006||30||"
|02 / 0000||30.4||113.3||1006||30||"
|02 / 0600||30.6||113.6||1006||30||"
|02 / 1200||30.5||113.8||1006||30||"
|02 / 1800||30.4||114.4||1007||30||"
|03 / 0000||30.2||114.6||1008||25||"
|03 / 0600||dissipated
|30 / 0000||25.0||112.0||1000||35||landfall near San Carlos, Mexico on Baja
|25 / 1800||16.4||107.2||923||125||minimum pressure
Table 2: Selected ship observations of tropical storm or greater
winds associated with Hurricane Juliette, 21 September - 3 October 2001.
|Ship Name or Call Sign||Date/Time (UTC)||Lat. (°N)||Lon. (°W)||Wind dir/speed (deg/kt)||Pressure (mb)
Table 3: Watch and warning summary, Hurricane Juliette, 21 September - 3 October 2001.
|21/1800||tropical storm warning||Salina Cruz to Acapulco
|21/2100||tropical storm watch||west of Acapulco to Lazaro
|22/0300||tropical storm warning discontinued||Salina Cruz to Puerto Angel
|22/0300||tropical storm warning||Acapulco to Zihuatanejo
|22/0300||tropical storm watch||Zihuatanejoto Manzanillo
|22/1500||all watches and warning
|23/1500||hurricane watch||Lazaro Cardenas to Manzanillo
|23/2100||hurricane watch||Manzanillo to Cabo Corrientes
|23/2100||tropical storm warning||Lazaro Cardenas to Cabo
|25/1500||all watches and warning
|26/0300||tropical storm warning||Lazaro Cardenas to Cabo Corrientes
|26/0300||tropical storm watch||southern Baja peninsula - south of a line from Cabo San Lazaro to Los Burros
|26/1500||tropical storm warning||southern Baja peninsula - south of a line from Cabo San Lazaro to Los Burros
|26/1500||tropical storm warning discontinued||Lazaro Cardenas to Cabo Corrientes
|27/0300||tropical storm warning extended north||Cabo San Lazaro to Punta Abreojos and Los Burros to Loreto
|27/0900||hurricane warning||west coast of Baja - south of 24 deg. N
east coast of Baja - south of Punta Arena
|27/2100||hurricane warning extended||24 deg. N to Cabo San Lazaro and Punta Arena to Los Burros
|28/0300||tropical storm warning extended||east coast of Baja - Loreto to Santa Rosalia
|28/0300||tropical storm warning||Mazatlan to Yavaros
|28/2100||tropical storm warning discontinued||Mazatlan to Yavaros
|28/2100||replace hurricane warning with tropical storm warnings||west coast of Baja - south of San Lazaro
east coast of Baja - south of Los Burros
|29/0300||hurricane warnings||southern Baja peninsula south of 25 deg. N
|29/1500||replace hurricane warning with tropical storm warning...tropical storm
warning now in effect for||southern Baja peninsula south of Punta Abreojos on the west coast and south of
Santa Rosalia on the east coast
|30/0300||tropical storm warning discontinued||south of 24 deg. N along both coasts
Best track positions for Hurricane Juliette, 21
September- 03 October 2001.
Best track maximum sustained surface wind speed curve
for Hurricane Juliette, 21 September-03 October 2001, and the
observations on which the best track curve is based. Aircraft
observations have been adjusted for elevation using 90%, 80%, and
80% reduction factors for observations from 700 mb, 850 mb, and
1500 ft, respectively. Dropwindsonde observations include actual 10
m winds (sfc), as well as surface estimates derived from the mean
wind over the lowest 150 m of the wind sounding (LLM), and from the
sounding boundary layer mean (MBL).
Best track minimum central pressure curve for
Hurricane Juliette, 21 September-03 October 2001, and the
observations on which the best track curve is based.