Keith was a rapidly-intensifying tropical cyclone over the northwestern
Caribbean Sea, reaching Category 4 on the Saffir-Simpson Hurricane Scale as
it stalled just off the coast of Belize. Keith affected the coastal islands
of Belize as a Category 3 hurricane, but weakened to a tropical storm before
actually making landfall in mainland Belize. After weakening to a tropical
depression while crossing the Yucatan Peninsula, Keith re-intensified over
the southwestern Gulf of Mexico and made landfall in northeastern Mexico as
a Category 1 hurricane.
a. Synoptic history
A tropical wave moved off the west coast of Africa on 16 September. The
wave showed signs of organization over the Atlantic from 19-22 September,
but strong vertical shear prevented development then. The wave continued
westward into the Caribbean Sea and started to become better organized on 27
September, when the first Dvorak satellite intensity estimate was made.
Development continued, and an Air Force Reserve Hurricane Hunter aircraft
found that the system became a tropical depression about 60 n mi
north-northeast of Cape Gracias a Dios, Nicaragua, around 1800 UTC 28
September (Table 1 and Figure 1).
The depression moved northwestward, and a second flight around 1800 UTC
29 September indicated that the cyclone had become Tropical Storm Keith.
Rapid intensification began near that time, and Keith's central pressure
fell from 1000 mb at 1814 UTC on the 29th to 939 mb at 0708 UTC
1 October -- a 61 mb fall in about 37 h. A 38 mb fall occurred from 1808 UTC
on the 30th to the time of minimum pressure, which qualifies as
explosive deepening as defined by Dunnavan (1981). Maximum winds reached
120 kt -- Category 4 on the Saffir-Simpson hurricane scale near the time of
minimum pressure. During this rapid development, Keith slowed and turned
westward, with the eye moving to a position just southeast of the coastal
islands of Belize. A slight weakening occurred later on the 1st,
and Keith was a Category 3 hurricane when the eyewall moved over Ambergris
Cay and Caye Caulker, Belize near 1800 UTC.
Motion then became slow and erratic, with the eye of Keith meandering just
off the Belize coast into 3 October. This was partly due to high pressure
over the Gulf of Mexico blocking the hurricane's path, and partly due to
formation of a tropical disturbance (later to become Tropical Storm Leslie)
near western Cuba. The cyclone weakened dramatically during this time.
Keith was a Category 1 hurricane when the center crossed Ambergris Cay,
Belize near 2300 UTC on the 2nd and a 60-kt tropical storm when
the center crossed the Belize mainland coast between Belize City and
Chetumal, Mexico around 0300 UTC on the 3rd.
Once inland, Keith began moving west-northwestward, and this direction of
general motion continued with a gradual acceleration until its final
landfall. It weakened to a depression over the Yucatan Peninsula, then
re-intensified to a tropical storm over the Bay of Campeche on 4 October.
Keith regained hurricane status on 5 October, and maximum winds increased to
80 kt as the hurricane made landfall about 20 n mi north of Tampico Mexico
around 1800 UTC that day. Keith again weakened over land, and the cyclone
dissipated over northeastern Mexico the next day.
b. Meteorological statistics
Table 1
shows the best track positions and intensities for Keith, with the
track plotted in Figure 1. Figure 2
and Figure 3 depict the curves of minimum
central sea-level pressure and maximum sustained one-minute average
"surface" (10 m above ground level) winds, respectively, as a function of
time. These figures also contain the data on which the curves are based:
aircraft reconnaissance and dropsonde data from the Air Force Reserve
Hurricane Hunters, and satellite-based Dvorak technique intensity estimates
from the Tropical Analysis and Forecast Branch (TAFB), the Satellite
Analysis Branch (SAB) of the National Environmental Satellite Data and
Information Service (NESDIS), and the Air Force Weather Agency (AFWA).
The Hurricane Hunters flew 11 missions into Keith with a total of 34 center
fixes. The maximum flight-level wind reported during the storm was 133 kt
at 850 mb at 2220 UTC 1 October, while the maximum wind reported from
dropsondes in the eyewall was 153 kt at 883 mb at 0705 UTC 1 October. The
maximum surface wind estimated from the dropsondes was 115 kt at 0600 UTC 1
October. The best track minimum pressure was 939 mb, which requires further
comment. Observed dropsonde pressures at peak intensity were 943 and 942 mb.
However, the reported surface winds from those sondes were in excess of 40
kt, indicating they did not splash in the center of the eye. The 939 mb
pressure is based on extrapolation of pressure values from the 700 mb flight
level using the temperature and moisture data from the sondes.
The core of Keith missed most observing stations near the track. The
maximum reported wind from any official station was 40 kt sustained with
gusts to 55 kt at Tampico, Mexico at 1445 UTC 5 October. The few other
significant land observations are summarized in
Table 2. Amateur radio
operators reported measured winds of 90-110 kt in San Pedro (on Ambergris
Cay) and Caye Caulker, Belize on 1 October while under the eyewall. While
these observations are significant, their reliability is uncertain and they
are not included in Table 2.
Also not included is a 35 kt report from a Mexican oil platform in the Bay
of Campeche at 1700 UTC 4 October, as the height of the anemometer is
unknown.
The only ship to report tropical storm-force winds in Keith was the
Edyth L (call sign C6YC), which reported 60 kt winds and a
1009.0 mb pressure in the northwestern Caribbean Sea at 1800 UTC
30 September.
The only known storm surge observation was from Caye Caulker, where a 4-5 ft
surge from the west occurred. Tides of 4 ft below normal were
noted on the Belize mainland coast while Keith was just offshore of the
coastal islands. The National Hurricane Center also received reports that
northerly winds associated with Keith had temporarily blown the water out of
the Bay of Chetumal and people were walking on the exposed bay bottom. This
was a potentially dangerous situation, as the water could have quickly
returned had Keith moved and the winds shifted.
Keith's slow motion led to torrential rainfall over portions of Central
America, especially Belize. The largest storm total was 32.67 in at the
Philip Goodson International Airport in Belize City. Several other totals
exceed 10 in. Table 2a
summarizes the available rainfall data.
c. Casualty and damage statistics
Reports from the Meteorological Service of Belize and the media indicate the
death toll from Keith is 24: 5 in Belize, 12 in Nicaragua, 6 in Honduras,
and 1 in Mexico. The deaths in Belize occurred when two catamarans broke
loose during the storm. Five of the deaths in Honduras occurred when an
aircraft disappeared near Roatan Island during the storm. The other deaths
are apparently due to flooding from heavy rains. The estimated damage to
property, agriculture, and tourism in Belize is $225 million. Much of the
property damage occurred on Ambergris Cay and Caye Caulker.
There are no reports of damage or casualties from Keith's final landfall in
northeastern Mexico. Heavy rains in Guatemala caused flooding in ten towns,
but no estimates of the damage are available.
d. Forecast and warning critique
Table 3
shows the average track forecast errors during Keith, including the
official forecast error, the 10-year average forecast error, and the track
guidance errors. The official forecast errors were better than the 10-year
average at 12 and 24 h and significantly worse than the 10-year average at
longer times. The official forecasts were worse than the CLImatology and
PERsistence (CLIPER or CLIP in the table) forecasts and thus had no skill.
Many of the numerical guidance models also outperformed the official
forecast, with the most notable being the U.S. Navy version of the GFDL
model (GFDN), which had errors of 25, 33, 68, 97, and 136 n mi at 12, 24,
36, 48, and 72 h respectively. This model likely performed well due to both
it and its parent NOGAPS model (NGPS in the table) doing a better (although
not perfect) job of catching Keith's westward motion. The AVN model and its
associated guidance (including the GFDL) showed a consistent bias of being
too far to the north partly due to mislocation of the vortex in the model.
NHC track forecasts of Keith also showed a consistent bias to the north,
likely in response to the AVN, GFDL, and UKMET guidance.
Figure 4 shows an
example of the available guidance at 1200 UTC 2 October. Note that all the
guidance forecasts a northward to northwestward motion even when initialized
with a stationary storm, and that the official forecast followed the right
side of the guidance. Also note that in this example the actual track was
outside the envelope of the guidance. NHC's 72 h track forecast errors were
never less than 225 n mi, and most were in the 325-390 n mi range. It
should be noted that once Keith moved into the Gulf of Mexico the forecast
accuracy improved considerably: a 36 h forecast issued 30 h before the final
landfall had an error of 66 n mi and a 24 h forecast verifying at landfall
had only a 70 n mi error, both better than the
respective 10-year averages.
The official intensity forecast errors for Keith were 13, 22, 23, 18, and 23
kt for 12, 24, 36, 48, and 72 h. This is significantly worse than the
10-year average of 7, 11, 13, 16, and 19 kt at those times. The largest
intensity forecast error was a 60 kt underforecast of the 36 h intensity
from the 1800 UTC 29 September forecast. The poor forecasts had four
causes: 1) Underestimating how quickly Keith would strengthen over the open
Caribbean, 2) Incorrect track forecasts that led to forecasting a weakening
Keith over the Yucatan Peninsula when the storm actually stayed over water,
3) An underestimation of how quickly Keith would weaken after it neared the
coast of Belize, and 4) An underestimation of how much Keith would
re-intensify over the Gulf of Mexico.
The poor track forecasts had an impact on watches and warnings. Watches and
Warnings were posted for the Mexican portion of the Yucatan Peninsula late on
the 29th and early on the 30th. However, most of these
areas were not seriously affected by Keith. Hurricane warnings for the
actual landfall area in Belize were issued about 24 h before the eyewall of
Keith arrived over the coastal islands.
Table 4
lists the watches and warnings associated with Keith.
Acknowledgements
Carlos Fuller of the Meteorological Service of Belize provided many of the
observations used in this report. James Franklin created several of the
figures.
References
Dunnavan, G. M., 1981: Forecasting intense tropical cyclones using 700-mb
equivalent potential temperature and sea-level pressure. NOCC/JTWC
Technical Note 81-1, 12 pp.
Table 1.
Best track, Hurricane Keith, 28 September - 6 October 2000.
Date/Time (UTC) | Position |
Pressure (mb) |
Wind Speed (kt) | Stage |
Lat. (°N) | Lon. (°W) |
28/1800 | 16.1 | 82.9 | 1005 | 25 | tropical depression |
29/0000 | 16.2 | 83.3 | 1004 | 25 | " |
29/0600 | 16.6 | 83.6 | 1003 | 30 | " |
29/1200 | 16.9 | 84.0 | 1002 | 30 | " |
29/1800 | 17.4 | 84.8 | 1000 | 40 | tropical storm |
30/0000 | 17.7 | 85.4 | 993 | 45 | " |
30/0600 | 17.9 | 86.0 | 987 | 55 | " |
30/1200 | 17.9 | 86.4 | 982 | 65 | hurricane |
30/1800 | 17.9 | 86.7 | 977 | 75 | " |
01/0000 | 17.9 | 86.9 | 955 | 100 | " |
01/0600 | 17.9 | 87.2 | 941 | 120 | " |
01/1200 | 17.9 | 87.4 | 944 | 115 | " |
01/1800 | 17.9 | 87.7 | 950 | 110 | " |
02/0000 | 17.8 | 87.9 | 959 | 100 | " |
02/0600 | 17.6 | 87.8 | 974 | 80 | " |
02/1200 | 17.7 | 87.8 | 980 | 70 | " |
02/1800 | 17.7 | 87.9 | 987 | 65 | " |
03/0000 | 17.9 | 88.0 | 989 | 60 | tropical storm |
03/0600 | 18.0 | 88.4 | 990 | 45 | " |
03/1200 | 18.3 | 88.8 | 995 | 30 | tropical depression |
03/1800 | 18.6 | 89.5 | 998 | 30 | " |
04/0000 | 19.0 | 90.4 | 1000 | 25 | " |
04/0600 | 19.5 | 91.4 | 1000 | 30 | " |
04/1200 | 19.9 | 92.5 | 999 | 35 | tropical storm |
04/1800 | 20.3 | 93.5 | 996 | 40 | " |
05/0000 | 20.7 | 94.8 | 988 | 60 | " |
05/0600 | 21.2 | 96.1 | 987 | 65 | hurricane |
05/1200 | 21.8 | 97.0 | 983 | 75 | " |
05/1800 | 22.6 | 97.9 | 980 | 80 | " |
06/0000 | 23.2 | 99.0 | 988 | 45 | tropical storm |
06/0600 | 23.5 | 100.0 | 1002 | 30 | tropical depression |
06/1200 | 23.8 | 101.0 | 1007 | 20 | " |
06/1800 | | dissipated |
|
01/0700 | 17.9 | 87.3 | 939 | 120 | minimum pressure |
| Landfalls |
02/2300 | 17.9 | 88.0 | 988 | 65 | landfall at Ambergris Cay, Belize |
03/0300 | 17.9 | 88.2 | 990 | 60 | landfall 25 n mi north of Belize City, Belize |
05/1800 | 22.6 | 97.9 | 980 | 80 | landfall 20 n mi north of Tampico, Mexico |
Table 2.
Hurricane Keith selected surface observations, 28 September - 6 October 2000.
|
Minimum sea-level pressure |
Maximum surface wind speed (kt) |
|
Location |
Press. (mb) |
Date/ time (UTC) |
Sust. wind (kts) |
Peak gust (kts) |
Date/ timea (UTC) |
Storm surge (ft) |
Storm tide (ft) |
Rain (storm total) (in) |
Belize |
Philip Goodson Intl. Arpt., Belize | 994.0 | 01/0700 | 30 | 53 | 01/0400 | | | 32.67 |
| | | | | | | | |
Mexico |
Chetumal | | | | | | | | 9.65 |
Tampico | 990.0 | 05/1545 | 40 | 55 | 05/1445 | | | |
aDate/time is for sustained wind when both sustained
and gust are listed.
Table 2a.
Hurricane Keith supplemental rainfall observations, 28 September - 6 October 2000.
Station |
Storm-total rainfall (in) |
Belize |
Libertad | 7.46 |
Towerhill | 8.01 |
Central Farm | 10.41 |
Belmopan | 12.94 |
Barton Creek | 2.92 |
Chaa Creek | 6.56 |
Belize Zoo | 18.43 |
Melinda | 6.56 |
Middlesex | 10.00 |
Pomona | 6.47 |
Mayan King | 3.59 |
Savannah | 2.42 |
Bigfalls Plan. | 5.59 |
P.G.Agstat | 1.87 |
Blue Creek O.Walk | 17.64 |
Spanish Lookout | 9.85 |
Rum Point | 3.10 |
Consejo | 8.90 |
St Johns College | 24.69 |
Gallon Jug1 | 8.10 |
Gallon Jug2 | 8.20 |
Gallon Jug3 | 8.20 |
Gallon Jug4 | 9.60 |
Mexico |
Obregon | 8.35 |
Juan Serabia | 13.98 |
Sabinas | 14.43 |
Table 3.
Preliminary track forecast evaluation for Hurricane Keith - heterogeneous
sample. Errors in nautical miles for tropical storm and hurricane stages
with number of forecasts in parentheses. Numbers in bold italics represent
forecast which were better than the official forecast.
Forecast Technique |
Period (hours) |
12 | 24 | 36 | 48 | 72 |
CLIP | 31 (18) | 65 (14) | 127 (12) | 201 (11) | 298 (10) |
GFDI | 50 (18) | 94 (14) | 144 (12) | 191 (11) | 351 (10) |
GFDL* | 36 (18) | 72 (14) | 118 (12) | 169 (11) | 273 (10) |
GFNI | 36 (14) | 61 (12) | 89 (11) | 101 (9) | 119 (8) |
GFDN* | 25 (8) | 33 (6) | 68 (6) | 97 (6) | 136 (4) |
GFUI | 30 (8) | 55 (6) | 91 (5) | 139 (5) | 221 (9) |
GFDU* | 21 (5) | 37 (4) | 58 (3) | 82 (3) | 171 (3) |
AVNI | 52 (14) | 101 (13) | 157 (10) | 182 (6) | 398 (6) |
AVNO* | 62 (13) | 105 (12) | 151 (11) | 191 (7) | 421 (5) |
BAMD | 25 (17) | 56 (13) | 73 (11) | 130 (10) | 297 (10) |
BAMM | 35 (17) | 70 (13) | 118 (12) | 209 (11) | 454 (9) |
BAMS | 34 (18) | 72 (14) | 114 (12) | 217 (11) | 462 (10) |
NGPI | 35 (18) | 77 (14) | 96 (12) | 131 (11) | 208 (10) |
NGPS* | 39 (9) | 56 (7) | 99 (6) | 91 (5) | 207 (5) |
UKMI | 60 (18) | 132 (14) | 191 (12) | 255 (11) | 332 (10) |
UKM* | 60 (9) | 116 (7) | 194 (5) | 243 (5) | 357 (5) |
GUNS | 36 (18) | 72 (14) | 106 (12) | 147 (11) | 253 (10) |
A90E | 30 (18) | 50 (14) | 102 (12) | 174 (11) | 391 (10) |
A98E | 29 (18) | 51 (14) | 96 (12) | 163 (11) | 288 (10) |
A9UK | 28 (8) | 47 (6) | 109 (5) | 189 (5) | 400 (4) |
LBAR | 33 (18) | 100 (14) | 192 (12) | 279 (11) | 426 (10) |
VBAR | 32 (14) | 88 (11) | 173 (10) | 253 (9) | 244 (8) |
FSSE* | 51 (13) | 89 (12) | 130 (11) | 201 (10) | 263 (8) |
| | | | | |
NHC Official | 32 (18) | 73 (14) | 137 (12) | 214 (11) | 329 (10) |
NHC Official 10-Year Average (1990-1999) | 46 (2057) | 85 (1842) | 122 (1650) | 158 (1471) | 235 (1165) |
*Output from these models was unavailable at time of forecast issuance.
Table 4.
Watch and warning summary, Hurricane Keith, 28 September - 6 October 2000.
Date/Time (UTC) |
Action |
Location |
29/2100 | Hurricane Watch Issued | Yucatan Peninsula of Mexico from Chetumal to Cabo Catoche. |
30/1030 | Hurricane Warning Issued | Yucatan Peninsula of Mexico from the Mexico/Belize border to Cabo Catoche. |
30/1030 | Hurricane Watch and Tropical Storm Warning Issued | Belize from Belize City to the Mexico/Belize Border. |
30/1500 | Hurricane Watch Issued | Yucatan Peninsula of Mexico from Cabo Catoche to Progreso. |
30/1630 | Hurricane Warning Issued | Belize from Belize City to the Mexico/Belize Border. |
30/2100 | Hurricane Warning Issued | Belize from Belize City to Monkey River Town. |
03/0300 | Hurricane Warning changed to Tropical Storm Warning | Yucatan Peninsula of Mexico from the Mexico/Belize border to Cabo Catoche. |
03/0300 | Hurricane Watch changed to Tropical Storm Watch | Yucatan Peninsula of Mexico from Cabo Catoche to Progreso. |
03/0600 | Hurricane Warning changed to Tropical Storm Warning | Belize from Monkey River Town to the Mexico/Belize border. |
03/1500 | All Watches/Warnings Discontinued | |
04/1500 | Tropical Storm Watch Issued | Mexico from Coatzacoalcos to Matamoros. |
04/2100 | Hurricane Warning Issued | Mexico from Tuxpan to La Pesca. |
04/2100 | Hurricane Watch Issued | Mexico from north of La Pesca to Matamoros. |
04/2100 | Tropical Storm Warning Issued | Mexico from south of Tuxpan to Veracruz. |
05/0300 | Hurricane Warning Issued | Mexico from north of La Pesca to Matamoros. |
05/0300 | Hurricane Watch Issued | Mexico from south of Tuxpan to Veracruz. |
05/0300 | Tropical Storm Watch Issued | Texas from Brownsville to Port Mansfield. |
05/2100 | Hurricane Warning Continues | Mexico from north of Tampico to La Pesca. |
05/2100 | All Other Watches/Warnings Discontinued | |
06/0000 | Hurricane Warning changed to Tropical Storm Warning | Mexico from north of Tampico to La Pesca. |
06/2100 | Tropical Storm Warning Discontinued | Mexico from north of Tampico to La Pesca. |
Figure 1.
Best track for Hurricane Keith, 28 September - 6 October 2000.
Figure 2.
Best track minimum central pressure curve for Hurricane Keith, 28 September - 6 October 2000.
Figure 3.
Best track maximum sustained 1-minute 10 meter wind speed curve for
Hurricane Keith, 28 September - 6 October 2000.
Figure 4.
Hurricane track guidance for Hurricane Keith at 1200 UTC 2 October. Best
track line marked by hurricane and tropical storm symbols.