Gordon became a category one hurricane on the Saffir-Simpson Hurricane Scale
over the eastern Gulf of Mexico, but eventually made landfall in the Florida
Big Bend area as a weakening tropical storm.
a. Synoptic History
A tropical wave moved off the west coast of Africa on 4 September and
tracked westward across the tropical Atlantic. Little or no deep convection
was associated with the wave until 8 September when the wave was located
about 600 n mi east of the Lesser Antilles. The tropical wave moved through
those islands on 9-10 September bringing locally heavy rainfall and wind
gusts of 25 to 30 kt. The wave tracked west-northwestward and developed
centralized convection near the vorticity center over the central Caribbean
Sea on the 12th.
Satellite classifications from the Tropical Analysis and Forecast Branch
(TAFB) and the Satellite Analysis Branch (SAB) began around 0000 UTC 13
September. They indicated the convection was poorly organized. However, by
1800 UTC surface observations indicated a broad low pressure area had
developed along the wave axis about 100 n mi southeast of Cozumel, Mexico.
At 0000 UTC 14 September, Dvorak satellite intensity estimates from the TAFB,
SAB, and the Air Force Weather Agency (AFWA) suggested the broad low
pressure system was near tropical depression strength, but the overall
convective pattern was still poorly organized.
Tropical Depression Eleven formed about midway between Cozumel and Chetumal,
Mexico on the morning of 14 September based on a U. S. Air Force Reserve
(USAFR) reconnaissance aircraft report of a broad closed circulation and 31
kt flight-level (1500 ft) winds. By 2100 UTC, the depression's low-level
center had moved inland over the eastern Yucatan Peninsula, while the more
pronounced mid-level circulation was located about 10 n mi to the northeast.
This decoupled pattern persisted for more than 24 hours while the depression
tracked slowly northwestward across the northern Yucatan Peninsula.
Late on 15 September, an Air Force Reserve reconnaissance aircraft indicated
the depression had moved off the north coast of the Yucatan and over the
warm waters of the Gulf of Mexico. Aircrew reported the low- and mid-level
circulations had become vertically aligned, 59 kt flight-level (1500 ft)
winds, and a minimum pressure of 1003 mb. At 0000 UTC 16 September, the
depression had strengthened into Tropical Storm Gordon. Once over the warm
Gulf waters, Gordon moved steadily northeastward toward the Florida Big Bend
area and slowly intensified. A report of easterly winds of 64 kt from ship
MYMX5 located about 30 n mi northeast of the center indicated that Gordon
had become a hurricane by 0000 UTC 17 September. Only slight strengthening
continued for another 6 hours and Gordon eventually peaked at 70 kt.
is a NEXRAD/WSR-88D radar image at 0803 UTC 17 September, from Tampa Bay,
Florida (KTBW) when Gordon was near its peak strength.
After peaking on the 17th about 165 n mi southwest of Tampa,
Florida, slow weakening began as moderate southwesterly upper-level winds
ahead of an approaching mid-tropospheric trough began to increase the
vertical shear across the hurricane. Water vapor imagery and surrounding
upper-air data indicated that mid-level dry air entrainment from the south
also helped the weakening process. The dry air helped erode the outer cloud
and precipitation shield and gradually wrapped into the inner core of the
hurricane. This is depicted in Figure 1
by the large rain-free or "dry slot"
area located in the eastern semicircle between the eye and the outer
convective bands near the Florida west coast. Within a few hours, the dry
slot had worked its way counter-clockwise completely around the eye and by
1328 UTC reconnaissance reports indicated the minimum surface pressure had
risen sharply to 990 mb.
Gordon was downgraded to a tropical storm at 1800 UTC 17 September. It
continued to track northeastward and eventually made landfall just northwest
of Cedar Key, Florida, at 0300 UTC 18 September, as a tropical storm with 55
kt winds. After landfall, interaction with land and cool, stable air north
of a weak frontal boundary hastened the weakening process. At 1200 UTC the
same day, Gordon weakened into a tropical depression. By 1800 UTC, it merged
with the front and extratropical transition occurred over southeast Georgia.
Gordon's remnant low-level circulation then moved northeastward up the east
coast of the United States for the next 3 days before being absorbed by a
large extratropical low pressure system over eastern Canada around 1200 UTC
21 September. Owing to the lack of any significant baroclinic effects, only
modest rainfall totals and no significant flooding were observed over the
mid-Atlantic and northeast regions of the United
b. Meteorological Statistics
lists the best track positions and intensities of Gordon at six-hour
intervals. Figure 2
is a display of this track. Observations in Gordon
(Figure 3 and Figure 4)
include satellite-based Dvorak technique intensity estimates
from TAFB, SAB, and AFWA. In addition, flight-level observations were
available from flights of the USAFR 53rd Weather Reconnaissance
Squadron and the NOAA Aircraft Operations Center.
As a result of Gordon weakening well offshore the Florida west coast, only a
few reports of tropical storm force winds were received.
Table 2 and Table 3
consist of all ship and buoy reports, respectively, of tropical storm force
winds (> 34 kt) associated with Hurricane Gordon.
Table 4 consists
of selected surface reports from Automated Surface Observing System (ASOS)
and Coastal-Marine Automated Network (C-MAN) observation stations from
Florida for Hurricane Gordon.
During Gordon's intensification stage, the maximum reconnaissance flight
level (850 mb) wind measured was 89 kt (71 kt surface wind using an
adjustment factor of 80%) at 0544 UTC 17 September, whereas the minimum
surface pressure of 981 mb was observed at 0805 UTC -- 11 mb
lower than the pressure when the maximum wind was observed.
Dry air entrainment further reduced the amount of rainfall that typically
occurs with a land falling tropical cyclone moving at a forward speed of 10
to 12 kt. The largest rainfall amounts were reported in Florida and ranged
from 4.83 in at Cedar Key on the west coast to 3.02 in at Vero Beach
on the east coast. No significant flooding was reported.
Gordon's weakened state also reduced the amount of storm surge flooding that
otherwise could have occurred. Maximum storm tides (i.e., water height above
National Geodetic Vertical Datum [1929 mean sea level]) occurred along the
Florida west coast and generally ranged from 3 to 5 ft from the Tampa Bay
area northward to Cedar Key.
c. Forecast and Warning Critique
There are no error statistics available at 72 h due to the short time period
that Gordon existed as a tropical storm or hurricane. Average official track
errors for Gordon (with the number of cases in parentheses) were 32 (8), 37
(6), 40 (4), and 75 (2) n mi for the 12, 24, 36, and 48 h forecasts,
respectively. These errors are significantly lower than the average
official track errors for the 10-yr period 1990-1999 (46, 85, 122, and 158 n
mi, respectively) at all times. The official forecast errors were better
than all available forecast guidance at all times, except slightly worse
than the CLIPER (CLImatological and PERsistence) model at 12 h and the
GFDL model at 48 h.
Average official intensity errors for Gordon were 8, 9, 20, and 18 kt for
the 12, 24, 36, and 48, respectively. Unlike the track errors, the intensity
errors were greater than the average official errors for the 10-yr period
1990-1999 (7, 11, 13, and 16 kt, respectively), and were over-forecasts at
all times, especially at 36 and 48 h. The SHIPS (Statistical Hurricane
Intensity Prediction Scheme) intensity forecast model had similarly poor
lists watches and warnings issued for Hurricane Gordon.
d. Casualty and Damage Statistics
There were 23 deaths reported in Guatemala due to heavy rainfall-induced
flooding in mountainous areas. Many of the deaths may have occurred during
the pre-depression stage while the system was moving slowly over the western
Caribbean Sea and Yucatan Peninsula of Mexico. One death occurred in the
United States when a surfer drowned in heavy seas near Pensacola, FL while
Gordon make landfall in the Florida Big Bend area.
Most of the damage was due to downed tree and power lines. In addition, more
than 20,000 Florida customers lost power for more than six hours during
Gordon's passage. Also, numerous homes along the immediate Florida west
coast from the Tampa Bay area northward to Cedar Key experienced some minor
roof damage. Some coastal roads and highways experienced flooding from the
storm surge and had to be temporarily closed. Damage estimate for the United
States is $10.8 million. No damage estimates have been received from
Guatemala in association with the heavy
rainfall and flooding.
There were also two confirmed tornadoes. The first tornado (intensity
unknown) occurred around 1845 UTC 17 September, in Cape Coral along the
Florida west coast. At least 1 home received major damage and 2 other homes
received minor damage. A second tornado (F0) touched down later that down
around 2030 UTC near the town of Ponce Inlet in Volusia County along the
Florida east coast. Damage was minimal and mainly confined to downed trees
and power lines, although a few homes received minor damage.
0803 UTC, 17 September 2000, NEXRAD/WSR-88D Base Reflectivity (0.5o elev.)
radar data from Tampa Bay (KTBW), Florida. Image is at approximately the
same time the minimum pressure of 981 mb was observed. Eye is located about
140 n mi west-southwest of the radar site at an altitude of approximately
22,000 ft ASL.
Best track for Hurricane Gordon, September 2000.
|Lat. (°N)||Lon. (°W)
|17/0600||26.1||84.9||981||70|| " |
|17/1800||28.0||83.8||985||60||tropical storm |
|18/0600||29.8||83.0||1000||40|| tropical storm |
|21/1200|| ||absorbed by extratropical low|
|17/0600||26.1|| 84.9|| 981||70||minimum pressure|
|18/0300||29.3||83.2||991||55||landfall near Cedar Key, Florida|
Ship reports with winds of at least 34 kt for Hurricane Gordon.
|Ship Call Sign
Buoy reports with winds of at least 34 kt for Hurricane Gordon.
|Buoy Call Sign
|17/0020 ||42003||25.9||85.9|| 345/43(57b)|| 999.6|
|17/0200 ||42003||25.9||85.9|| || 998.5|
|17/1800 ||42036||28.5||84.5||010/37 ||1005.5|
|17/2000 ||41009||28.5||80.2||130/35 b||1010.8|
|17/2100 ||42036||28.5||84.5|| 340/37(41b)||1003.8|
|18/0900 ||41004||32.5||79.1||090/35 b|| |
* 8-min average wind, moored buoys
alast of several occurrences
Selected surface observation reports (ASOS and C-MAN stations) from Florida for
|Maximum surface wind speed
(mb) [Date/Time, if different]
|17/1529||St. Petersburg (KSPG)||130/38|| || |
|17/1552||Punta Gorda (KPGD)||160/32|| || |
|17/1650||Titusville (KTTS)||150/15||30|| 1011.8 [17/2250]|
|17/1800||St. Petersburg (KPIE)||180/39|| || |
|18/1855||Patrick AFB (KCOF)||120/27||39|| |
|17/1908||Leesburg (KLEE)||130/35|| || |
|18/0015||Keaton Beach (KTNF1)|| ||36|| 1003.7 [18/0500]|
|18/0110||Cedar Key (CDRF1)|| 110/45a||59|| 999.3 [18/0300]|
|18/0229||Cross City (KCTY)||040/29||37|| 997.6 [18/0543]|
|18/0242||Perry-Foley (K40J)||360/24||34|| 1005.1 [18/0612]|
|18/0540||St. Augustine (SAUF1)||160/32a||40|| 1008.2 [18/0900]|
|18/0604||Gainesville (KGNV)|| || ||1004.4 |
|18/1302||Jacksonville (KCRG)|| ||36|| |
*2-min average wind
a10-min average wind
Best track positions for Hurricane Gordon. Track during the extratropical
stage is based on analyses from the Tropical Analysis and Forecast Branch
and the NOAA Hydrometeorological Prediction Center.
Best track maximum sustained surface wind speed curve for Hurricane Gordon,
and the observations on which the best track curve is based. Aircraft
observations have been adjusted for elevation using 90%, 80% and 85%
reduction factors for observations from 700 mb, 850 mb and 1500 ft,
respectively. Estimates during the extratropical stage are based on
analyses from the Tropical Analysis and Forecast Branch and the NOAA
Hydrometeorological Prediction Center.
Best track minimum central pressure curve for Hurricane Gordon, and the
observations or estimates on which the best track curve is based. Estimates
during the extratropical stage are based on analyses from the Tropical
Analysis and Forecast Branch and the NOAA Hydrometeorological Prediction
Watch and warning summary for Hurricane Gordon, September 2000.
|16/0300||Hurricane Watch Issued||Florida west coast from Bonita Beach northward to the Suwanee River|
|16/1500||Tropical storm warning issued||Florida west coast from Bonita Beach northward to the Suwanee River|
|16/1500||Hurricane watch extended||Florida west coast from Suwanee River northward and westward to Apalachicola|
|17/0300||Hurricane warning issued||Florida west coast from Anna Maria Island to Ochlockonee River|
|17/0300||Tropical storm warning||Florida west coast from Bonita Beach northward to south of Anna Maria Island, and from west of Ochlockonee River westward to Indian Pass|
|17/0300||Tropical storm watch issued||Florida northeast coast and Georgia southeast coast from Flagler Beach, Florida northward to Brunswick, Georgia|
|17/0900||Tropical storm watch upgraded to tropical storm warning||Southeast U.S. coast from Flagler Beach, Florida northward to Brunswick, Georgia|
|17/0900||Tropical storm watch issued||Brunswick, Georgia northward to the South Santee River, South Carolina|
|17/1500||Tropical storm warning extended||Southeast U.S. coast from Flagler Beach, Florida northward to Little River Inlet, South Carolina|
|17/1500||Tropical storm watch extended||north of Little River Inlet, South Carolina to Cape Hatteras, North Carolina|
|17/1800||Tropical storm warning extended||Florida east coast from Flagler Beach south to Titusville|
|17/2100||Hurricane warning downgraded to tropical storm warning||Florida Gulf Coast from Anna Maria Island northward to Indian Pass|
|17/2100||Tropical storm warning discontinued||Florida west coast south of Anna Maria Island|
|17/2100||Hurricane watch discontinued||Florida Gulf Coast|
|18/0000||Tropical storm watch extended||Cape Hatteras, North Carolina northward to the North Carolina-Virginia Border, including Albemarle and Pamlico Sounds|
|18/0300||Tropical storm warning discontinued||Florida Gulf Coast west of Saint Marks and south of Anclote Keys|
|18/0300||Tropical storm warning discontinued||Florida east coast south of Flagler Beach|
|18/0900||Tropical storm warning discontinued||All of Florida Gulf Coast |
|18/0900||Tropical storm watch discontinued||All of North Carolina coast |
|18/1200||Tropical storm warning discontinued||All coasts of North Florida, Georgia, and South Carolina|