Preliminary Report
Hurricane Gert
14 - 21 September 1993

1993 PRELIMINARY REPORTS

Tropical Storm Arlene (TS)
Tropical Storm Bret (TS)
Tropical Storm Cindy (TS)
Tropical Storm Dennis (TS)
Hurricane Emily (3)
Hurricane Floyd (1)
Hurricane Gert (2)
Hurricane Harvey (1)

Gert was a large sprawling system which spent much of its lifetime near Central America and Mexico. It hit mainland Mexico with maximum sustained winds near 98 mph, but its biggest impact was caused by very heavy rainfall in Nicaragua, Honduras and especially in Mexico.

 

a. Synoptic History

A tropical wave passed off the west coast of Africa on 5 September well to the south of Dakar. The wave moved rapidly westward (near 23 mph) across the tropical Atlantic for the next several days at rather low latitudes, causing some enhancement of convection in the Intertropical Convergence Zone. The cloudiness associated with the wave became a little better organized as the system neared the Windward Islands, and a weak surface low associated with the wave passed over Trinidad on the 11th. Over the next couple of days, most of the system moved over the extreme northern part of South America. It emerged over the waters of the southwest Caribbean Sea late on the 13th. The upper tropospheric environment over this region was apparently favourable for development, and deep convection soon organized into curved bands. The system was classified as a T1.0 on the Dvorak scale by the NHC's Tropical Satellite Analysis and Forcast (TSAF) unit at 1200 UTC 14 September. The tropical depression stage of Gert begins at 1800 UTC on 14 September, about 90 nautical miles north of the north coast of Panama.

During the early stages of its existence it was clear that Gert had a fairly large-sized circulation. This was evident not only from satellite imagery, but also from rawinsonde data over the western Caribbean area. The depression strengthened to a tropical storm by 1200 UTC on the 15th, as the associated cloud patter continued to become better organized. Development was soon halted, as Gert's west-northwestward trek over the land mass of Nicaragua in the vicinity of Bluefields around 1800 UTC on the 15th. The center of Gert then began a nearly two-day northwestward trek over the land masses of Nicaragua and Honduras. The system weakened to a depression about six hours after moving inland over Nicaragua, but maintained enough of a surface circulation, over land, to retain depression status for the next 36 hours. This was at least partly attributable to the large diameter of Gert's circulation, that was able to maintain some contact with the adjacent Caribbean and Pacific waters.

The depression emerged over the Gulf of Honduras around midday on the 17th, and strengthened back to a tropical storm based on NHC satellite classifications and a ship report. Gert was moving north-northwestward at this time. The northwest and northwestward motion was apparently brought about by a mid- to upper-tropospheric cyclone over the eastern Gulf of Mexico. By 0000 UTC on th 18th, Gert was moving inland again near Belize City, Belize, its time over water being of such duration that it did not strengthen beyond minimum tropical storm intensity. A mid-tropospheric ridge over the northwestern Guf of Mexico area forced Gert to turn back toward the west-northwest, and Gert, having weakened back to a depression, crossed the Yucutan Peninsula on the 18th. The center re-emerged over water, this time over the Bay of Campeche, late on that day.

Now that the center was over relatively open waters, the opportunity for significant strengthening existed. Gert re-intensified to a tropical storm by 0600 UTC on the 19th, and 24 hours later it became a hurricane. The forward motion slowed to less than 6 mph around 0000 UTC on the 20th, which allowed more time for the center to dwell over the warm waters of the southwest Guf of Mexico. Consequently, Gert was able to strengthen maximum intensity of around 98 mph just before making its third landfall; U.S. Air Force Reserve Unit reconnaissance reports indicate that the central pressure fell to 970 mb. The eye of Gert, moving westward (or even a little south of west), crossed the coast of mainland Mexico just to the north of Tuxpan near 2100 UTC on 20 September. A portion of the southern eyewall passed over Tuxpan around 2000 UTC. After moving inland, the center accelerated westward. Gert weakened rapidly over the Sierra Madre Oriental mountains of Mexico, and the cyclone was reduced to a tropical depression just after 0600 UTC on the 21st. However, the fast-moving circulation was able to remain intact while crossing Mexico, and the center neared the pacific coast of Mexico around 1800 UTC on the 21st. It emerged over the eastern Pacific waters shortly thereafter, where it was reclassified as Tropical Depression Fourteen_E.

b. Meteorological Statistics

No quantitive wind reports were received from Nicaragua. Chetumal, Mexico reported winds to near 44 mph, presumably in gusts around the time that Gert was making landfall near Belize (just to the south). Tuxpan, Mexico reported winds to 102 mph, Poza Rica (about 25 nautical miles south of Tuxpan) reported winds to near 81 mph, and Tampico reported winds to near 58 mph. It is not known if these were peak gusts or sustained values, but the former appears more likely.

1. Rainfall Data

Gert dumped copious amounts of rainfall over portions of Central America. Tegucigalpa, Honduras reported 6.77 inches for the 24-hour period ending 1200 UTC 18 September. A 24-hour rainfall total of 7.40 inches was reported from Chetumal, Mexico (state of Quintana Roo) for the same period. However, the most massive rainfall amounts were recorded after Gert made its third landfall, where the broad circulation made contact with the eastern slopes of the Sierra Madre Oriental highlands of Mexico. Tanzabaca, Gallinas and Tierra Blanca (all in the state of San Luis Potosi) reported rainfall amounts of 16.80, 12.83, and 12.70 inches, respectively, for the 24-hour period ending near 1800 UTC 21 September. Tempoal and El Higo (state of Veracruz) measured 13.35 and 10.47 inches, respectively, for the same period. In contrast, Tuxpan (also in Veracruz), near the coast and in the eyewall, but mostly removed from orographic effects, reported 5.81 inches for the same 24-hour period.

c. Casualty and Damage Statistics

There were 76 deaths attributed to Gert; 42 in Mexico, 21 in Honduras, 8 in Nicaragua, 4 in El Salvador and 1 in Costa Rica.

Figures are sketchy on the total number of homeless due to Gert in Central America, but 100,000 apears to be a conservative figure. Damage totals are incomplete. The government of Mexico reported that 29,075 homes were damaged or destroyed and 145,000 acres of crops were destroyed, with a total damage estimate of about $156 Million in Mexico. At least $10 Million reportedly occurred in Honduras, mainly in the northern part of the country. Reports of "considerable" damage to roads, by rain and mud slides, were received from Nicaragua