National Weather Service
South Florida Forecast Office
Miami, Florida

Hurricane Katrina Preliminary Post Storm Report issued by NWS Miami
List of Products Issued by NWS Miami Throughout the Event

    A tropical wave that moved across the Atlantic from near the west coast of Africa eventually spawned the tropical cyclone that became Hurricane Katrina. The tropical wave became a tropical depression near the central Bahamas late on August 22. The depression moved slowly northwest and became Tropical Storm Katrina on August 24 near the northwest Bahamas then turned west and intensified to a hurricane on August 25, a few hours before making landfall. Figure 1 shows a satellite picture of Katrina as it was intensifying across the Southeast Florida coastal waters the afternoon of August 25.


Figure 1. Satellite image from 25 August at 12:32 pm EDT. Then Tropical Storm Katrina was intensifying and developing an eye as it moved west across the very warm waters of the Gulf Stream toward a landfall near the Broward-Miami-Dade county line. Click on picture for a larger version.

    The center of the ragged 25 mile-wide eye of Katrina made landfall along the southeast Florida coast around 6:30 PM, Thursday, August 25 near the Broward/Miami Dade county border then moved toward the southwest across central and southwest Miami Dade county, passing directly over the National Weather Service (NWS) Office in Sweetwater. Katrina weakened to a Tropical Storm before exiting the Florida peninsula into the Gulf of Mexico early on August 26 just north of Cape Sable in Mainland Monroe county then quickly regained hurricane strength in the southeast Gulf of Mexico. The distribution of winds and rain near the center of Katrina while passing across South Florida was asymmetrical with the strongest winds and heaviest rain located to the south and east of the center.  Figure 2 illustrates radar loops of the reflectivity (rain) and base velocities associated with Hurricane Katrina as it moved across South Florida. Figure 3 illustrates the actual track of the center with time labels as it moved across the area.


Figure 2. Radar reflectivity (left) and velocity (right) images valid at 631 PM EDT (around the time hurricane Katrina was making landfall on the southeast Florida coast). Click on image for a larger version of the image. For a radar loop of Katrina moving across Broward and Miami Dade Counties (11 MB FILE), click on reflectivity or velocity.



Wind Observations

    Measurements from reconnaissance aircraft and Miami Doppler Weather Radar (Fig. 2) estimated maximum sustained winds to be 80 mph. The maximum reported sustained wind over the South Florida peninsula was 75 mph measured atop a building at the University of Miami Rosentiel School of Marine and Atmospheric Science (RSMAS) on Virginia Key. This wind value was determined by adjusting the actual wind speed to the standard anemometer height of 10 meters. This same site recorded an unadjusted peak wind gust of 94 mph. The anemometer atop the Miami Weather Forecast Office in Sweetwater measured a sustained wind of 69 mph. Maximum sustained winds measured at NWS Automated Surface Observing System (ASOS) sites included 60 mph at Fort Lauderdale-Hollywood International Airport, 50 mph at Tamiami Airport in West Kendall and 48 mph at Miami International Airport.

    The maximum ASOS measured peak wind gusts included 82 mph at Fort Lauderdale International Airport, 78 mph at Miami International Airport, and 76 mph at Tamiami Airport in West Kendall. Other unofficial wind gust measurements included 97 mph at Homestead General Airport, 92 mph at Port Everglades, 87 mph at the Miami NWS Office in Sweetwater, 77 mph at Marco Island, 76 mph at the NOAA facility on Virginia Key, and 64 mph at Boca Raton Airport. The minimum pressure measured over the South Florida peninsula was 983.1 millibars at the NWS site in Sweetwater.

    Figure 4 shows a graphic of the wind gust recorder from WFO Miami and Fig. 5 shows the barograph trace as the system moved over the NWS/NHC building. As mentioned earlier, the highest wind gust at WFO Miami was 76 knots or 87 mph (the wind gust recorder experiences pin drag, and therefore 4 knots must be added to the trace) and the lowest pressure was 983.1 millibars (mb).






More detailed wind data can be found in Hurricane Katrina Preliminary Post Storm Report issued by NWS Miami.

Storm Rainfall Totals

    Since Katrina was expected to be a very slow moving storm, NWS forecasts called for 6 to 12 inches of rainfall generally across South Florida with local amounts as high as 15 to 20 inches. Comparisons of the expected impact of Katrina were used with Hurricane Irene in 1999, when over 16 inches of rain fell, and the tropical disturbance of October 2, 2000, which inundated metro Miami-Dade County with nearly 15 inches of rain.  However, Katrina moved south of the forecast track, turning southwest across Miami-Dade County and Everglades National Park, which shunted the heaviest rainfall south of a line from Key Biscayne across Coral Gables to Kendall and Homestead while the rest of South Florida generally received less than the forecast rainfall amounts.  Rainfall amounts were extremely heavy across portions of South Miami-Dade county causing flooding of structures, vehicles, and crop land. A maximum storm total amount of 16.33 inches was measured by a cooperative observer in Perrine. Other heavy amounts in South Miami-Dade county included 14.04 inches at Homestead Air Reserve base, 12.25 inches near Florida City and 11.13 inches near Cutler Ridge. Most of the remainder of Miami-Dade and all of the metropolitan areas of Broward and Palm Beach counties generally received amounts of two to four inches. Rainfall over interior South Florida ranged from one to three inches with mostly less than one inch over coastal Collier county. Figure 6 illustrates  radar estimated storm total precipitation for the period extending from around 9 PM EDT Wednesday August 24 to 6 PM EDT Friday August 26.

    Flood Warnings were issued at least 6 hours before initial reports of flooding were received across South Miami Dade county.


Other storm rainfall totals across South Florida can be found in Hurricane Katrina Preliminary Post Storm Report issued by NWS Miami.

Hurricane Katrina left the southwest florida coast  across central portions of Mainland Monroe county between Everglades City and Cape Sable. This resulted in the highest storm tide across South Florida being observed in the Cape Sable area, and especifically in the Flamingo area. Reports from Everglades National Park indicate storm tide in the Flamingo area was as high as 3 to 5 feet. The surge started coming in around 1 AM EDT on August 26 with the maximum observed around dawn. The storm tide stayed high through around mid morning as the astronomical high tide was around 8 AM EDT. Six trailers were damaged with one completely destroyed by the surge. Park officials reported water damage in lower level of ranger living quarters. Seven personal and eleven government vehicles were flooded. Figure 7 illustrates a simulation of the storm tide provided by TPC/NHC which was verified by the reports obtained from Everglades National Park:

Figure 7. NHC/TPC Storm Tide simulation for Katrina across portions of South Florida in feet. Notice highest surge in the Cape Sable/Flamingo area as reported also by Everglades National Park.

    A total of six persons are known to have died directly as a result of the effects of winds and water in South Florida. Three of the deaths, all in Broward county, were associated with trees or tree limbs that were blown down. The other three deaths, all in Miami-Dade county, were associated with drownings, two on boats and one under unknown circumstances. In addition at least another six people died from indirect hurricane effects including three from carbon monoxide poisoning caused by generators, one in a vehicle accident, one during debris cleanup and one associated with lack of electricity. Several people were injured, including a number related to carbon monoxide poisoning.

    Preliminary damage estimates include 100 million dollards in damage and 423 million dollars in agricultural losses.