Summer 2003 Weather Story (Index) Above Normal Rains Just About Everywhere A Review of Summer 2003 in West Central and Southwest Florida One of many flood scenes on Florida's Suncoast during the wet summer of 2003. This photograph was taken in Charlotte County during torrential rains associated with Tropical Storm Henri in early September. Overview The rain came frequently, and often, in torrents, along the Suncoast during the Summer of 2003. The areal average of nearly 40 inches was similar to that for 2001, with the distribution reversed (heaviest rains near the coast in 2003) and without a true tropical cyclone. The frequency of heavy rain events near the coast was a direct response to a recurring deep southwesterly flow pattern, which didn't truly abate until September. This pattern likely increased the number of reported waterspouts compared with 2002, which also featured dozens of spouts. Individual periodic rain episodes produced widespread mainstem river floods, as well as pockets of freshwater flooding, throughout the summer. Three episodes in particular caused problems: June 18-23; August 7-11, and September 5-6. Prodigious rains in the Withlacoochee River basin from late June through mid August not only brought all stages of the river into flood, but helped maintain flood conditions for up to two consecutive months! Figure 1 shows actual rainfall; Figure 2 shows departure from normal. Some specific summer rainfall totals can be found here. Needless to say, areas affected hardest by freshwater and river flooding were those with the highest departures from normal, including portions of the north Suncoast (Citrus, Hernando, and Pasco Counties) and in the Manatee and Myakka River basins (Manatee and Sarasota Counties). Individual, brief monthly summaries follow. Figure 1. Total rainfall, June 1 through September 30. Figure 2. Total rainfall departure from 30 year climatic normals (1971-2000) for June through September, in 2003. Table 1. Abbreviated Flood Stage Report, NWS Tampa Bay, Summer, 2003. Crest values listed are the maximum for the listed basin between June 1 and September 30. With only one exception, these were the highest levels achieved thus far in 2003. River and Station Flood Stage Crest Stage (Ft) Date Peace R. at Arcadia 11 15.41 June 26 Horse Crk. at Arcadia 12 18.02 June 23 Peace R. at Bartow 8 8.32 June 25 Withlacoochee R. at Croom 9 9.66 August 27 Withlacoochee R. at Dunnellon 29 29.54 August 9 Anclote R. at Elfers 20 21.02 August 12 Withlacoochee R. at Holder 8 9.90 August 25 Alafia R. at Lithia 13 17.61* June 23 Myakka R. at Myakka State Park 7 12.46 June 24 Manatee R. at Myakka Head 11 20.85 June 22 Manatee Dam 41 42.42 June 22 Manatee R. at Rye Bridge 11 14.79 June 22 Withlacoochee R. at Trilby 12 13.95 August 24 Little Manatee R. at Wimauma 11 17.67 June 22 Cypress Crk. at Worthington Gardens 8 10.27 August 13 Peace R. at Zolfo Springs 16 17.71 June 25 * One higher value was recorded in January, 2003. Monthly Reviews June Prodigious rains north and south of Tampa A true nor'easter churning off the New England coastline on the 1st was a harbinger of upcoming weather along the entire United States eastern seaboard for June. West to southwest atmospheric winds maintained cool conditions over the north Atlantic states, and prevented the Bermuda High from becoming established until the very end. The high level west winds extended into Florida early in June, providing interludes of continental air, keeping widespread precipitation totals down. However, by the third week of June, high pressure finally developed east of the Bahamas, and soon after a southwest flow of deep tropical moisture developed in the eastern Gulf. An upper level disturbance sliding through the eastern U.S. around the 20th channelled the moisture from the eastern Gulf into the Suncoast, resulting in drenching rains and flooding between the 18th and 23rd. Above normal cloud cover kept daytime temperatures a bit cooler than normal, yet maintained warmer nights, with the result a mean temperature near normal for the month. Monthly rainfall is shown in Figure 3. July Just About Right The Bermuda High tried to establish itself this month, but was repeatedly flattened by continued west to northwest flow across the eastern seaboard. Areal rainfall ended up a bit below normal, but there were embedded wetter pockets, mainly north of the Tampa Bay area. A brief interlude of tropical moisture produced some heavy rains between the 12th and 14th, but high level northwest flow for the latter half of the month reduced precipitation a bit. Temperatures once again were about normal. Of interest in July were the number of waterspouts (over a dozen), and one F1 tornado in Hillsborough County. Monthly rainfall is shown in Figure 4. August Flooding: Round 2 West to southwest flow continued unabated into early August. By the second week, a deep upper level disturbance dipped into the northern Gulf, which once again channelled deep tropical moisture into the Suncoast. The result, once again, was torrential rains, this time a bit closer to the immediate coast, between August 7th and 11th. The disturbance loosened it's grip by mid month, and broad high pressure finally became established from the western Atlantic across the eastern U.S. by mid month. More typical afternoon and evening convection resulted, generally closer to the coast. The end result was above normal rainfall everywhere, with up to double the average in some spots near the coast. Monthly rainfall is shown in Figure 5. September T.S. Henri...then Quieter Barely there, Tropical Storm Henri was the main weather story just after Labor Day. However, the result was more typical of yet another channelled southwest flow event than a true tropical cyclone. Banded torrential rains affected Sarasota through Lee Counties on the 5th, with a potent convergent thunderstorm slamming southern Hernando County north of the ill-defined center after landfall early on the 6th. Thereafter, sinking air dominated much of the central and northern Florida peninsula, holding rainfall totals near or below normal. The story was somewhat different for southwest Florida. After Henri's bands dropped up to 8 inches of rain, a line of stationary afternoon thunderstorms pounded Lee and Charlotte County on the 13th, producing minor flooding. On the 25th, a stationary front and weak upper level disturbance in the northeast Gulf focused moisture across southwest Florida. Torrential rains and flooding pounded Naples (Collier County), with generally 2 to 4 inches affecting Lee County. When all was said and done, record rainfall occurred in parts of southwest Florida. Monthly rainfall is shown in Figure 6. Figures 3 through 6: West Central and Southwest Florida summer 2003 rainfall for June (far left), July (middle left), August (middle right), and September (far right). Click on each for a larger image.