Given the following context:

The St. Johns River lies within a humid subtropical zone. In summer months, the temperature ranges from 74 and 92 °F (23 and 33 °C), and between 50 and 72 °F (10 and 22 °C) in the winter, although drops may occur in winter months to below freezing approximately a dozen times. Water temperatures in the river correlate to the air temperatures. The average range of water temperatures is between 50 and 95 °F (10 and 35 °C), rising in the summer months. Where the river widens between Palatka and Jacksonville, wind becomes a significant factor in navigation, and both whitecap waves and calm surface waters are common.Rain occurs more frequently in late summer and early fall. Tropical storms and nor'easters are common occurrences along the Atlantic coast of Florida; the St. Johns River lies between 10 and 30 miles (16 and 48 km) inland, so any storm striking the counties of Indian River north to Duval produces rain that is drained by the St. Johns River. Tropical Storm Fay in 2008 deposited 16 inches (410 mm) of rain in a 5-day period, most of it located near Melbourne. The St. Johns near Geneva in Seminole County rose 7 feet (2.1 m) in four days, setting a record. The river near Sanford rose 3 feet (1 m) in 36 hours. Fay caused severe flooding in the middle basin due not only to the deluge but the flat slopes of the river. Typically, however, the St. Johns basin receives between 50 and 54 inches (1,300 and 1,400 mm) of rain annually, half of it in summer months. The rate of evapotranspiration corresponds to rainfall, ranging between 27 and 57 inches (690 and 1,450 mm) a year, most of it occurring in the summer.

answer the following question:

What is the full name of the place that widens between Palatka and Jacksonville, wind becomes a significant factor in navigation? 

St. Johns Rive