Tropical Storm Selma formed south of El Salvador on Friday morning. At 11:00 a.m. EDT on Friday the center of Tropical Storm Selma was located at latitude 11.1°N and longitude 89.5°W which put it about 180 miles (290 km) south of San Salvador, El Salvador. Selma was moving toward the northwest at 5 m.p.h. (8 km/h). The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h). The minimum surface pressure was 1005 mb.
A Tropical Storm Warning has been issued for the entire coast of El Salvador. A Tropical Storm Watch has been issued for the entire Pacific Coast of Guatemala.
A distinct low level center of circulation formed in a larger area of thunderstorms south of El Salvador on Friday morning and the National Hurricane Center designated the system as Tropical Storm Selma. The circulation of Tropical Storm Selma is very asymmetrical. Most of the showers and thunderstorms are located in the western half of the circulation. There are bands of showers in the eastern half of the circulation. An upper level ridge centered over the Yucatan Peninsula is producing easterly winds which are blowing over the top of the circulation. Those winds are causing moderate vertical wind shear which is the primary reason for the asymmetrical structure of the circulation. Selma is a small tropical storm. Winds to tropical storm force only extend out about 45 miles (75 km) from the center of circulation.
Tropical Storm Selma will be moving through an environment that is neutral for intensification. Selma will move over water where the Sea Surface Temperature is near 29°C. The upper level ridge will continue to cause moderate vertical wind shear. The shear will inhibit further intensification. If the upper level winds weaken, then some intensification may be possible. However, if the upper level winds get stronger, then Selma could weaken to a tropical depression.
A large counterclockwise circulation centered over Nicaragua and Honduras is steering Tropical Storm Selma slowly toward the northwest and the general motion is expected to continue on Friday. The upper level ridge over the Yucatan Peninsula will weaken on Saturday and that will allow Tropical Storm Selma to move more toward the north. On its anticipated track Tropical Storm Selma will make landfall on the coast of El Salvador or Guatemala on Saturday.
Tropical Storm Selma will bring some gusty winds to the coast. However, locally heavy rain and flash floods will be the primary risks associated with Tropical Storm Selma when it makes landfall.