Source(s): I am a Meteorologist. Isolated thunderstorms are especially common during the summer in the mid-late afternoon when it is hot and humid. This is when you see those high towering, popcorn looking clouds in the middle of the afternoon when the sun hits the grounds and heats the air up. Usually isolated storms do not cover a large area.
Salmonella enterica serovar Typhimurium (S. typhimurium) causes enteric disease in humans. It is a food-and water-borne pathogen that can be easily disseminated in a population: for instance outbreaks of salmonellosis can occur by contamination of salad.
There are two commonly used strains of Salmonella typhi, CT18 and Ty2. Salmonella typhi CT18 has a large circular chromosome consisting of 4.8 Mb and two plasmids, pHCM1 and pHCM2, one of which has multiple drug resistance (pHCM1).