During an el niño year, there is increased precipitation in the southern united states, but the north is warmer and dry. where does the moisture causing the precipitation in the south come from?

The moisture causing the precipitation in the southern United States during the El nino year is from the Pacific ocean. During an El nino event, the surface water in the central and eastern pacific ocean becomes significantly warmer than usual and it also reduced the up-welling of the cooler, which is also nutrient rich water from the deep which results in the shutting down or reversing the oceanic currents along the southern United states which results in precipitation in the south.