Abstract
Atmospheric rivers (AR) are long, narrow jets of moisture transport responsible for over  90% of moisture transport from the tropics to higher latitudes, covering only between  2% and 10% of the earth’s surface. ARs have a significant impact on the hydrological cycle of midlatitudes and polar regions, which has resulted in a large effort to study ARs  and their impacts on these regions. It is not until recently that ARs in tropical latitudes are starting to generate interest within the scientific AR community. We use the European Centre for Medium-Range Weather Forecasts (ECMWF) Atmospheric Reanalysis of the Twentieth Century (ERA-20C) dataset and the Bayesian AR detector Toolkit for Extreme Climate Analysis (TECA) Bayesian AR Detector (TECA–BARD) to show the relationship between extreme precipitation and ARs in central-western Mexico (CWM) during the dry seasons (November-March) in the 1900-2010 period. We find that more than 25% of extreme precipitation amount and frequency are associated with ARs, with a maximum of 60%-80% during December and January near the coast of Sinaloa (107.5°W,25°N).  Composites of the mean meteorological state show ”ideal” conditions for orographic precipitation due to landfalling ARs: high horizontal vapor transport perpendicular to the Sierra Madre. The horizontal vapor transport field and the tropospheric wave patterns in vertical velocity, surface pressure, and geopotential height indicate that these ARs are  related to tropical-extratropical interactions; however, this has yet to be quantified. Our results suggest that TECA–BARD reasonably estimates AR presence in CWM.