Atmospheric River

This web site provides visualization products that assist in the ARs forecasting in southern South America (SA). The products are based on the Global Forecast System (GFS) model output from the National Center for Environmental Prediction (NCEP) of the USA. ARs are a long and narrow corridor with strong water vapor transport in atmosphere that produce heavy precipitation when they impact against the Andes mountains. Further information of ARs . here.

Products for AR forecasting derived from the GFS model

IWV

Integrated Water Vapor (kg/m2)

It is the Water Vapor content in the whole vertical column of the atmosphere. Variable also knows as Precipitable Water.

IVT

Integrated Vapor Transport (kg/m/s)

It is the horizontal water vapor flux integrated in the vertical column of the atmosphere from surface to 100 hPa.

Height-Latitude plots

Plots showing the horizontal water vapor transport at different vertical levels in the atmosphere along the 77°W meridian close to the west coast of SA. (more info).

Forecast of the AR condition categories on the west coast of South America

The AR conditions are forecasted by the GFS model on the west coast of southern South America according to the Ralph’s AR scale. The AR scale combine the magnitude of IVT and its duration to categorize the strength and impact of the AR conditions at fixed sites, being the category 1 the weakest with primarily beneficial impacts and the category 5 the strongest with primarily hazardous impacts.

Meteograms

Temporal series of forecasted IWV, IVT, 0°C isotherm, horizontal moisture flux and precipitation at different city locations of southern SA.

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