<p>The dynamic of rangelands results from complex interactions between vegetation, soil, climate, and human activity. In arid and semiarid areas, rainfall coefficients of variability are over 30 %. This scenario makes rangeland's condition challenging to monitor, and degradation assessment should be carefully considered to study grazing pressures. In the present work, we study the interaction of vegetation and soil moisture in arid rangelands, using vegetation and soil moisture indexes. We aim to study the feasibility of using water soil moisture (soil drought) as a warning index for vegetation drought. An arid agricultural region in the southeast of Spain, in the province of Almeria (Los V&eacute;lez), was selected for this study.</p> <p>MODIS images, with 250 and 500 m spatial resolution, from 2002 to 2019, were acquired to calculate the anomaly (Z-score) for the Vegetation Condition Index (<em>Z_VCI</em>) and the Water Condition Index (<em>Z_WCI</em>). ZVCI was calculated using the Normalised Difference Vegetation Index (NDVI). Soil moisture component (W) was obtained using the Optical Trapezoid Model (OPTRAM). The probability of coincidence of their negative anomalies between <em>Z_VCI</em> and <em>Z_WCI</em>, with lags between them, was calculated. The results show that for specific seasons, the anomaly of the water content index had a strong probability of informing in advance where the negative anomaly of VCI will decrease. Soil water content and vegetation indices show more similar dynamics in the months with lower temperatures (from autumn to spring). In these months, given the low temperatures, precipitation leads the vegetation growth. In the following months, water availability depends on evapotranspiration and vegetation type as the temperature rises and the precipitation falls. The stronger relationship between precipitation and vegetation from autumn to the beginning of spring is reflected in the feasibility of <em>Z_WCI</em> to aid the prediction of vegetation index anomalies. During these months, using <em>Z_WCI</em> and <em>Z_VCI</em> as warning indices are possible for two Spanish semiarid rangeland areas: Los V&eacute;lez (Almer&iacute;a) and Bajo Arag&oacute;n (Teruel). Particularly, November to January showed an average increase of 20&ndash;30 % in the predictability of vegetation index anomalies. We find other periods of relevant increment in the predictability as March and April for Los V&eacute;lez, and July, August and September for Bajo Arag&oacute;n.</p>