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Context. A recent, detailed study of the well-known solar wind disappearanceevent of 11 May 1999 traced its origin to a coronal hole (CH) lying adjacent toa large active region (AR), AR8525 in Carrington rotation 1949. The AR waslocated at central meridian on 05 May 1999 when the flows responsible for thisevent began. We examine the evolution of the AR-CH complex during 5-6 May 1999to study the changes that apparently played a key role in causing thisdisappearance event. Aims. To study the evolution of the solar source region ofthe disappearance event of 11 May 1999. Methods. Using images from the SoftX-ray Telescope (SXT), the Extreme-ultraviolet Imaging Telescope (EIT) and theMichelson Doppler Imager (MDI) to examine the evolution of the CH and ARcomplex at the source region of the disappearance event. Results. We find adynamic evolution taking place in the CH-AR boundary at the source region ofthe disappearance event of 11 May 1999. This evolution, which is found toreduce the area of the CH, is accompanied by the formation of new loops in EUVimages that are spatially and temporally correlated with emerging flux regionsas seen in MDI data. Conclusions. In the period leading up to the disappearanceevent of 11 May 1999, our observations, during quiet solar conditions and inthe absence of CMEs, provide the first clear evidence for Sun-Earth connectionoriginating from an evolving AR-CH region located at central meridian. With theexception of corotating interacting regions (CIR), these observations providethe first link between the Sun and space weather effects at 1 AU, arising fromnon-explosive solar events.

The solar wind disappearance event of 11 May 1999: source region evolution