Mobile and smart devices have the potential to form part of Grid infrastructures. These devices can serve two important functions in Grid environment either as service consumer or as valuable service providers. However, there are a number of challenging issues in using a mobile device as service consumer in Grid systems when this fluctuating mobile environment is taken into consideration. Intermittent connectivity, bandwidth fluctuations, high response time between service request and delivery, device heterogeneity and weak security among others. Among these, this paper focuses on modeling a context aware solution to address the problem of high response time in this environment which is caused by some execution context variations. A model of an adaptation mechanism is proposed that monitors execution context of the Grid clients, it evaluates the monitored contexts and decides on what reconfiguration decision to take. The overall impact is to reduce the time between when a service request is made and when the service is delivered to mobile clients.