I think it unlikely you would be in serious trouble (from EMP) in the scenario you described given the distances involved. The serious EMP effects from nuclear weapons occur when detonation takes place at very high altitudes, the gamma radiation passes through the earths atmosphere, physics takes place and the EMP is generated. For low-yield, tactical weapons, detonation is more likely to occur near the ground and due to the yield involved the effects will be less severe. Yields and altitudes are unlikely to exceed those used in the only two examples we have of real world nuclear weapon usage (Hiroshima/Nagasaki), and even then the EMP that was generated would likely only effected a modern airliner if the aircraft was very close to the point of detonation to the extent that it would probably have been catastrophically damaged by the blast/heat wave.