tn The preterite with the vav (ו) consecutive is here subordinated to the next clause in view of the emphasis put on the subject, Yahweh, by the disjunctive word order of that clause.
tn By starting the clause with the subject (an example of disjunctive word order) the text is certainly stressing that Yahweh alone did this.
sn This clause has been variously interpreted. Lightning would ordinarily accompany thunder; in this case the mention of fire could indicate that the lightning was beyond normal and that it was striking in such a way as to start fires on the ground. It could also mean that fire went along the ground from the pounding hail.