Gas prices are continuing to trend upward heading into the Memorial Day travel period.

Even with those trends, Kansas and Oklahoma are still among the cheaper states in the country right now. AAA reports the Kansas average is sitting around $3.99 a gallon, up roughly 35 cents from a week ago and Oklahoma is sitting at around $3.89 a gallon up 25 cents from a week ago. Nationally, prices have climbed even faster, with the average now above $4.50 a gallon. Analysts say global oil supply concerns tied to tensions in the Middle East are driving much of the increase. GasBuddy analysts are warning Kansas could average around $4 a gallon statewide by Memorial Day if oil market instability continues.

For southeast Kansas and northeast Oklahoma, that likely means drivers will notice prices continuing to inch upward over the next couple of weeks, especially along heavier travel corridors and near highways. Even so, Oklahoma and Kansas remain among the least expensive fuel markets in the nation.