This is called a cut-off low. One of the key characteristics of a cut-off low is that it moves very very slowly causing persistant rains and storm development. Another reason it has hardly budged is that the systems east of it hardly moved. When we look at a weather pattern in a local area, we have to take into consideration all other patterns as these may have an influence. Think of it like a traffic pattern. The globe contantly attempts to balance warm and cold air masses. At this time of the year, when cold air masses sink into the lower latitudes, the globe tries harder. Hence, these lows are not so unusual. This has nothing to do with HAARP.