Over the last 2 months we have seen a rather persistent trough in the Eastern US with a persistent ridge in the west. This has at least prevented extreme heat (95-100 degrees or higher) from happening except for a couple of odd days here and there. Consecutive 90 degree or higher days have been limited to 3 days or so for most areas. At the moment the trough in the East is rather week which has allowed some hot humid weather to take over for a few days. Some troughing is going to flex its muscle a bit next week to bring some relief for a day or two. However the last 2 runs of the GFS and to some extent the European Model are showing signs that the trough may strengthen a bit. Of course we will need to see if this trend carries over through the next 4 or 5 days. Also we just had an upgrade of the GFS completed so let us see if the new upgrade improves the model. The last upgrade seemed to make it worse.
Im going to jump to next weekend after we get another warm front cold front combination late next week. This upper air would suggest a fairly decent push of cooler drier air into the Northeast & Middle Atlantic States. It would certainly continue the idea of short bursts of very warm to hot humid air for a day or two before a front pushes through.
The GFS model holds the upper air storm in Eastern Canada depicted above right through the first week...READ MORE AT http://www.meteorologistjoecioffi.com/index.php/2017/07/21/gfs-model-long-range-shows-deep-trough-east/