October 2017 will certainly be remembered as a warm, sunny, dry and quiet month. We’ve gone 6 straight days, 9 of the last 10 days and 17 out of the last 20 days with above average temperatures. In fact, Hyannis has already recorded 10 days with temperatures over 70F in October (a “normal” October would see about 4) and is running nearly 6F above average thus far for the month.
At the same time, we’ve had little in the way of rainfall, plentiful sunshine and frequent days with very light winds. It’s been quite the stretch of weather.
Unfortunately, the jet stream is finally starting to shift around and a more active weather pattern is taking shape. Two potent weather systems will move through the area over the coming week – the first impacting the area today and tomorrow (and lingering into early Thursday) and the second moving into the Northeast and New England on Sunday and Monday.
As for the initial storm: formidable low pressure lifting through the Great Lakes is dragging a frontal boundary toward the Eastern Seaboard today. This storm center, propelled along by a strong upper air trough pivoting through the Ohio Valley, is producing a deep southerly flow of moisture up the East Coast. This southerly wind is transporting anomalously warm and moisture-rich air northward into our region and that air will fuel numerous showers, downpours and thunderstorms over the Northeast and New England…starting over the interior today and gradually seeping eastward over the next 36 hours.
Model guidance continues to show multiple rounds of wet weather passing over the area through Thursday morning, with embedded elements of heavy rain training from south to north over the Cape as we get into Wednesday and Wednesday night. Rainfall projections from multiple forecast tools suggest 1 to 2 inches of rain is certainly attainable region-wide and given the tropical feed of moisture…and likely tendency for downpours to “train” over some areas…it’s not out of the question that higher amounts are recorded in spots.