Another Round or Two...
As promised the muggy air would return and dewpoints have gone from the upper 50s yesterday to the upper 60s this afternoon. This along with an advancing frontal system has lead to tropical downpours and will lead to more.
A surface front guided by a well-defined mid level trough for this time of year are inducing soaking thunderstorms in Western New England and around New York City. The front will stall over us until tomorrow morning providing a conduit for low-level lift and moisture. The trough will continue to work overhead and a several vort maxes (spins in the atmosphere) will round the trough during the passage. Each vort max is the focal point for widespread shower and thunderstorm activity...pin-pointing their exact placement is the tough part...it can mean the difference between seeing street flooding rain or nothing at all. The first will slide just south of us this evening and radar supports that with an incredible thunderstorm complex south of Montauk, LI. The northern edge of this will spill into SE Mass through midnight producing some heavy rain. After midnight and tomorrow morning, another vort will slide through the rest of Eastern MA, especially the North Shore...this should trigger rain and downpours to develop early tomorrow morning. While I don't see an event like we had with the Wednesday morning commute and the flooding...some pockets of heavy rain could lead to more drainage issues. Following that the atmosphere will be gradually drying out through the rest of the day. Sunshine will make an appearance and the atmosphere will become marginally unstable again tomorrow afternoon for some pop-up thunderstorms despite the lowering humidity.
Friday still looks hot with 850mb temps supporting 90 degrees for many towns outside of SE Mass...a coldfrotn will approach for the evening and thunderstorms, some of which may be strong will spread in from the west near of after sunset. The front will stall like it's predecessors have the last couple of weeks leading to more soaking downpours on Saturday. I am cautiously optimistic at this point that most of Sunday will be dry and partial sun will prevail.
