Showers Likely Saturday

THU 5/29: A great second half of the work week will give way to clouds and showers on Saturday, with heavier downpours and embedded thunder possible. Hopefully things will move out in time to salvage a nicer day on Sunday.

Before the wet weather arrives Saturday, we will get the opportunity to enjoy another nice day on Friday. Conditions will be quite similar to those seen on Thursday with highs in the 65 to 70F range and plenty of sunshine. It may be a touch cooler on parts of the Outer Cape and a few clouds will move in during the afternoon, but overall a nice end to the week is expected. Temperatures will average out around normal and Friday will mark the 3rd straight day with sunshine and lots of blue sky.

Unfortunately, just in time for the weekend, things look to turn unsettled - at least for Saturday. A low pressure system will move in from the west, heading from the Great Lakes into Southern Canada, first dragging a warm front across the region Friday night, and then sending a cold front through the area later Saturday afternoon or evening. With the warm front passing to our north, winds will turn to the southwest and moist air will build into the region as a strong low level jet stream moves overhead. Dew points will surge toward 60F by Saturday afternoon, making for a rather muggy day - especially if we can break out into in some sunshine at times. Add to the mix some energy progressing eastward in the jet stream, the eventual forcing of the surface cold front, and the makings will be there for a couple of rounds of showers and thunderstorms.

Computer guidance is fairly consistent in delivering 1/2 to 1 inch of rainfall as some heavier downpours push across the region thanks to the warm, humid air in place. What remains to be seen is exactly how this wet weather times out. It's possible that we get an early round of showers and thunder as the warm front and its associated instability moves through, see some drying and even some breaks of sunshine while we are in the warm sector during midday on Saturday, only to see a more solid line of showers and thunder later in the day. This overall weather set-up is a bit more favorable for thunder on Cape Cod than what we saw earlier this week.

One thing is for sure, it will be muggy and quite breezy. South to southwest wind gusts past 35 mph are likely throughout the day. There is one other thing to watch: with dew points climbing, low clouds and fog may develop south of the Cape and spread across the region Friday night. This deck of gray might be hard to shake during on Saturday across parts of the Cape - especially out near Chatham, along parts of Buzzards Bay and the shore of Nantucket Sound - perhaps spoiling any midday sunshine that might try and break through.

Earlier in the week it appeared as though Sunday might be in jeopardy as well, however, as the weekend has drawn closer, confidence is growing that this weather system will remain just progressive enough for drier air to move in for the second half of the weekend as winds flip to the northwest. Sunshine should return and temperatures should top out near 70F.