I've been lurking in this forum for a while now and finally have something to offer. I thought this as good a time as ever to join in. Here's a link that auto updates itself every time the National Weather Service (NOAA) comes out with its latest forecast. The area in this NOAA forecast is for Block Island Sound and surrounding waters.
http://weather.noaa.gov/cgi-bin/fmtbltn.pl?file=forecasts/marine/coastal/an/anz237.txt
As soon as I get to my other computer, I'll upload the link to the Narragansett Bay NOAA forecast.
If the winds are out of the South, I'd assume that the Sound forecast may be a better indicator of what you might expect. If the winds are from another direction, then the Bay forecast, , which is usually much calmer, might be relevant. Sometimes you'll see wording in the forecasts such as "expect higher seas at the Bay entrance".
Of course, when dealing with these forecasts, expect anything, iow, be prepared. Mariners out there may recognize that the links provided offer the exact script read by the computer generated voices on VHF NOAA weather radio.
btw, I agree with Diesel, knowing how fast these forecasts can change, it may still be too far out to predict the sea conditions...........
hth,
b