Heat advisories are in effect for much of inland southern and central New England Sunday. Temperatures near 90 degrees, along with high humidity, generate a heat index in the mid 90s.
Under a mix of sun and clouds Sunday afternoon we at least have a nice breeze from the southwest gusting to 25 miles per hour near the south coast. Humidity stays up overnight with the return of coastal fog and low temperatures mostly in the 70s.
There’s a slight chance for a shower or a thunderstorm Sunday afternoon and overnight. The most likely thunderstorm threat is far northern Maine.
The front generating those thunderstorms is going to slowly ease in from the north and west over the next several days. That will continue to draw air up from the south and west with temperatures a little bit warmer each of the next couple of days, more like the mid 90s for our Monday and Tuesday. The heat index will surpass 100 degrees at times during the afternoon. The threat for thunderstorms is still fairly small Monday, but the threat becomes greater starting Tuesday.
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The heat will gradually ease from north to south in the middle of the week. For central and southern New England we will likely top 90 degrees Wednesday and Thursday, making this a four- or five-day heat wave. But it’s also at that time that the thunderstorm threat really increases, with the potential for some damaging storms and also localized flash flooding, because there’s so much moisture in the atmosphere.
The early call for Independence Day weekend is not that great. It looks like a weather front stalls nearby with a threat for showers and thunderstorms continuing even though the temperature has cooled into the 70s, with more of a wind from the east Friday and Saturday.
Hopefully that outlook will be improving as we continue to monitor the changes in our First Alert 10 Day forecast.