DAYS 1-5 (JULY 16-20)
Today carries flood and severe weather potential from tropical showers and thunderstorms that will be moving mostly south to north while ribbons of them drift eastward in response to a slow-moving cold front and a saturated atmosphere. Torrential downpours and damaging wind gusts are the primary threats. Hail is a lower threat today. Lightning is a threat in any thunderstorm, though some produce more frequent cloud-to-ground lightning than others. The rule is, as soon as you hear it, the storm is close enough to endanger you, so move to a place of safety. Also never try crossing a flooded road, most especially moving water, in a vehicle or on foot. While many areas will come away with just a wet, muggy summer day, others will see the occurrence of the more severe weather from this event. Take note, be weather-aware, and don’t take unnecessary risks out there. Things settle down from west to east this evening and tonight as the front pulls through, and we’ll be set up for a much quieter day on Monday, with more sun, some clouds, and maybe a few pop up showers/downpours favoring southeastern MA / Cape Cod during the midday hours with some lingering tropical moisture being acted on by the July sun. Other than that, it will be mainly rain-free across the region, but quite warm and still humid. Another cold front approaches the region Tuesday. You might think “two cold fronts? why isn’t it getting colder?” … but keep in mind this is mid summer now and cold front is a relative term, especially in this pattern when you’re not tapping cool/dry air from Canada. These fronts are weak in terms of not delivering a cooler, drier air mass, but do provide a focus of convergence for shower/storm development. And we’ll see this chance again Tuesday afternoon and evening, but a little more progressively than today’s event. However, the threat of heavy downpours will be there and with the much of the region seeing heavy rain recently and again today, the flash flood threat will be renewed, just for a shorter period of time. This particular cold front will bring in slightly drier air for Wednesday, with will be a fair weather day from start to finish with no threat of showers/storms. We haven’t had many of those since the start of meteorological summer, but that day will be one of them. Humidity comes back up and at least the threat of a few isolated showers and thunderstorms Thursday as a weak disturbance moves into the region ahead of the next trough of low pressure that seem to occur in an endless parade this season.
TODAY: Mainly cloudy. Scattered showers and a few thunderstorms until midday then more widespread showers/thunderstorms from then on. Torrential rainfall and flash flooding likely in some areas. Damaging wind gusts and brief tornadoes may occur in isolated locations. Highs 72-79. Dew point 70+. Wind S 5-15 MPH but can be variable, strong, and gusty near any storms / downpours.
TONIGHT: Mostly cloudy evening with showers and a chance of thunderstorms. Breaking clouds overnight. Areas of fog. Lows 66-73. Dew point 65+. Wind S up to 10 MPH.
MONDAY: Partly sunny. Slight chance of a brief shower/downpour favoring southeastern MA midday. Highs 80-87, except cooler South Coast. Dew point 65+. Wind SW 5-15 MPH.
MONDAY NIGHT: Partly cloudy. Areas of fog. Lows 66-73. Dew point 65+. Wind SW under 10 MPH.
TUESDAY: Partly sunny. Showers and thunderstorms become likely from west to east mid afternoon to early evening. Highs 80-87, cooler South Coast. Dew point 65+. Wind SW 5-15 MPH.
TUESDAY NIGHT: Partly cloudy. Patchy fog. Lows 66-73. Dew point 60+. Wind W up to 10 MPH.
WEDNESDAY: Mostly sunny. Highs 80-87, coolest coast. Dew point near 60. Wind W up to 10 MPH but coastal sea breezes possible.
WEDNESDAY NIGHT: Mostly clear. A few fog patches in lower elevations. Lows 60-67. Dew point near 60. Wind W under 10 MPH.
THURSDAY: Partly sunny. Isolated afternoon showers and thunderstorms possible. Highs 78-85. Dew point rising to 65+. Wind S 5-15 MPH.
DAYS 6-10 (JULY 21-25)
A more limited chance of showers/storms but still there are a couple disturbances pass by on a more westerly flow. No major heat of the sustained variety.
DAYS 11-15 (JULY 26-30)
A similar pattern will continue late month – a few opportunities for showers/storms but a little less active overall, and no major sustained heat.