Metro Boston, North Shore and Metro West: The metro area and southern Middlesex and Essex Counties remained dry through the day and evening Thursday while explosive thunderstorms developed to our west and crossed the Route 495 corridor into the Merrimack Valley and then southeast New Hampshire and southern Maine late in the afternoon. Those storms caused locally damaging winds, hail, frequent lightning and flooding of streets and low lying areas where the torrential rains occurred.
Meanwhile, firework displays went mostly uninterrupted in the Boston area while organizers held their collective breathe with more showers and storms developing across eastern New York State and pushing eastward toward the Boston area. That activity arrived before midnight and brought another round of showers and storms.
Hurricane Arthur is now pulling away from the North Carolina Coast and moving northeastward at 23 mph. The forecast track brings him southeast of Nantucket later tonight and due east of Boston very early Saturday morning. The storm then moves across Nova Scotia Saturday. Tropical Storm Warnings are in effect from Provincetown to Woods Hole on Cape Cod and this includes Nantucket Island. A Hurricane Warning is in effect for the offshore waters south and east of this area.
Locally, we have a Flash Flood Watch in effect until 2 am Saturday morning. The National Weather Service is expecting the potential for 2 to 4 inches of rain from midday to just after midnight tonight.
A cold front is slowly moving west to east across southern New England this morning as the plume of moisture from Arthur pushes northward ahead of the front. As of 9 am this morning showers and thunderstorms are currently draped across western Massachusetts while the first of the outer bands from Arthur approach the south coast of New England. We should stay dry for most of the morning before the rain to our west and south converge on us this afternoon and tonight. Once that happens we can expect showers to be heavy at times with embedded thunderstorms possible. These heavier showers may cause local street flooding and flooding of low lying areas through midnight. Although still muggy today the temperatures will only stay in the mid to upper 70s. Light southwest to west winds.
Tonight, Arthur passes by to our southeast and east. He will be too far offshore to impact our area with gusty winds here on land but the offshore waters will get wind impacts from the passing hurricane. The rain is expected to continue into the early morning hours of Saturday. Temperatures fall into the 60s with winds turning west then northwest at 8 to 18 mph.
While Arthur invades the Canadian Maritimes Saturday high pressure begins to push into southern New England and will bring improving conditions for the weekend. Much less humidity, sunny skies and comfortable temperatures prevail. Highs near 80 Saturday to the mid 80s Sunday. Overnight lows from the upper 50s to mid 60s.
The ridge of high pressure controls our weather through Sunday and into Monday as the center moves offshore. This will bring us a return flow of south and southwest winds. Heat and humidity builds in once again early in the work week with a chance of showers on Tuesday. Highs well into the 80s Monday.