A badly-needed storm system packing lots of moisture has made its way into New England today and is expected to linger over the next day or two. The Boston area has been seeing light rain, which is expected to ramp up over the next 24 hours and dump a total of 1 to 2 inches through Saturday. As the low-pressure system swirls over New England, broken showers to periods of heavier rain will pull in from the south this afternoon and into the overnight with varying intensity.
After a brief drying period, a secondary system that has evolved off shore will bring another wave of rain into the region Friday afternoon. The rain, however, should remain light enough to avoid any flash flooding.
This wet weather will stick around through the first half of Saturday. New England hasn’t seen any significant rainfall since September, and it’s hoped that this system can help relieve the months-long, sweeping drought that has gripped the Northeast.
Timing
The rain will vary in intensity throughout the day, with breaks in between pockets of light and heavier rain. Relatively warmer air will surge into the region from the south and keep fueling showers and steady rain across the area.
Southern New England
• 3 - 7 p.m. — Rain becomes heavier and more intense. Broken showers to periods of steady, heavy rain will continue to progress into the Boston area this afternoon. The increase in rainfall could last into the commute home, but as long as you’re taking it slow on the roads, it shouldn’t be too impactful.
• Evening/overnight — Lighter rain lingers tonight and overnight before tapering off before sunrise with the system pulling to the northwest, giving the region a break in precipitation. Higher elevations in the Berkshires will see a shift to a wintry mix and then snow overnight.
• Friday — After a break in the morning on Friday, scattered showers will begin to work back into the region around midday with more widespread rain returning from 2 to 7 p.m., with brief heavier downpours mixed in. Light showers should stick around Friday night with a bit more steadier rain Saturday morning before the storm exits.
Northern New England
• This afternoon and evening — Bands of showers and light rain will push into the northern tier Thursday afternoon with steady to heavier rain traversing through New Hampshire and Vermont between 4 p.m. and 10 p.m. Maine may not see heavier rain outside of showers until after 10 p.m.
• Overnight — Higher elevations will see a shift to a wintry mix and then snow overnight tonight as cold air filters south behind the system and temperatures dip near to below freezing.
• Friday — Scattered showers and mountain light snow will persist between 2 a.m. and 6 a.m. before a break in the wet weather arrives. Some heavy showers will be working through central and northern Maine during that time. Most of Friday will be spent fairly dry with scattered showers. Heavier rain returns between 6 p.m. and sunrise Saturday with spurts of steady rain or now in the higher terrains.
• Saturday — By morning, New Hampshire and Vermont see precipitation wind down with Maine dealing with steady rain until early to mid-afternoon.
Rain and snow totals
It’s looking like there will be plenty of moisture feeding this storm from the Atlantic, which has boosted the expected rain totals a bit to 1 to 2 inches through Saturday, with a few local areas seeing over 2 inches. There’s a decent chance that Boston could see nearly an inch of rain just from today, which would be the highest daily total for the city since Sept. 21, when nearly an inch of rain (0.90) fell. The higher elevations will see 1 to 4 inches of snow.
Here are the expected rainfall and snowfall totals through Saturday:
The snow will really be concentrated on the western side of the storm with several inches of snow possible across the mountains on Friday and Saturday.
Will flooding be an issue?
The answer is no. The rain will give New England a good soaking but there won’t be any flooding problems mainly because the ground has been so dry and is able to absorb this amount of rain. There may be a few shots of rain that can be heavy enough for some brief ponding of water but that should be about it in regard to the flood risk. The rain should remain light enough on Friday to avoid any flash flooding.
Cooler temperatures
Overcast skies and the rain weather will keep temperatures struggling to reach 50 degrees today. Most of New England will stall in the mid- to upper 40s as this system takes over.
How the storm will play out
Much of the area will stay mostly dry for the first half of Friday as the system pulls away slightly to the west.
Eventually, however, the low pressure will push back into the region and combine with another developing low offshore to reignite some showers across Southern New England Friday afternoon, and more widespread, heavier rain Friday evening and into Saturday morning.
It should reach the freezing mark in the higher elevations on Friday — especially across the White and Green Mountains, as well as the Berkshires, where snow should begin falling and start accumulating relatively quickly, leading to slick road conditions.
Saturday
Eventually the system will move out of the region Saturday morning, leaving behind a trail of scattered showers across Boston and Southern New England with heavier rain and snow showers lingering in Northern New England.
Heading into today, Boston and most of New England had been stuck in a persistent pattern of dry weather since mid-August that brought high pressure, thwarting storms as they neared the region. This, of course, has led to an expanded drought across New England and an unprecedented number of wildfires, particularly in Massachusetts and Rhode Island, to spread quickly amid the ultra dry and breezy conditions.
The US Drought Monitor on Thursday reported that Greater Boston and parts of Central Massachusetts — roughly 26 percent of the state — have now reached “extreme drought” conditions, the worst stage since last week.
This storm won’t be enough to pull us out of the drought, but it will certainly provide some relief for diminishing reservoir and groundwater levels as well as for the ongoing wildfires.
Thursday’s Breakdown
Southern New England: Pockets of light to heavy rain will progress into the region throughout the day under cloudy skies. There may be a few breaks during the day, but daily totals will range from 0.75 to 1.5 inches. It’ll be cool today by default with the wet weather. Highs may only reach the upper 40s. Wind speeds should stay relatively relaxed, below 10 miles per hour.
Western Mass.: Chilly day on tap with highs only reaching the upper 30s across the Berkshires and into the mid-40s in the Pioneer Valley. The rain begins before sunrise and should stick around for most of the day. Higher elevations in the Berkshires may see a switch to a wintry mix later tonight. Today’s rainfall totals may near an inch in this area of New England.
Cape and Islands: Rainy and cloudy throughout the day as temperatures stall in the low 50s. A breeze between 10 and 15 miles per hour is likely with rainfall totals around an inch.
Northern New England: With storm movement coming from the southwest, rain will progress into Vermont, New Hampshire, and Maine around mid-morning and will progress to the northeast throughout the day. Maine will likely stay dry the longest. Temperatures this afternoon should rise to the mid-40s, but temperatures slip closer to the freezing mark tonight, and a switch to snow is likely for the higher elevations.
Ken Mahan can be reached at ken.mahan@globe.com. Follow him on Instagram @kenmahantheweatherman.