Southern New England’s brief spring break this week will end with downpours, flooding, and a sudden return to the icy grip of winter Saturday as temperatures fall from the 50s to below freezing in about three hours, forecasters said.
The National Weather Service says heavy rainfall, potential flooding, and gusty winds Friday night will be followed by a “sharp turn to much colder weather” Saturday.
That will bring the rain to an end as freezing rain and sleet, but more importantly a flash freeze is expected, forecasters said in an Internet post.
Temperatures were mild Friday night, with temperatures holding near 60 degrees along the coast. Rain is expected to be heavy, with a risk of some thunderstorms.
“Rapid snowmelt combined with the heavy rainfall will result in a significant urban street flooding threat through tonight. This will be exacerbated around any snow-clogged storm drains. Some minor river and stream flooding is also possible and we can not rule out isolated ice jam flooding,” the forecasters said.
Flood warnings were in effect Friday night through early Saturday morning for the entire state except the Cape and Islands, and the warning was extended for eastern Massachusetts and Rhode Island through 7 a.m. on Saturday. The weather service said public safety officials were reporting multiple instances of small stream flooding.
Winds were expected to gust up to 50 miles per hour Friday night across portions of Eastern Massachusetts, peaking from midnight to near daybreak, the forecasters said.
A cold front will move into the state from west to east, approaching the I-95 corridor before dawn. Temperatures will rapidly fall below freezing.
“Our forecast has the flash freeze occurring during the morning in the interior and late morning into early afternoon in the coastal plain,” forecasters said. By late afternoon, the temperatures are expected to be in the teens and 20s.
Dry but cold weather is expected Sunday and Monday. There’s a chance of snow Tuesday and Wednesday. Dry weather is expected Thursday and Friday, but forecasters are watching a potential coastal storm that could hit Thursday.
Forecasters warned of dense fog and strong wind gusts that could bring down power lines, in areas of Southeastern Massachusetts and the Cape and Islands.
As of 9:45 p.m., nearly 3,900 business and residential customers had lost power, according to the Massachusetts Emergency Management Agency. More than half of those outages were in Cohasset, where police said a transformer on Route 3A exploded.
MEMA urged residents to clear snow and ice from catch basins and storm drains in their neighborhoods, avoid parking in flood-prone areas, and move things stored in basements to higher spots in the house to reduce the effects.Felicia Gans of the Globe Staff and Globe Correspondent Jacob Carozza contributed to this report. John R. Ellement can be reached at firstname.lastname@example.org. Follow him on Twitter @JREbosglobe.