A Soaking Rainfall Is Expected Throughout All Of Wednesday & Into Wednesday Evening: A strong storm system and its associated frontal system is expected to affect the entire area throughout all of Wednesday and into Wednesday evening. This storm system will bring with it heavy rain which will lead to river, stream and urban flooding and windy conditions.
Heavy Rain With The Flood Threat: Some scattered showers can be expected to begin this evening and then continue throughout the overnight hours of tonight. It should be noted that some freezing rain showers could occur during this evening leading to some light icing issues as well as the potential for some slick conditions. Temperatures will rise well above freezing after midnight and because of this, the threat for freezing rain will end.
Steady rain is expected to begin across the entire area between 3 am and 5 am Wednesday morning.
The heavy rain threat is expected to occur in two parts:
The first round will occur during Wednesday morning with rain expected all morning long. Some of the rain will fall at a moderate rate at times.
A break in the steady rain looks to occur from about midday until about mid-afternoon. That said, there will still be scattered showers around during the early afternoon hours.
The second round is expected to occur beginning around 3-4 pm Wednesday afternoon and last until about midnight Wednesday night. A strong cold front is expected to push through the area during this time frame. Out ahead of this front, rain, heavy at times can be expected from late Wednesday afternoon right through all of Wednesday evening. Additionally, there is expected to be some unstable air around when the front moves through and because of this, a few embedded thunderstorms are possible between about 6 pm and 10-11 pm Wednesday evening.
Rain ends around midnight on Wednesday night.
Total rainfall amounts of 2 to 3 inches can be expected across the entire area. There is the possibility of isolated rainfall amounts of up to 4 inches.
This heavy rain will combine with a lot of snow melt from northern New England to lead to some of the big rivers across Western and Central Mass to reach near flood stage. More likely though, some of the smaller rivers, streams and brooks feeding off of the big rivers are more likely to go into flood stage with this heavy rain event.
Also, flooding of roads, highways, areas of poor drainage and urban areas is likely as the rain will be falling onto a partially frozen ground & because of this, the rain will run off rather than soak into the ground.
Windy To Very Windy Conditions Expected Wednesday Afternoon Into Wednesday Night: That strong cold front is also expected to bring with it the potential of windy to very windy conditions beginning on Wednesday afternoon and continuing into Wednesday night.
At this point, it appears that South winds of 20 to 30 mph with gusts to 40-50 mph can be expected throughout Wednesday afternoon and Wednesday evening. These wind gusts will need to be watched though during Wednesday evening as any embedded thunderstorms could pull down some 55-60 mph wind gusts.
The combination of the heavy rain and windy conditions will likely lead to the potential for some downed trees and some power outages.
Black Ice Threat: Temperatures are expected fall quickly behind that front from the low to middle 50s during Wednesday afternoon and Wednesday evening to the low to mid 30s shortly after midnight Wednesday night.
Because of this, there is likelihood of icy conditions to develop during the after midnight hours as all of the moisture from the heavy rain freezes up.
This means that you need to be aware that any remaining water or moisture on roads, parking lots, driveways, stairs and decks are likely to freeze up from just after midnight Wednesday night right through the Thursday morning commute.