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Weekend Storm Could Bring Flooding Followed By Flash Freeze To Boston Area

BOSTON (CBS) -- What a difference a week makes.

Last week at this time the buzzwords were record cold, blizzard and bombogenesis. Now, just a week later, we are talking about near record warmth, heavy rain and flooding. We're off to a raucous start in 2018; what could be next?

Not to belabor the point, but the contrast from last week to this one truly is amazing.

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Last week we never got above the freezing mark in Boston, averaging a daily high of just over 20 degrees and a daily low in the single digits. This week, we will be above freezing every single day, including a couple days 50+!

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Our average daytime high by the end of this week will be somewhere in the 40s and the average low likely 30+. While many of you may be happy to thaw out, the sudden change in weather is sure to cause more headaches.

Let's break it down. . .

Thursday:

Lots of clouds around but temperatures will nick 50 degrees in many towns in eastern Mass. It would be the first 50 in Boston since Dec. 19. Lots of melting, nothing hazardous just yet. A good day to clear the storm drains and check the sump pump in the basement.

Friday:

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A rainy day, with about .5" to 1.5" between 7 a.m. and 7 p.m. If this were the end of the rain story, it really wouldn't be a big deal. Some very big puddles, some pockets of street flooding, but nothing overly impactful just yet. Temperatures on Friday should easily reach the mid 50s, undoubtedly breaking a few records in the Northeast. Boston and Worcester will likely NOT see any high temperature records (Boston: 62 in 1975, Worcester: 57 in 2017).

Friday Night:

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The rain starts to intensify Friday night into Saturday morning. The heaviest rain will likely be located across eastern and southeastern Mass., including some very heavy downpours and perhaps a few rumbles of thunder. Combine the heavy rain with overnight temperatures still in the 50s and some significant street/urban flooding is inevitable. Rainfall totals in parts of the area (east/southeast) could range between 2-4"+ by Saturday morning.

Saturday:

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As the rain continues to pour down Saturday morning, a temperature crash will be arriving from west to east. Around dawn on Saturday we will have temperatures near 60 over parts of southeast Mass. and in the 20s in western Mass. That cold air will quickly spread eastward Saturday morning, changing the rain over to a mix of ice and snow. Good news is that the precipitation will be coming to an end by midday Saturday so there shouldn't be much chance for any significant ice or snow accumulation.

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The main concern during the day on Saturday is for a flash freeze. Any standing water (and there will be a lot of it) will freeze up quickly. Temperatures will go below 32 degrees north and west of Boston during the mid-morning, in Boston by midday, and south of Boston in the afternoon.

Wind:

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During Friday and Friday night the winds will get fairly gusty out of the southwest. In fact, gusts as high as 45 mph are possible over the entire region, and a few gusts to 50+ could occur in higher elevated areas. By Saturday the wind will have quieted inland, but over southeastern Mass. and the Cape some strong southerly gusts (as high as 60 mph) are likely.

What's next?

The cold that arrives on Saturday will stick around a while (again). While not nearly as harsh as our last cold outbreak, we are likely in for another stretch of several days below freezing (Sunday into next week). So any ice left on your driveway from the flash freeze won't be melting anytime soon.

As always, stick with WBZ-TV and CBSBoston.com for frequent and important updates!

Follow Terry on Twitter @TerryWBZ

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