By Terry Eliasen, Meteorologist, WBZ-TV Exec. Weather Producer


BOSTON (CBS) – Searching for signs of spring?

We finally have some good news from the weather department.

In the next three days we will lose more than 50-percent of our snow pack. A good 6-to-8 inches of snow will be erased from our sidewalks and backyards by this weekend!

It will be our most significant period of snow melt thus far, likely revealing parts of our landscape not seen for months. If you are like me, you probably have lost a few gloves or perhaps a shovel or two to the immense snow piles in your backyard and around your driveway. Who knows what might be uncovered in the coming days? A missing or broken gutter? Your favorite garden gnome? Perhaps a dog bone or two? It will be like Christmas in March, a veritable treasure trove of missing items and junk are about to be revealed.

So why the sudden end to our mini ice age?

Well, there is the obvious and overriding factor of the changing seasons and the strengthening sun. But, over the next few days, several atmospheric ingredients will combine to create the perfect recipe for massive snow melt.

(WBZ-TV graphic)

(WBZ-TV graphic)

Mild Temperatures:

Did you know that high temperatures this time of year are supposed to be near 50 degrees? I only ask the question because we have spent so long below average in the last few months we may have forgotten what “normal” feels like.

Well, we are in for a solid three days of near to slightly above normal temperatures! What a novel concept! Temperatures will peak in the 50’s during the day on Thursday, likely falling just shy of the magical 60-degree mark.

Can you recall the last time we hit 60? We nearly did it on Christmas day, when temperatures peaked at 59. But you have to go all the way back to December 1, 2014 for our last official 60 in Boston – 114 days ago.

Even more important than the high temperatures in the next few days will be the amount of time we spend above freezing. We went above 32 degrees at 8 a.m. Wednesday morning, just the beginning of a 60-to-70 hour stretch above the freezing mark (until early Saturday).

(WBZ-TV graphic)

(WBZ-TV graphic)

(WBZ-TV graphic)

(WBZ-TV graphic)

High Dew Points:

One the most important and perhaps overlooked factors in melting snow is the dew point. When you add humidity to the air, condensation begins to occur and this releases heat to the rock solid, frozen snow pack. There is currently about 2-to-5 inches of water still locked within the snow and dew points in the 40’s and 50’s over the next few days will aid in releasing a good deal of that water.

(WBZ-TV graphic)

(WBZ-TV graphic)

 

(WBZ-TV graphic)

(WBZ-TV graphic)

Rain and Flooding:

Believe it or not, rain is not really that big of a factor in melting snow.

In fact, a cold rain can actually make things worse and literally just be absorbed by the snow, adding to the amount of water with the deep pack. It appears as though most of southern New England will see between 0.5 and 1 inch of rain between Wednesday night and early Friday. Combine that with the rapid snow melt, and we could see 2-to-3 inches of water funneling into local rivers and streams. Likely not enough for any major flooding concerns, but some minor urban flooding does seem likely.

This would be an excellent time to check the storm drain and be sure that it is not blocked or clogged.

By my estimation, it appears as though we have avoided what could have been a massive spring flooding issue.

Just a few weeks ago we had record levels of snow blanketing the entire region. Most rivers were iced over, and the potential was there for massive ice dams and historic spring flooding.

At one point we had nearly 10 inches of water locked within our snow cover. Had all of that been released at once by a week of warmth and rain storms, the damage could have been catastrophic.

The higher sun angle and chillier than normal daytime temperatures this month have allowed for a very slow and orderly melting process thus far.

We have already lost at least half of our snow pack from a few weeks ago and, therefore, avoided a worst case scenario. Rivers will continue to rise over the coming weeks as they always do this time of year, but if we can avoid any massive rainstorms and additional significant snow accumulations, I think we might just make it through “mud season” relative easily.

Follow Terry on Twitter @TerryWBZ

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