Brush With A Coastal Storm - Flakes Friday

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Many times we focus on the 'big' storms, but get lazy when the smaller events crop up. A couple inches of snow doesn't catch attention like a full fledged snowstorm, so we try to flag them as troublemakers even though they're no big deal in the greater scheme of winter. We saw this recently down in DC with the 1" of snow BEFORE the blizzard...which caused all sorts of chaos on the roads. Friday's snow locally has the potential to be in a similar vein.

On the forecast surface map, you can get a sense of that 'life line' between the ocean storm and the polar disturbance in the eastern Great Lakes. That trough acts as a focus for rising air, and for us that means areas of rain/snow. Source: Weatherbell

The main storm system will pass off to our east, bringing the heavy snow/wind/rain out to sea with it. But things get tricky here, as a strong northern stream (polar jet stream) disturbance swings in from the west. A 'life line' of sorts between the two will form, which we call a trough. A trough is basically an area of convergence, or where air is coming together along a similar line. When air comes together it has nowhere to go but up, producing clouds and precipitation. We had an event like this two weekends ago (Sunday evening into Monday). Snow totals weren't huge, mostly 2-4", but some were caught off guard because there's nothing to accompany the snow like the typical wind/storm headlines. No flashing warning signs for a larger impact.

So we'll need to keep a close eye on this trough late Thursday night into the first half of Friday. They're notoriously difficult to place, sometimes not nailed down until 18-24 hours in advance. It appears that areas of snow should break out after midnight Thursday in eastern Massachusetts, and may very well stick around into the midday hours on Friday. Toward the Cape and coastline, temperatures are very borderline and so rain may mix in, cutting down on impact and accumulations. Any snow that falls will be of the wet and heavy variety.

The takeaway is that everyone should be aware that bursts of snow will be possible during the Friday morning commute until lunch, slowing down travel and causing slick areas on the roads. I think at most we'd be talking about a localized total of around 3", with coatings to an inch more common than anything else. There's also an outside chance this trough sets up farther north toward coastal Maine, sparing us much of any impact. So stay updated on the weather and definitely check out the forecasts Thursday night/Friday morning to see if things are still on track. Any snowfall would likely wind down during the afternoon with a dry evening to lead us into the weekend.