Snow's coming, but it's a fine line

Update #431e

Hi again everyone 😊

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Now, to the forecast: snow is coming, but it’s a fine line. Let me explain…

The National Weather Service issued a Winter Storm Watch for the LOWER Hudson Valley (i.e. Putnam, Rockland, and Westchester County) for 6-9 inches of snow through Monday night. Orange, Dutchess, Ulster, and Sullivan County don’t currently have a watch (as of early Saturday morning).

This helps illustrate that the Hudson Valley looks like it will be near the northern fringe of the storm. Being on the fringe of a storm makes for quite a challenging forecast — a 20 mile shift north or south can literally make or break a forecast when you’re living life on the storm’s edge. Fortunately, we still have a good 48 hours for forecasting finessing.

Here’s what is known now:

  • Low pressure moves into the Ohio Valley on Sunday before transferring its energy to a coastal low on Monday. The coastal low will strengthen as a nor’easter.

  • A nor’easter on Monday will most likely gradually spread snow northward through the region. Whether that’s 6:00 am, noon, or 6:00 pm depends on how quickly snow moves northward (this should become clearer) and location. Southern areas (e.g. Rockland/Westchester will likely see snow earlier and northern areas (e.g. Ulster/Dutchess) will likely see snow later.

  • Right now, Monday night looks like the most likely time for the region to experience widespread snow.

  • The nor’easter will slowly move away on Tuesday, but backside snow could continue for a while. Beside the threat for more snow, cleanup will also be needed for previously fallen snow.

  • With the northern “fringe factor” at play, I’m still a little uncomfortable offering specific accumulation numbers. I’ll take a probabilistic approach for the time being: a high chance for more than 3 inches, a medium chance for more than 6 inches, and a low (but not zero!) chance for more than 12 inches.

If you’re wondering: what does this wacky forecast mean for school on Monday-Tuesday?

Well, as it stands right now, the uncertain arrival time of snow on Monday makes the call challenging, but with the fringe factor, it looks to me like a “better safe than sorry” situation — favoring closures.

With any cleanup needed as well as the potential for continued snow on Tuesday, it could end up being snow day #2.

While the puzzle pieces are coming together, we’re still missing two or three important ones that will help complete the picture. Until that happens, we’ll have to accept that the forecast and its impacts aren’t yet set in stone.

I hope to offer another puzzle piece or three tomorrow, so stay tuned! 😉

This is where I pondered the storm today…

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