Jan 6: Set the Alarms

Jonathan Carr
By January 6, 2020 16:46

Jan 6: Set the Alarms

Discussion: A very weak disturbance will form overnight tonight in the Tennessee Valley and track through the Delmarva Peninsula area by early Wednesday morning. This should deliver a period of rain-to-snow across parts of CNJ/SNJ between about 5pm and 10pm Tuesday night (tomorrow night).

There will be plenty of cold air aloft (at 500mb) with the trough overhead and even at the low-mid levels (700-850mb). The surface however (925mb down to the surface) is marginal for New Jersey meaning at or slightly-above freezing. In order for snow accumulations to stack up we would need to see very high rates of snowfall. It is possible but we’ve seen this story before many times. With the warmer surface temperatures leading up to the event (it will reach low-40s tomorrow during the day) there will likely be minimal road disruption from the snowfall. Temperatures should fall gradually during the precipitation but not fast enough for roads to get messed. You might see some natural surface accumulation but nothing significant.

I feel like 2-4 inches of snow are capable of falling from this light event but only a coating to an inch of accumulation is possible at most and likely only on natural/cold surfaces. I don’t see roads accumulating with snowfall. The biggest hazard is likely the mental state of mind of drivers Tuesday late-afternoon through evening while driving during snowfall. You know how everyone gets.

With all of this said I will quote the great Jonathan Wenner of Four Seasons Weather with “Set the alarms.” This will not be a school closing or even school delaying event. This will not cancel flights. It should simply be a conversational snowfall that MIGHT whiten up the trees, grass and parked cars that haven’t been running for a while.

In English: A rain to light snow event is likely between 5pm and 10pm on Tuesday (tomorrow). Currently SNJ especially SENJ is favored for the most wintry impact from the light system (which isn’t much). NNJ and even CNJ will likely be too far N to see such snowfall. Regardless of up to 2-4 inches of actual snow falling (in SNJ/SENJ) only a coating to an inch or so should stick to natural surfaces given the warmer surface after a day in the low-40s. Temperatures will likely not fall fast enough after sundown to warrant a concern for road accumulations. For good measure let’s allow a small wildcard in localized instances of snow falling hard enough to whiten some side streets. Not going to hold my breath for it though. Otherwise enjoy the conversational snowfall but set those alarms for Wednesday morning. Be safe! JC

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Jonathan Carr
By January 6, 2020 16:46