Moderate Snow Threat Tomorrow

by | Jan 6, 2017 | Public

A chance of snow has sprung up across the region tomorrow as the precipitation shield of a rapidly strengthening low pressure center will expand further west than previously expected.  Premium subscribers received a detailed update earlier in the day and will receive coverage of the storm through the next 24 hours, while below we have listed our latest forecast:

Light to moderate snow breaks out between 9 and 11 AM across the region tomorrow morning.  It will start light, but begin to pick up in intensity between 12 PM and remain steady and moderate through around 7 PM.  Intensity will generally be light but some moderate pockets of snow will be possible as it does remain relatively steady.  Between 8 and 11 PM snow should wind down across the region, ending entirely overnight tomorrow night.

A rather sharp snowfall gradient is expected across the region, which is keeping confidence below average for this snowfall event tomorrow.  Models have shifted rather dramatically in the past 24 hours ahead of this storm, and with such short-term volatility we can expect some surprises to continue into the day tomorrow.  Short-term guidance is some of the most aggressive, showing that eastern areas could see up to 6-8 inches of snow, while global models show amounts closer to 3 or 4 inches.  One of the more complex variables is how cold it will be and thus how light and fluffy the snow will be again.  Snow to liquid ratios up to 20:1 may again be possible with the storm moving through, so even though liquid amounts will be less than half an inch we could still have moderate accumulations.  Later in the storm winds will pick up a bit so we could see some dendrite shattering (depending on exact snow growth regions) that may bring ratios down a bit, but at least 15:1 ratios seem reasonable.

Accordingly, I see the potential for 4-7 inches of snow to fall across New Haven County.  2-5 inches of snow is likely across Fairfield County, with 1-3 inches of snow expected across Westchester County.  However, the gradient may be a bit more sharp, meaning we could go from 6-7+ inches of snow in southeastern New Haven County down to just 1 or 2 inches in inland Westchester County.  A model consensus shows around 4-5 inches of snow across coastal Fairfield County with 3 inches or so expected most inland areas.  This all is based off of the latest guidance out over the past 2 hours, though again a shift of 20 miles either way could bump up or drastically reduce accumulations through the day tomorrow, and models remain in a bit of flux playing catch-up with this storm so if this trend west remains sustained I may need to upgrade Fairfield and Westchester County accumulation forecasts slightly.

Models Back Off Snowfall Expectations Overnight

by | Jan 5, 2017 | Public

Our forecast for light snow has been updated.  The updated forecast is available below, having just been emailed out to Premium members.  To view the updated school delay chances, subscribe here.  Otherwise, the latest forecast is below:

Light snow showers begin to move in across the region over the next couple of hours.  Steadiest snow is then expected between 1 and 5 AM, moving from west to east.  Between 5 and 8 AM we rapidly clear out, with the entire region dry by 8 AM as the sun attempts to come out by late morning.  Only an hour or two of steady snow is really expected in any one location as the storm remains very unorganized.

Current snowfall estimates have been updated to a coating-2 inches regionwide.  No longer does it look like much more steady precipitation will occur at the coast, and most models backed off the more impressive liquid amounts they had been showing this morning.  Interestingly, the National Weather Service updated the coast to a Winter Weather Advisory this afternoon which was in line with our previous forecast, but recent updates indicate that this may be overdoing it as I would be surprised for anywhere to see more than 2 inches.  Amounts closest to two inches are likely across coastal New Haven County, with generally an inch or a bit less expected across Fairfield/coastal Westchester County and even less expected across inland Westchester County.  No longer is an inch a guarantee even in coastal areas as steady precipitation looks to have shifted just a bit south, lessening impacts.

Minimal travel impacts tomorrow morning are likely for the Friday morning commute.  Of course, snow will be light, so impacts will be minimal, but slippery travel looks most likely between 3 and 6 AM.  Snow will stick instantly on roadways with cold temperatures, and though it may not be too icy and snow will not be heavy it may be hard for any sand/salt to melt much of the snow, so we could see slushy/snow-covered roads into around 7 AM.  Temperatures struggle to rise above freezing, so some snow could linger on back roads later into the morning.  Accordingly, just be slow to take it slow tomorrow morning, especially if you are out before 6-7 AM, though with only an inch or so of this light snow it is unlikely to have too much of an impact.