Good morning all! As previously advertised in yesterday’s weekly outlook, there is the threat of a wintry mix for the region Thursday morning.  As the first of two significant moisture plumes lifts north out of the southeast, the moisture will ride over the top of a colder air mass and produce a mix of snow, sleet, ice and rain.

Thursday 4 am Temperatures – WeatherBell, LLC

Early Thursday morning temperatures across the region are cold enough to support snow everywhere initially. However, warm air will quickly move in aloft melting the snowflakes and switching the snow over to sleet & freezing rain.

Thursday 925 mb Temperatures 4a->7p – WeatherBell, LLC

Warm air quickly wins the battle aloft as shown by the loop above where above freezing temperatures quickly move northward during the day Thursday.

Thursday Surface Temperatures – WeatherBell, LLC

Because cold air is more dense (heavier) than warm air it is tougher to move which causes a lag between the temperatures aloft and at the surface. This lag is what causes the period of mixed precipitation. While temperatures aloft are well above freezing, temperatures at ground level are only a few degrees above. This is called an inversion. Typically temperatures decrease with height, but in this situation, temperatures will actually increase the higher one is. This inverted temperature profile causes the snowflakes to melt then refreeze as they fall through the atmosphere.

Overall, what this leads to is a period of snow, followed by a period of sleet & freezing rain which ends as either rain drops or more likely a prolonged mist Thursday afternoon.

Thursday 1a -> Friday 1a Precipitation Type – WeatherBell, LLC

Snowfall accumulations across the region should be minimal as the snowfall window is pretty small in most locations.  Here is what I am currently thinking:

Thursday Snowfall

-Chris


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