A Snowy Tuesday NightJanuary 28th, 2014 at 10:09 pm by Tiffany Savona WAVY under Weather
Snow has been falling for the past couple of hours now and most locations have anywhere between 1-3 inches of snow on the ground so far. The snow is a very fine granular snow, which is common with dry snow. Meteorologist Don Slater and I have been watching this evolving snow storm and have come to a few conclusions about this event. First of all, the snow started a few hours later than the models predicted. This was due to the dry air in the lower levels of the atmosphere. We call this phenomenon virga. Virga is precipitation that falls, but evaporates before hitting the ground. If you watched us on WAVY News 10 at 4, 5, 6, you would have noticed that Super Doppler 10 radar was covered in blue. But most of the snow was not reaching the ground or just falling as flurries. This is what the radar looked like 4:20 PM earlier this afternoon. There were pockets of snow reaching the ground, but most of it was evaporating since dew points were in the single digits.
Once we moistened up the atmosphere, the snow began to fall, heavy at times. During the newscast, we were talking about the possibility of snow mixing in with sleet across Northeast North Carolina. This sleet would cut down on snow totals, but it would also make the roads more dangerous. Why would we see sleet with temperatures in the 20s? Well we are seeing warmer air a few thousand feet above the ground. This warmer air is located out ahead of a lower level front (850 mb front). Yes, we can have fronts, or temperature gradients throughout different layers in the atmosphere. Just like down at the surface, these fronts can create bands of heavier precipitation. That is one reason why the snow should get heavier overnight. Before this 850 mb front moves in, there is a chance to see sleet, mainly across North Carolina. The sleet will starts out as snow. Then the snow melts when it falls into the thin warm layer aloft. There is a very cold layer of air right near the surface, which is why we are seeing temperatures in the teens and 20s. The melted snowflakes then re-freeze back into ice pellets or sleet. Sleet can be more dangerous on roads, since it will create a layer of ice.
Snow to liquid ratios are often used to determine how much snow will fall. On average 1 inch of liquid will equal 10 inches of snow. If the snow is wet, then we will see lower ratios or less snow. Drier snow will typically yield higher ratios. So far, we have seen about 0.1 of an inch of liquid and we have about 3 inches on the ground. Many computer models show about 0.75 to 1 inch of liquid precipitation, but the computer models have been overdoing it big time so far. So Don and I have taken down the snow totals just a little bit. Here is our latest snowfall totals map that we put together.
*Notice that we are still expecting significant snow across the region*
WAVY has already received hundreds of snow photos. Our web producers have been working hard to put them all in a slideshow for you to view. Remember you can always send photos to firstname.lastname@example.org. You can also post them on our Facebook page or Tweet them to us. Just use #superdopper10. If you want to know how to measure snow correctly, read the blog we posted earlier. Thanks again for all of your photos and reports, they really help us out!
Meteorologist Don Slater and I will have an updated list of snow totals plus photos to show on WAVY News 10 at 11. Meteorologists Jeremy Wheeler and Jeff Edmondson will be in early tomorrow morning with an update on weather and road conditions on a special edition of WAVY News 10 Today starting at 4 AM.
-Meteorologist Tiffany Savona