Where is the snow?

As a forecaster, the goal is to get the meteorology right (storm track, thermal profile, dynamics) when a storm is approaching. Once the meteorology is correct, it is fairly easy to predict the weather (temperatures and precipitation) and you will generally be correct 99% of the time.

When you get the meteorology exactly right but incorrectly predict the weather, all you can do is shrug your shoulders and chuckle.

At 10:00 pm Wednesday night, the NWS issued a snow advisory for south-central KY with a forecast of 1-2 inches of snow by midday Thursday, WNKY and WBKO had a forecast of 2 inches, and of course, yours truly was predicting 1-2 inches as well. Some national meteorologists were predicting 3-6″ for the area right on the KY-TN border. All of these forecasters got the meteorology right. A surface low did track across the Gulf coast states, the air was indeed cold enough to support snow, and the dynamics were available to provide lifting. So why didn’t it snow?

This radar shows why. There was a small pocket of dry air aloft located directly over central KY as the storm approached. This is why the snow shield appears to split right around KY as it approached our area. This was not picked up by any models since it was located between the nearest upper air stations (Nashville and Indianapolis). Since the models didn’t know the dry air was there (and neither did the forecasters), there was no way to know that the moisture to the storm would evaporate before snow-producing clouds could develop. The most snow that occurred in south-central KY was only a light dusting. Only now, as the pocket of dry air has moved over Nashville, have the models figured things out (a little after the fact, of course). Note that the 06Z computer models (which comes out after midnight, a little too late to be useful) shows the dry pocket over south-central KY. Note the difference from the 0Z forecast (from 6:00 pm Wednesday) which shows the green over our area and predicts the snow.

The only good that may come from this busted snowfall forecast is that now the atmosphere is not as dry, which means that the second storm, which will move to our south this evening into tonight, (currently over the Ark-La-Tex) may actually bring us that long-awaited inch of snow.

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