Check out the forecast sounding for central Alabama for this morning.
Notice the red line (temperature) and the green line (dew point temperature) are far apart from each other. That means the air is dry!
The blue line is the wet bulb temperature or the temperature a parcel of air would have if it were cooled to saturation by evaporation of water into it.
You'll notice that the majority of the blue line is below freezing.
Evaporative cooling we experience when we step out of the shower and feel a chill. Water is evaporating off our body which creates a cooling effect. The same thing happened in the atmosphere this morning.
The model showed precipitation arriving in Alabama later than when it actually did.
Here is a look at the simulated radar data for 6am this morning:
Now here is a look at the actual radar from 6am:
You can clearly see that the precipitation arrived ahead of schedule in the dry and cool air mass. So instead of it warming up and moistening up a bit more before the precipitation arrived which would have resulted in mostly rain, the rain arrived sooner and the atmosphere cooled enough for frozen precipitation to fall.
Well that's your meteorological lesson for the day ;)~~~
Have a good one,
Jill Gilardi WBRC First Alert Certified Meteorologist