Cold weather possibilities: Will it really snow?
SAN ANTONIO -- Wednesday was been a cold and rainy day, and up in the Hill Country there's the possibility of snow or rain, or both!
It is definitely a challenge this time of year with the change in elevation from S.A. to the Hill Country and the fact that it's hard for really cold air to make it this far south for long. There are some basic weather scenarios that might help explain these kinds of situations:
There are several potential weather scenarios we can face:
Scenario One: Clouds in the atmosphere above us produce precipitation. it's going to be snow because it's cold up there. The snow falls through some warm air and the snow melts and becomes rain like what we had all day Wednesay.
Scenario Two: Snow falls, melts in the warm air above us and becomes rain. But the temps on the ground are freezing so it freezes on contact and we have freezing.
Scenario Three: The next scenario gets a little trickier. When the warm air above us is not very thick then it will start to melt the snow as it falls through it but still has time to re-freeze before it hits the ground. We usually call this sleet.
Scenario Four: The air above is cold enough, so it doesn't melt all the way down, and it stays snow when it hits the ground.
Now here's another twist. Let’s add some hills, like our Hill Country, 1500 to 2000 feet higher than San Antonio. When you add the hills, there are places where the snowflakes won't have enough time to melt but the air around them is above freezing, so we get a mix of rain and snow.