wxman57 wrote:The one thing I'm not clear on as far as that Fort Worth AFD is the mention of freezing drizzle. All the vertical profiles I've seen indicate that once the surface temps drop to freezing that all the moisture above the surface will be in a sub-freezing layer. That means snow would be more likely than freezing drizzle, as freezing drizzle requires a warm layer aloft. There could be a brief period as the rain changes to snow that small warm pockets aloft could melt the snow on its way down, resulting in some light freezing rain. But such a changeover should occur quickly in the strong cold air advection behind the surface low.
remember that you are looking at a model sounding. typically model soundings underestimate the strength of the warm nose above the low level inversion. If this were the case, you would end up with a very shallow dome of subfreezing air, resulting in freezing rain/drizzle. keep in mind that the cold advection does not occur along a vertical line. the cold front slopes back over the cold air meaning that despite the cold advection at the surface, there is still typically warm advection above the frontal zone.