Mostly Cloudy, Chilly; Slight Chance of Sleet Before Sunrise

Temperatures have fluctuated between the upper 20s and 30 for much of the night as an extensive cirrus shield blanketed the area. These clouds will stick around for much of the day as a tropically connected branch of the subtropical jet remains entrenched across the region. The confluence of the subtropical jet and the polar jet will take place to our north, which will place the Deep South in the right entrance region of the jets. The vertical motion associated with this quadrant will help initiate a surface low pressure in the western Gulf of Mexico this afternoon. The low should contribute to a gradual increase in moisture over the course of the day. However, rain chances will be kept at bay as a strong surface high remains in control of our weather. Since skies will be mostly cloudy today, highs will remain on the chilly side as we should only top out near 43.

By this evening, cloud cover will thicken and lower as moisture increases due to the surface low in the Gulf and as isentropic processes commence. I'm always leery of model guidance that holds off the onset of the precipitation when moderate large scale ascent is occurring. If the models are indeed correct, we should remain dry through sunrise tomorrow morning. However, with the strong vertical lift, I feel that a slight chance of precipitation is warranted just before sunrise. If precipitation does indeed occur before sunrise, the amount of dry air in the lowest 8,000 feet would support evaporative cooling. The evaporative cooling would produce a thermal profile supportive of a period of sleet. I don't expect any travel problems to occur as the precipitation will be very light. Lows tomorrow morning will be near 33.