Based off SPC meso analysis, it appears as though the 925mb temps have trended cooler over the past 2 to 3 hours. The 0° line is now draped along the Potomac River to US 50. The 850 0° seems to be between the I-270 and I-70 corridor and has kinda stalled out. Just a nudge further south of may 20 miles would be a big boom for a lot of folks tonight.