A day north of the warm front

Today was a unique weather day here in Annapolis. The broad synoptic-scale setup featured a deep closed low circulation over the Ohio River valley with a warm front extending east to the Atlantic coast. Despite not being predicted by most of the short-range numerical models, I expected the warm front would lift north of us today (considering it started the day paralleling the Potomac River). However, the front never made it as far north as I expected ... although it got really close to us! Andrews Air Force Base, about 20 miles to our west-southwest, warmed into the mid-70s; we briefly hit 63F before falling back into the 50s with drizzle and mist (see figure below). I said "unique" to start this paragraph because I'm not sure I've ever been this close to a warm front and not have it pass through, plus a 15-degree horizontal temperature gradient over 20 miles is pretty impressive!


The warm sector to our south is characterized by instability (CAPE > 1500 j/kg) and some wind shear, and as the deep closed low translated toward us, the SPC issued a Severe Thunderstorm Watch. One storm over the Blue Ridge in eastern West Virginia even exhibited brief low-level rotation, prompting my friend MK at KLWX to issue a Tornado Warning. No reports of tornadoes were received, though, and by 00Z the only severe reports in the Sterling CWA were for hail. We'll see what happens as the cluster of storms currently entering western MD move east during the evening and overnight.