An approaching cold front will sweep through the cities this evening. A narrow band of showers and tstorms has developed ahead of the front, and is presently moving across the Appalachians. The line will move through the cities b/t 8-10 PM tonight. Expect showers, gusty winds and lightning.
High-resolution forecast models and radar trends suggest that this activity may be more of a threat north of the Mason Dixon Line. The strongest storms are located over central-southern PA, with isolated severe thunderstorm warnings there. The Storm Prediction Center expressed a 40% probability that a Severe Thunderstorm Watch would be needed this evening, encompassing PA and north-central MD, as far south as Baltimore, Howard and Carroll Counties. However, as of 5 pm, no watch has been issued. Conditions (instability, wind shear) are marginal for sustained or widespread severe tstorms.