Get ready to bring out the rain gear this evening! A strong cold front will slide through later today--bringing the potential for isolated strong to severe thunderstorms.
The Storm Prediction Center has placed the area under a Slight Risk (Level 2/5) as some of the short-lived storms could produce strong damaging winds, large hail, and even an isolated tornado or two.
There is a 2% risk of a tornado in place to the south of the city (green color) with a higher 5% risk of a tornado around the metro and to the northeast (brown color). This is may not sound very high, but the Storm Prediction Center does not issue a 5% risk of tornadoes often in the Mid-Atlantic region. This means that there is a 5% chance of seeing a tornado within 25 miles of a given point in the forecast area. The brown polygon shows the chance of a tornado is greater across NE Maryland, eastern Pa, NW New Jersey, and parts of Upstate New York.
The breaks in the clouds + elevated southerly winds + approaching cold front = plenty of instability aloft (greater CAPE values--Convective Available Potential Energy) There looks to be two round of showers and storms. The first round will be during the late-afternoon/early evening hours as pre-frontal showers and storms may pop up north and south of the metro. Some of these storms may produce large hail, damaging winds, and could rotate as shear will increase...keep a watchful eye to the sky when driving home from work.
The main line of showers and storms will enter central Maryland by 9 pm from west to east. Straight-line winds and an isolated tornado cannot be ruled out as the cold front makes its way through.
Showers and storms should clear out by Thursday morning with stubborn clouds holding on tight for the first half of the day. When its all said and done, rainfall totals could be anywhere from .25-1" on average with locally higher amounts possible if training takes place. This may be a problem for areas that are prone to flooding.