7:00 pm UPDATE………
The threat of stormy weather remains. Until the final cold front goes through the area sometime after midnight, heavy rain and possibly a severe thunderstorm are possible.
The National Weather Service has outlined areas for the potential for tornado producing thunderstorms. A TORNADO WATCH remains in effect for the area outlined in yellow on the National Weather Service map below until 2:00 AM Thursday.
A FLASH FLOOD WARNING is also in effect for the western edge of the Tornado Watch area (red highlighted area). Some areas west of Baltimore have already received up to an inch of rain as estimated by radar up to 7:00pm.
4:15 pm UPDATE……….
The approaching squall line “deflated” in a manner of speaking as it approached the metro area. The line of rain became more diffused and produced a period of moderate shower activity generating a quarter to half inch rainfall in one hour as estimated by National Weather Service radar. Parts of northern Virginia received up to one inch of rain before the squall line weakened. See the image below.
The rainfall will continue across the area past sunset with the leading edge moving to the east and southeast.
A squall line is approaching the Baltimore metro area as of 3:15pm. Strong gusts and briefly heavy rain likely with passage. On the surface analysis below, note the temperature fall on the station reports to the west. Click on the image to enlarge it for detail.
It happens, but not that often. At midday, temperatures around Baltimore are in the upper 60s. Readings are running 10-15 degrees cooler near the Bay with wind coming off the cold water temperatures.
Wednesday’s record high is 72 (1914) and by noon the BWI temperature was 4 degrees short of the mark.
At midday a squall line had developed in western Maryland. It is evident in the visible satellite image as bumpy clouds.
The 10 AM surface analysis shows a complex system of fronts affecting Mid Atlantic weather. A strong southerly flow of air ahead of the initial cold front is responsible for the unseasonably warm temperatures.
The complex system is also responsible for a very unstable air mass. The Storm Prediction Center has outlined an area along the East Coast, including the Mid Atlantic Region, as having a slight risk for severe weather Wednesday.
Check with http://wbaltv.com/weather for updates through the rest of the day.