Radar & lightning: Latest D.C. area radar shows movement of precipitation and lightning strikes over past two hours. Refresh page to update. Click here or on image to enlarge. Or see radar bigger on our Weather Wall.

A very pronounced “back door” cold front will cut through the region tonight, dropping temperatures substantially.  Ahead of the front this evening, showers and storms are possible.  Behind the front late tonight into Thursday, it’s damp and unseasonably cool.

Through Tonight: Scattered showers and storms are possible this evening, with chances varying from 40 percent north of the District to 60 percent south of the District.  While there’s very little activity early this evening, we may see an increase as the front draws closer after 6 or 7 p.m. – but activity should still be scattered, as opposed to widespread.

Until around midnight, it’s fairly mild, but as winds start to come in from the east off the ocean, it turns cool and clammy by morning with pockets of light rain and drizzle (60 percent chance).  Lows are in the mid-50s to the north to near 60 south.

Tomorrow (Thursday):  Raw and cool, with areas of rain and drizzle.  Highs are some 20 degrees below today’s levels, only in the low-to-mid 60s.  Winds are from the east around 10 mph.  Rainfall totals are likely around one-quarter inch.

See Dan Stillman’s forecast through the weekend. And if you haven’t already, join us on Facebook and follow us on Twitter . For related traffic news, check out Dr. Gridlock.

Pollen: Counts are incomplete due to last night’s rain, but tree and grass counts remained HIGH as of this morning.

Back door front: On a weather map, the cold front moving into the region is hard to miss.  Look at the variation in 4 p.m. temperatures between southeast Virginia (close to 90) and eastern New England (40s)!