Jet blue diverted to Richmond

I noticed jetblue flight 307 from LGB to Iad was divereted to Richmond this evening. I take this flight quite often and was wondering what would cause a flight to be diverted that close to its destination.

I think this was weather related. We had rain showers here (10 miles east of IAD) earlier. Looks like a nasty cell was in the Loudon county area and dissipated about the time the flight arrived into IAD.

WEATHER RADAR