The Mid-Atlantic remains under the influence of an Omega Block, which has brought a great stretch of weather to Maryland over the past week. An Omega Block is when the jet stream develops a flow that resembles the Greek letter Omega Ω.
When this blocking pattern occurs, air across the southwestern US is forced north towards Canada and then back south towards the southeastern US, forming a huge high-pressure "ridge" near the center of the country.
The region under the omega block experiences dry weather and light winds for an extended period of time - like we've been experiencing in Maryland.
The "dark side" of an Omega Block is when rain and clouds are consistent in association with the two low pressures on either side of the block. This set up has delivered over 10" of rain in the Houston area.
This block will begin to dissipate in the coming days and while this occurs, forecast models will have difficulty handling the changes. Therefore, the forecast may trend cooler this weekend as the system progresses. You can follow the changes here