Main area of rain Moving into the Region.

After hours of light shower activity, the main area of rain is finally shifting into our area from the southwest.  The rain will become heavier and more widespread as the evening progresses, becoming heavy by late evening.  As the rain becomes heavier, we have an increased chance for thunderstorms overnight.  Tonight, there are several factors that will support the chance of heavy rain and possibly localized flooding.  One is higher Precipitable Water values over the area, especially areas northeast of Fort Wayne.  Higher amounts of Precipitable Water in the atmosphere indicates the potential for heavy rainfall (generally rainfall amounts will be near the precipitable water value over a location, without the addition of other factors).  Another factor is convergence induced by convective processes and dynamic processes.  The convective processes that are causing convergence are higher values of Theta-E (measure of instability and buoyancy in the atmosphere) and moisture/warm air advection, which is also causing the air to become more buoyant and unstable.  One of the major factors associated with the convergence caused by dynamic processes is the jet stream.  The jet stream over us (or a branch of the jet stream), is causing upper level divergence over our area, which indicates low level convergence is occurring at the same time.  Convergence will cause a concentration of moisture over a smaller area, the corridor from Fort Wayne into Northwest Ohio.  The uplift with the convergence will cause thunderstorms to form, which will enhance heavy rainfall and possibly flooding.  Rainfall amounts from this evening to overnight will be from 1-2 inches area wide, with some areas picking up 2.5 inches (but this is very unlikely).  So expect rain to begin shortly and become more widespread and intense over the area especially by the late evening hours.  Overnight, thunderstorms are possible, with some producing intense rainfall for long periods of time.  I really don't expect much in the way of severe weather, expect for the possibility of flash flooding.  At this time, widespread flooding is really not expected because of near normal soil moisture conditions, while areas west of here have drier than normal soil moisture conditons.  According to forecast models, heavy rain/thunderstorms will occur into the early to mid morning hours tomorrow.  After that, conditions will generally clear up and by mid to late afternoon partly cloudy conditions will appear over some parts of the area, especially in areas farther west, as the main rain bands move into central Michigan.