Rain chances return overnight and to end the week; ‘Northwest’ flow pattern coming

SHOWERS AROUND OVERNIGHT
Rain chances remain minimal through sunset. Any out door plans area go this evening but the showers and a few thunderstorms will increase overnight.
An area of low pressure currently over Missouri will move slowly east overnight. scattered showers and a few thunderstorms will develop and migrate north into south-central Indiana after 12 am. During the overnight and early Thursday the rain threat is directed with better coverage along and south of I-70.
COLD FRONT FRIDAY BRINGS NEW RAIN CHANCE
If you are looking for some rain and not seeing much the past few days, there will be another chance Friday. The high level of humidity combined with an approaching cold front will ignite showers and thunderstorms Friday afternoon. Locally heavy downpours are possible but these are looking selective and may only cover 20-30% of the area.
SUMMER 2017
Nearing the half way point of summer (35 days in) we are running 1-degree cooler than last summer and have only had 2 90-degree days.  To date we average 4 90's and last year we had already 8.  While scorching heat hasn't developed we are running above normal.  60% of the days since June 1st have been above normal.
NORTHWEST FLOW
The upper level winds will align in what meteorologist call a 'Northwest Flow' pattern starting this weekend.  An intense HOT DOME (air sinking and heating under a upper level high pressure) will develop out west and expand north through the middle of next week.  While the west bakes the jet stream will buckle and produce a jet stream that dives southeast from the Upper Midwest.  This is where the name comes from and the northwest current of jet stream winds will carry milder air into the eastern U.S.  There is debate as to how long the patter will last and if and when the heat or HOT DOME expands east.  At this distance we are favoring normal to below normal temperature highs early next week.