Photo Courtesy: College of DuPage
Developing area of low pressure will move over the region tonight, and then high pressure builds in for the weekend off the coast.
Current satellite/radar shows a baroclinic leaf to our west, which is responsible for the precip currently moving into the region. 12Z surface charts had placed the center of low pressure over Ohio. Looking at the upper level pattern at 850mb, shows modest warn air advection over the region and also to our west as well. There is a broad trough at 500mb, with an embedded shortwave upstream of the trough axis which looks like our weather maker for Monday night into Tuesday.
12Z GFS, NAM, and ECMWF have similar solutions with a 500mb weak vort max moving across the region tomorrow, with the GFS and the ECMWF having the vort max a bit more robust then the NAM. This would support the higher precip amounts that the model solutions have compared to the NAM. There is some disagreement on the propagation of the shortwave for next week though. The GFS is quicker with the placement of the vort max compared to the other models, thus bringing the precip in earlier then the ECMWF.
Isentropic analysis at 850mb of both the NAM and GFS show a modest pattern setting up over the region throughout tonight. It then breaks down for the day tomorrow, but then returns on Sunday with an even stronger advection pattern due to the southerly winds bringing in moisture all the way from the Gulf of Mexico.