Another round of heavy rain is expected across portions of the Mid West and Mid Atlantic, making existing flooding problems worse while creating new ones further east. More than 5″ of rain is possible over the next 7 days over portions of Oklahoma, Arkansas, Missouri, Illinois, Indiana, Ohio, and West Virginia. Portions of New Jersey, Pennsylvania, Maryland, Delaware, and Connecticut could see over 2.5″.
The large-scale pattern for much of the Sunday to Thursday period will feature a relatively fast and quasi-zonal mid/upper flow from the central Plains to the East Coast south of a longwave trough in eastern Canada. Several low-amplitude perturbations will progress eastward in the faster midlevel flow atop a quasi-stationary front from the Midwest and Ohio Valley east-northeast to the Mid-Atlantic and New England. To the south of the front, low-level warm/moist advection will continue through the period to the west of a broad subtropical ridge in the western Atlantic located between the southeastern U.S. and Bermuda. As the flow meets the quasi-stationary front and midlevel perturbations, bouts of convection will initiate and propagate along the surface front. Computer forecast guidance suggests this front will stall from Oklahoma to the Ohio Valley, leading to a prolonged wet period.
With rain forecast to fall over the same areas over and over again, flooding threats will increase throughout the week. The National Weather Service reminds people in these areas: turn around, don’t drown; never drive through flood waters.