NZUS99 KIND 311927 WRKSRT Rest of this afternoon... Subtle shortwave trough will continue to push east through the lower Great Lakes. Ample elevated instability (MUCAPE around 1000 j/kg) and limited instability will support a threat for scattered thunderstorms with small hail, gusty winds up to 45 mph and locally heavy rain for the next 1-3 hrs before weakening and ending from the west by 22Z. Tonight... Thunderstorms have begun to develop along a line from the western Chicago Suburbs back towards the Quad Cities. This activity is forming in a region of deep moisture convergence ahead of the main frontal boundary. Expected storm motions and current location agree with bulk of CAM guidance which moves this activity into far NW portions of central Indiana around 00Z. Similar to this mornings activity, threat will initially be large hail thanks to steep mid level lapse rates up to 7.5 C/KM. Elevated TS activity that moved through NW portions of the forecast area in the last 1-2 hrs has stabilized the BL. However, sufficient heating should redevelop before 00Z that near surface based parcels will support an additional threat for damaging winds. Activity will also be working with around 1.3 inch PWAT, which combined with slow storm motions will lead to threat for locally heavy rainfall. The threat for severe down to I-70 per recent SPC day 1 outlooks seems a little too far south given the slow storm motions and increasing cinh with southward extent. However the WPC day 1 marginal location looks reasonable. As the cold front accelerates southward later tonight, aided by CAA of Lk. Michigan, expect the greatest the for heavy rain to gradually shift south towards I-70 by 12Z Wednesday. Wednesday... Given strong convective overturning and weakening mid level lapse rates owing to building heights and latent heat processes, thunderstorm activity will continue to weaken and diminish in coverage during the morning. However, strong deep convectively enhanced frontal convergence aided by 30-40 kt 850mb jet will support the threat for multiple rounds of heavy showers along the frontal boundary during the day. Uncertainty exists on the exact QPF amounts, so decided to not hoist a Flood Watch, but over 1 inch of QPF is possible between 12-00Z. Expecting the frontal boundary to push much further south than NBM guidance and thus have undercut highs by 1-2 categories, remaining in the 40s/50s along and north of I-70. Wednesday night... Frontal boundary will lift northward as a warm front as strong pressure falls develop associated with another shortwave trough digging southward through the rockies and surface low pressure intensifying over the high plains. Showers and isolated TS chances will end quickly from the south early in the period as the front moves north of the CWA by 06Z. In fact Wednesday's high temps for most areas north of I-70 will occur just before 04Z. Thursday and Thursday night... As the next shortwave kicks eastward into the plains into the western Great Lakes, an associated frontal zone will push eastward to near the upper MS river by Thursday afternoon. Early morning TS over the Ozarks may move far enough east to aid in a convective outflow boundary ahead of the primary frontal forcing to support renewed convection along this boundary by afternoon just west of central IN. With little to no mid level height falls, soundings indicate substantial inversion centered around 500 mb robbing a deeper CAPE profile. Thus the slight risk has a lot of conditional nature to it, with many negatives limiting the threat at the moment. NBM Pops were lowered some, but possibly not enough given the limited deep forcing and marginal instability.