026 FXUS63 KIWX 251849 AFDIWX Area Forecast Discussion National Weather Service Northern Indiana 249 PM EDT Fri Jul 25 2025 .KEY MESSAGES... - Showers and thunderstorms are expected to continue to sprout and move through this evening and Saturday. While the severe weather risk is low, heavy rain leading to flooding is a possibility. Another chance for showers and storms exists for Sunday with flooding still possible. - Hot and humid conditions are forecast for Monday and Tuesday with highs around 90 degrees and dew points in the 70s. Heat indices over 100 are forecast for both days. && .DISCUSSION... Issued at 241 PM EDT Fri Jul 25 2025 With ridging over the southeastern US, relatively weak shortwaves move into the area between this afternoon and Sunday afternoon. Between 70 degree sfc dew points, 15-18C 850 mb dew points and PWATs between 1.5 and 2.5 inches (1.5 to 2.5 SDs above normal) all allude to a moist profile capable of heavy rain leading to flooding. Thunderstorms will continue to be possible during the aforementioned time frame and times of slow storm motion paired with training and favorable MBE vectors for training/backbuilding create an environment conducive to heavy rain and flooding. One positive is that the area only has CPEI3 in action stage or above river-wise so far, despite recent rain, and there`s only one line of above normal rainfall from LaPorte to Henry county. There are two favored locations for rain today and tonight, one south of US-24 and another along US-6. The rainfall that occurred last Saturday from LaPorte to Henry county may mean it takes less rainfall to cause flooding. LaPorte, St Joseph, Starke and perhaps some of Marshall county may need to be watched, but there is some question still around where the supposed "storm track" resides so will stand down from a flood watch. An area of 30 kts of effective shear depicted on the NAM late tonight and into Saturday could allow for more instances of severe downbursts from storms with better organization. This continued chance for rain makes deciding on a heat advisory for Saturday difficult with rain chances and the lingering possibility of debris clouds allowing for pockets of cooler temperatures. Saturday still is projected to have 70+ dew points and 850 mb temps greater than 18C, but the rain and clouds probably keep things cooler than is needed for the heat advisory. Substantial height rises take over Sunday as the ridge builds and there`s some southward tendency in the surface reflection as a shortwave dives southeastward Sunday night into Monday. This looks like rain generally shuts off as PoPs go from 30 to 40 percent to more like 15 to 25 percent. There is some disorganization as that aforementioned shortwave appears to dissolve as it traverses through the area. While some low level RH remains, the potential is there for Monday to see renewed chances for advisory and perhaps warning level heat and humidity. Even smaller chances for rain on Tuesday also keeps the high heat threat around with 90 degree temps and 70 degree dew points in store. During the early week next week, the wave guide shifts northward as the southeastern US ridge builds to more of a sprawling south-central US ridge. Finally, an eastern Canada upper low will be able to send cooler air towards US Wednesday/Wednesday night as the front crashes southward toward the area. Could see a few showers from that as the ridge breaks down and weak shortwaves approach from the northwest. A cool and dry period takes over to end the week and that continues into the next weekend. CPC has a below normal precip/temp lean for the first part of August. && .AVIATION /18Z TAFS THROUGH 18Z SATURDAY/... Issued at 1244 PM EDT Fri Jul 25 2025 Convective chances through the period remain the primary aviation weather concern. A couple of areas of greater convective coverage are currently expected this afternoon. One area is expected from Lake Michigan vicinity into far SW Lower MI/NW IN where some enhanced sfc convergence is possible given proximity of stalled frontal zone and the potential of some weak northerly flow off Lake Michigan. For this reason have maintained a TEMPO TSRA mention at KSBN later this afternoon/early evening. Confidence in thunder is slightly less at KFWA as more vigorous convection may develop south of the terminal where a differential heating forcing mechanism may be a factor. Will maintain a PROB30 TSRA mention at KFWA due to the slightly lower confidence. Showers and storms may increase in coverage again late tonight, particularly across far northern Indiana due to the approach of an upstream MCV across northeast Missouri. In terms of cigs, some pesky IFR cigs have persisted at KSBN through midday, with sfc obs generally supporting this preference for IFR cigs in a narrow west-east band near the stalled frontal boundary. Diurnal mixing should continue to lift these bases to MVFR over the next hour, before likely scattering to MVFR after 19Z or 20Z. Additional MVFR (possibly brief IFR) restrictions are possible later tonight in association with any heavier showers and storms. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...None. OH...None. MI...None. MARINE...None. && $$ DISCUSSION...Roller AVIATION...Marsili