498 FXUS63 KIND 261336 AFDIND Area Forecast Discussion National Weather Service Indianapolis IN 936 AM EDT Sat Jul 26 2025 .KEY MESSAGES... - Heat Advisory across portions of central and southern Indiana through tomorrow evening - Dangerous heat continues into early next week with additional days of greater than 100 degree heat indices likely - Periodic showers and storms through the weekend with isolated flooding and strong winds && .FORECAST UPDATE... Issued at 936 AM EDT Sat Jul 26 2025 An abundance of mid and high level clouds lingered over much of the forecast area this morning from the remnants of early morning convection across the northern part of the state and additional thunderstorms currently over western Illinois near the Mississippi River. Have seen a few showers across the forecast area already otherwise it was dry. 13Z temperatures ranged from the mid 70s to lower 80s. Bit of a convoluted forecast for the rest of the day that starts with the ongoing cloud cover. More substantial clearing exists from central Missouri into south central Illinois with the expectation of that spreading east across the southern half of the forecast area by early afternoon. Further north however...the broad mid and high level clouds associated with the ongoing convection may keep skies in a mostly cloudy state well into the afternoon. This would likely have an impact on eventual highs and perhaps available instability for convection later on. Speaking of convection...mesoscale features will be critical again as they have been the last few days on where storms develop. A remnant outflow boundary from storms earlier this morning has settled in a west-east fashion south of I-70 and is likely influencing the isolated development we have already seen so far this morning across the central portion of the forecast area. This is likely to be a focal point for renewed convective development this afternoon as convective temps are reached. Convection will again be heavily driven by instability and of a pulse intensity in the absence of shear. While localized wet microbursts remain a threat from any collapsing downdraft...torrential rainfall and cloud to ground lightning will remain the primary concerns for outdoor activities this afternoon and evening. New model data this morning continues to highlight a potential for more organized convection to move into the Wabash Valley from the west by mid to late evening and will need to monitor trends through late day. Highs will again be in the upper 80s and lower 90s this afternoon... but will need to monitor cloud coverage as heating could be limited slightly over northern counties. Will maintain the Heat Advisory across the southern half of the forecast area with heat indices approaching 105 degrees. Zone and grid updates out. && .SHORT TERM (Today and tonight)... Issued at 255 AM EDT Sat Jul 26 2025 Surface analysis early this morning shows a poorly defined frontal boundary draped from Central IL northeast to northern Indiana and MI. Convection over IL was present near this boundary and was pushing northeast along it. High pressure was found north of the boundary over Ontario and a second area of high pressure was found over the southeastern states. The southern high was resulting in a continued lower level flow of hot and very humid gulf air streaming into the Ohio Valley. Aloft, water vapor imagery shows a plume of tropical moisture streaming across TX, northward to IA and MO, and then northeast to IL, NRN Indiana and MI. the ongoing storms were staying confined mainly to underneath this plume. An upper level high pressure system was found over the SE states, resulting in ring of fire like effects over IL into northern Indiana. Today... Little overall change will be expected today across Central Indiana. The very hot and humid air mass in place across the area will continue to control our weather as the upper high is suggested to strengthen and steer potential forcing dynamics and the tropical plume farther to the north. Forecast soundings once again show a favorable signature for diurnal convection with steep lapse rates and CAPE values over 2800 J/KG. Pwats also are favorable with values in excess of 1.90 inches. HRRR also suggests afternoon shower and storm development due to these favorable conditions. Thus will once again include afternoon pops for hit and miss diurnal storms. Heavy rain will be possible considering the very moist air mass. HRRR suggests storms dissipating by early evening. Again high dew points in combination with highs around 90 will result in heat index values in the low 100s. Ongoing Advisory will remain. Tonight... A few lingering diurnal storms will be possible in the evening before the rest of the evening looks to remain mostly dry. Models suggest an organized area of convection and forcing well to the north of Central Indiana, over northern Indiana and Michigan during the evening, However, the tail of this system may trigger some overnight convection across Central Indiana. Confidence for this is low, but given our continued warm and humid air mass, small chances for pops will still be necessary for now. Lows overnight will remain warm and humid, in the middle 70s. && .LONG TERM (Sunday through Friday)... Issued at 255 AM EDT Sat Jul 26 2025 For much of the long term, central Indiana will sit between an upper high meandering over the SE states into the central plains and a large upper low over Canada. This will place the area in a hot and humid pattern with almost daily chances for showers and storms. Severe weather looks unlikely with a lack of shear, but can`t rule out an isolated downburst causing damaging winds. Highs through midweek are expected to range from the upper 80s to low 90s. With ample humidity to continue, heat headlines will likely continue as heat indices near 100-110 will be probable. By mid to late next week, the upper low over Canada will dip southward, bringing cooler and drier air to the region. Highs for late week into the weekend may even max out in the upper 70s for a day or two, providing a relief to the heat. && .AVIATION (12Z TAF Issuance)... Issued at 534 AM EDT Sat Jul 26 2025 Impacts: - Scattered convection developing again this afternoon Discussion: Overall Little change in the ongoing TAF forecasts. VFR is expected for much of the period. Waning convection over IL and Northern Indiana has resulted in some high CI debris clouds. These clouds will drift across the TAF sites early in the forecast period. The very warm and humid air mass will remain over Central Indiana today, and once again forecast soundings are favorable for diurnal convection. As daytime heating begins, CU development will start by mid morning. By early afternoon VFR Cigs due to CU is expected. HRRR suggests isolated shower and storm coverage thereafter as highs in lower 90s are reached. Confidence for specific timing or locations of any storms is small, so just a period of VCTS has been used for now during the most favorable hours for storms. Any TSRA that strikes a TAF site may result in brief MVFR to IFR conditions. && .IND WATCHES/WARNINGS/ADVISORIES... Heat Advisory until 8 PM EDT this evening for INZ043>047-051>057- 060>065-067>072. && $$ UPDATE...Ryan SHORT TERM...Puma LONG TERM...KF AVIATION...Puma