713 FXUS63 KIND 260651 AFDIND Area Forecast Discussion National Weather Service Indianapolis IN 251 AM EDT Sat Aug 26 2023 .Short Term...(Today and tonight) Issued at 251 AM EDT Sat Aug 26 2023 - Cooler but still warm today. - Cooler and less humid tonight. Surface analysis early this morning shows a broad, poorly organized, weak trough stretching from the northeastern United States to the middle Atlantic states, before turning west to WV, Nrn KY and southern Indiana. Convection was found early this morning over southern Central Indiana near the trough, but this feature was quickly diving southeast. Radar trends also show a weakening trend with the system. A large and broad area of high pressure was found over the northern plains. This feature was helping to push the trough farther south along with the hot humid air. This pattern was setting up for weak north or northeast surface flow across Central Indiana. Aloft, water vapor showed strong ridging in place over the Rockies, with NW flow aloft stream across the upper midwest into the Great Lakes and Ohio Valley. Strong Subsidence was found over MN and WI. Today... Models today show the high pressure to the northwest pushing east across the Great Lakes, keeping NE surface flow across Central Indiana. This in turn will help to continue to push the disorganized weak trough farther south, and away from Central Indiana. Aloft, NW flow remains prevalent and little in the way of forcing dynamics appear to push across Central Indiana. After this early morning convection exits, forecast soundings trend toward a dry column through the day and strong mid level subsidence over WI is shown to push SE toward Central Indiana. Forecast soundings show convective temps in the upper 80s, so a few CU could be possible this afternoon, but overall, a partly cloudy day will be in store. Cold air advection is in place today. 850MB temps are falling about 3C to near 15C today and this is much cooler than Friday. Thus highs in the middle to upper 80s will be expected. Tonight... The models continue to show slow cold air advection from the northeast overnight and this looks to continue into Sunday. Northwest flow aloft on the lee side of the strong ridge over the Rockies looks to continue also and little in the way of forcing dynamics appear to pass. Forecast soundings show a very dry column with strong mid level subsidence shown creating a very dry mid level. Thus will continue with a mostly clear sky as any diurnal CU will be lost in the evening. Given the less humid dew points in the lower 60s arriving across the area, lows in the lower to mid 60s will be expected. && .Long Term...(Sunday through Friday) Issued at 251 AM EDT Sat Aug 26 2023 * Quiet and seasonably pleasant through the coming week. Despite typical model suite disagreements, particularly with the handling of possible tropical remnants late in the week, broad agreement can be found in the overall thrust of the long term forecast that conditions should be fairly quiet and seasonably pleasant through the week. The primary upper level ridge that brought the intense heat and humidity to the area in the last several days is expected to continue to weaken and retreat westward, leaving central Indiana largely under the influence of cooler northwest flow aloft and multiple areas of surface high pressure, with the primary baroclinic zone reinforced well to our south much of the week. If there were a window for precipitation chances, it would most likely be Tuesday afternoon and evening with the passage of a very weak cold front, although the upper level forcing is displaced to our north over the Great Lakes, and guidance generally keeps us dry. Later in the week, large disagreements are noted in model handling of possible tropical remnants, but even the far more westerly GFS keeps the precipitation associated with this system to our east and southeast, thus a dry forecast will remain throughout the long term. Temperatures and particularly dewpoints will be significantly more pleasant for the last week of climatological summer, with highs generally in the mid 70s to mid 80s, and dewpoints as much as 10-25 degrees below their highest readings in recent days. && .Aviation...(06Z TAF Issuance) Issued at 1253 AM EDT Sat Aug 26 2023 Impacts: * Thunderstorms will impact the BMG Taf site for the first few hours of the TAF period. * Otherwise VFR Conditions will be expected. Discussion: Radar shows convective cluster over SW Central Indiana, pushing southeast within the flow aloft along an axis of instability near the surface trough. These storms are projected to push southeast across the BMG TAF site through the first hour of the TAF period. HRRR suggests this convection should exit BMG and weaken with its SE propagation through 09. Thus have used a prevailing TSRA at BMG for the first hour, but trended to VFR conditions after 07Z-08Z. Cooler temperatures on northerly winds associated with high pressure is expected to arrive on Saturday. Forecast soundings and time heights show a dry column through the rest of the TAF period as mid level subsidence is show to build across the Taf sites through the day. Some VFR afternoon CU will be possible, but any CIGS will remain VFR. && .IND WATCHES/WARNINGS/ADVISORIES... None. && $$ Short Term...Puma Long Term...Nield Aviation...Puma