000 FXUS63 KIND 011434 AFDIND Area Forecast Discussion National Weather Service Indianapolis IN 934 AM EST Fri Dec 1 2023 .Key Messages... - Rain Ending late this morning; then lingering drizzle - Additional rain chances Saturday night into Sunday and again Monday night into Tuesday - Return to near normal temperatures next week && .Forecast Update... Issued at 933 AM EST Fri Dec 1 2023 Surface analysis this morning shows low pressure in place over Central Missouri. A warm front extended northeast from the low across Central IL to northern Indiana and SE MIchigan. Water Vapor imagery shows a short wave over Illinois pushing northeast within a quick SW flow aloft across the region. Water Vapor imagery shows some dry air intruding into the system from the southwest across southern IL and SW Indiana. Radar shows the bulk of the precipitation shield that has passed over Central Indiana has pushed to the northeast, with the back edge of precipitation pushing northeast across Central Indiana. Winds were from the south. GOES16 shows extensive cloudiness across the Ohio and middle Mississippi Valleys within the vicinity of the surface low. This afternoon, the bulk of the precipitation should come to an end. Dry air will be intruding into the system aloft. This can be seen within the water vapor imagery and forecast soundings show the beginning of a top down subsidence taking place late this morning. The weak short wave also responsible for the bulk of the lift to the northeast will also be quickly departing to the northeast within the quick SW flow aloft. Thus much of the measurable precipitation with this system will be coming to an end late this morning. Forecast soundings and Time heights keep saturated lower levels through the day with a mid level inversion in place. The low pressure system over MO is expected to push toward Central Indiana this afternoon. This may result in weak lift with lower level saturation which will be a favorable set-up for drizzle or perhaps a rain shower that results in one or two hundredths of precipitation. Thus we will trend pops downward this afternoon as the dry air arrives aloft and the stronger lift departs, but keep a pop mention along with the ongoing drizzle as the surface low begins to arrive. Given the expected clouds, highs in the middle 40s or nearly steady state temperatures will be expected. Overall, the ongoing forecast appears in good shape. && .Short Term...(Today and tonight) Issued at 235 AM EST Fri Dec 1 2023 A fast moving shortwave trough with coupled jet structure is in the process of dampening, and its attendant surface low will lag and weaken as well. Its period of stronger isentropic ascent and warm/moist advection-driven rain shield will exit around midday. Total rainfall maxima should be north and south of central Indiana. North, where isentropic ascent is prolonged before midlevel dry conveyor belt arrives, and south closer to deep/anomalous moisture within the eastward bending branch of the warm conveyor belt. There will be little/no scouring of low-level moisture in the wake of the deeper ascent shifting northeast. Convergence from aforementioned weakening surface low maintained by quasi-perturbed strong westerlies aloft will aid in at least periodic drizzle continuing at least into the evening. Veering low-level flow, slightly drier low-level air mass, and overall lessening ascent should result in cessation of any lingering light precipitation later in the night. && .Long Term...(Saturday through Thursday) Issued at 235 AM EST Fri Dec 1 2023 On Saturday, there appears to be enough residual low-level moisture and heating/mixing for at least periodic broken stratocumulus, but subtle mid-upper riding should keep us dry. Saturday night, another fast moving amplified shortwave trough will bring a period of sufficient ascent and moisture advection for another round of rain. This should peak in the predawn hours through late morning with improving trends for the latter half of Sunday. Two more distinct shortwave troughs cross through in rapid succession Monday and late Tuesday. By this time, the eastern mean ridge will have broken down some and deeper moisture will be shunted eastward. Moisture anomalies are neutral at best over our region and any precipitation that occurs during this period is expected to be light. The synoptic pattern does not support much flux in temperatures with no opportunities to dislodge colder higher latitude air mass, and likewise no noteworthy warm advection regimes. Spaghetti plots become more chaotic late in the week, but medium range guidance does show some form of shortwave trough in the Thursday/Friday time frame, though out of phase among ensemble members as well as different amplitudes. The deterministic GFS is more aggressive earlier with QPF relative to many of its ensembles and nearly all of the EPS members, so probabilities for precipitation are low during this period for now and will be refined once model spread lessens. Early indications for the Day 8-14 period are for continues amplified progressive split-flow with a signal for at least a period of ridging and warmth, along with periodic precipitation. && .Aviation...(06Z TAF Issuance) Issued at 1242 AM EST Fri Dec 1 2023 Impacts: - Rain and deteriorating flying conditions - Wind gusts may return later this morning - IFR prevailing even after the rain stops Friday afternoon Discussion: Steady rain is expected through the first part of Friday with IFR conditions. Even after the rain stops, IFR conditions will likely prevail through the end of the TAF period. Mixing and momentum transfer may result in at least occasional wind gusts to around 20 knots later this morning. && .IND WATCHES/WARNINGS/ADVISORIES... None. && $$ Update...Puma Short Term...BRB Long Term...BRB Aviation...BRB