045 FXUS63 KIND 010617 AFDIND Area Forecast Discussion National Weather Service Indianapolis IN 217 AM EDT Sat Apr 1 2023 .Short Term...(Today and tonight) Issued at 217 AM EDT Sat Apr 1 2023 Deep closed low will progress eastward across the southern Great Lakes today. Another vort maxima lobe will rotate through providing forcing for ascent, along with residual low level moisture and steep lapse rates will result in scattered showers developing by mid- morning through afternoon. Given the shallow convective nature, and thermal profiles, it is possible that some graupel could briefly mix in shortly after development in the late morning. This precipitation will primarily be across the northeast half of the area into the evening. Preceding this, a cold front will move through during the early morning, and as soon as we start mixing into very strong wind aloft (i.e., 90-kt 700-mb jet core) strong gusts will start. We will continue the Wind Advisory, though as the midlevel speed max moves east, wind gusts may lessen some during the afternoon, so gusts up to 50 mph may primarily be through early afternoon before subsiding. Cold advection should hold temperatures in the low to mid 40s during the afternoon. && .Long Term...(Sunday through Friday) Issued at 217 AM EDT Sat Apr 1 2023 We will continue in a progressive low amplitude flow pattern that will evolve to split flow before becoming quite amplified by Tuesday. This is as an impressive deep trough evolves over west and central CONUS. Before this happens, one low amplitude wave will interact with returning moisture to bring some rain Monday into early Tuesday. As strong warm/moist advection regime evolves preceding the intense mid-latitude system to our west on Tuesday, more rain will develop. We are growing increasingly concerned about episodic severe weather across the region, though the details on timing and specifically which areas are impacted the hardest are unclear at the moment. Current thinking is a dangerous setup of very broad warm sector with anomalous moisture and broad low-level jet/strong mass response to the main mid-latitude system will bring a risk of severe storms to Indiana at least with the frontal passage into Wednesday. There may also be severe thunderstorms in our area preceding this with either (1) the warm advection regime, or (2) associated with a weak midlevel perturbation that moves out of the Arklatex region Tuesday. The ceiling for this event is high across broader region, with the potential for significant severe and tornadoes. This may primarily be centered west of Indiana, but these details will become more clear over the next couple of days. The synoptic pattern after this system into the latter half of the week is a little more uncertain, given growing spread in ensemble spaghetti plots and cluster analysis. One possibility is for a lifting track and quick modest midlevel height rises keeping temperatures at least at climo if not slightly above. We would generally be dry as west-northwesterly flow pattern would suppress deeper moisture to our south and we would generally experience a drier continental air mass. Weak perturbations would only bring brief generally light precipitation events into next weekend. && .Aviation...(00Z TAF Issuance) Issued at 646 PM EDT Fri Mar 31 2023 Impacts: -Southerly wind gusts to 40kts through the TAF period, brief westerly gusts in excess of 50kts during line of storms. -MVFR cigs to briefly IFR cigs this evening -Line of storms expected from 02Z to 05Z, IFR vsbys during rain. -LLWS through the TAF period. Discussion: A line of storms is expected to impact the terminals between 02Z and 05Z with the potential for wind gusts in excess of 50kts. Gradient winds outside of storms will gust to around 40kts at times, especially after 05Z. Vsbys will remain VFR outside of the heavier rain. Cigs will remain MVFR through 05Z with low VFR conditions afterwards. LLWS will be a concern with a very strong LLJ even with surface gusts to 40kts. Winds will then gradually become more westerly and eventually northwesterly tomorrow afternoon. && .IND WATCHES/WARNINGS/ADVISORIES... Wind Advisory until 6 PM EDT this evening for INZ021-028>031- 035>049-051>057-060>065-067>072. && $$ Short Term...BRB Long Term...BRB Aviation...White