Expires:No;;149986 FXUS63 KIND 131859 AFDIND Area Forecast Discussion National Weather Service Indianapolis IN 259 PM EDT Mon May 13 2024 .KEY MESSAGES... - Showers and a few thunderstorms expected through Tuesday - Up to around one inch of rain expected but locally higher amounts possible - Rain chances return Thursday into Friday, again early next week. && .SHORT TERM (This evening through Tuesday)... Issued at 258 PM EDT Mon May 13 2024 Rest of This Afternoon... Some weak lift ahead of an approaching upper system will work with some limited instability to produce scattered showers and some thunderstorms, primarily across the far western portions of central Indiana. Will go with primarily chance PoPs west. Satellite shows some holes developing in the clouds, so temperatures still look to remain around 80 at most locations. Tonight... Some upper energy rotating around the approaching upper system will bring scattered to numerous showers to the area this evening, then some better forcing will arrive late tonight. Moisture will be plentiful. Will go mainly chance or low likely category PoPs this evening, then increase to likely or higher PoPs overnight as the better energy moves in and interacts with the moisture. With clouds and some rain around, low temperatures will be around 60 degrees. Tuesday... The better forcing that arrives late tonight will continue into Tuesday morning. Will continue with higher PoPs then. There may be a relative lull early in the afternoon, then as heating occurs, additional showers and some thunderstorms will develop with the heart of the upper system arriving. Will continue with higher PoPs. At the moment, instability and shear look low enough to keep severe storms at bay. However, locally heavy rain remains a threat with the plentiful moisture. HREF local probability matched means show some potential for localized amounts over 2 inches. Clouds and rain will keep temperatures lower, with highs in the lower 70s expected most areas. && .LONG TERM (Tuesday night through Monday)... Issued at 258 PM EDT Mon May 13 2024 Active weather looks to continue through the long range with multiple storms systems possible. As of right now, no organized severe weather appears likely. SYNOPTIC OVERVIEW Aloft, the polar jet stream looks to remain at least moderately amplified to at times quasi-zonal. The subtropical jet is likely to remain separate across the southern states. This disconnection should preclude significant moisture transport northward. Nevertheless, waves embedded within the broader flow should pass through the Midwest with some regularity. These waves are modeled to take on a generally west to east path, which makes sense given the lack of phasing and quasi-zonal nature of the jet stream. Like today's system, enough moisture should be present for scattered showers and thunderstorms. The next wave in the series (after today's) arrives late this week around Thursday or Friday. Flow aloft looks rather weak and model soundings are nearly moist adiabatic. Showers and storms are still possible, given synoptic scale forcing...but the weak lapse rates and lack of wind shear will limit severe potential. The third system in the series arrives early next week, Monday or Tuesday. Model consensus diverges quite a bit by this point, however, so besides rain chances not much can be said about how this system will play out. Beyond that, ensemble guidance hints at broad troughing over the western states and into the Plains as we close out the month. That could allow the active pattern to persist for another week or two. The overall signal is not terribly strong, however. FORECAST CONFIDENCE Confidence through the period is average. Model guidance tends to be in agreement through the remainder of this week but diverges over the weekend. By next week, only a loose signal remains and it's hard to draw any conclusions when guidance shows such a variety of outcomes. Still, the overall picture looks a bit more active than normal (CPC 8-14 day outlook showing wetter than normal conditions). Lack of significant ridging should keep temps near normal for the most part. && .AVIATION (18Z TAF Issuance)... Issued at 1259 PM EDT Mon May 13 2024 Impacts: - Scattered showers this afternoon becoming numerous at times tonight and Tuesday. Some embedded thunder. - IFR conditions developing near sunrise Tuesday Discussion: Scattered low level and broken mid to high level clouds will continue through the afternoon, but during the night ceilings will gradually fall, reaching IFR at most sites by 12Z Tuesday. These will lift back to MVFR by 18Z Tuesday. Thunder will be scattered enough to not be mentioned within the TAF. Uncertainty remains on coverage of showers tonight, but they will be scattered coverage at least. && .IND WATCHES/WARNINGS/ADVISORIES...None. && $$ SHORT TERM...50 LONG TERM...Eckhoff AVIATION...50