358 FXUS63 KIND 121429 AFDIND Area Forecast Discussion National Weather Service Indianapolis IN 929 AM EST Thu Jan 12 2023 .Forecast Update... Issued at 928 AM EST Thu Jan 12 2023 Light rain continues to move across central Indiana across a narrow axis of mid level lift as the bulk of the precipitation pushes east across Kentucky and southern Ohio. Made adjustments to the hourly POPs through the morning to try and fine tune precipitation timing and extent. With the elevated instability gone, also pulled the thunder mention through the rest of the day. In the aftermath of the heavier precipitation, the dense fog has cleared out with lowered visibilities of 3-6 miles continuing across the area. These lowered visibilities will continue for the next few hours with the lingering moisture, but increasing wind speeds will help further improve conditions. Latest ACARs soundings show that the near surface inversion has lifted to around 1000ft which is allowing for winds up to 30 mph to mix down and expect that inversion to slowly continue to lift and allow for more frequent gusts to 30 mph. Temperatures will slowly fall through the day today with the northerly component now to the wind with temperatures in the mid to upper 30s for much of the area by later this evening. No major changes needed other than fine-tuning POPs and Wx. && .Short Term...(Today and tonight) Issued at 612 AM EST Thu Jan 12 2023 Today... * DENSE FOG ADVISORY FOR NORTHEAST HALF OF CENTRAL IN THROUGH 9AM EST * Widespread rain arrives by 10-11z * Light scattered snow showers possible overnight Widespread dense fog is ongoing across much of central Indiana. ACARS soundings show a well mixed dry layer remains in the mid- levels with light surface winds. This combined with a highly saturated surface will keep dense fog around over the next few hours. Moisture advection ahead of an approaching low will saturate the aforementioned dry layer with widespread precipitation expected by 11z as the surface low moves across the Ohio River Valley. Look for visibilities to improve as rain, which could be heavy at times, moves in. Model soundings show weak elevated instability with the potential for some embedded thunderstorms within the strongest showers. A few CG lightning strikes will be possible, but most lightning should stay at cloud level. The heaviest precipitation is likely to be focused across the southern half of central Indiana where stronger forcing and PWATs near the 90th percentile will align. Look for QPF amounts between 0.50 to 1 inch over this area with lesser amounts further north. The surface low will continue deepening as it moves eastward with a tightening pressure gradient expected over central Indiana. Due to this, 30-35 mph gusts will be possible late this afternoon through midnight. Tonight... Rain will transition to a rain/snow mix and eventually all snow overnight as cold air advection filters in on the backside of the surface low. Precipitation will be light as this transition occurs due to drier pushing in aloft. However, a northerly wind will lead to a long fetch off of Lake Michigan late overnight and begin to increase low-level moisture. This combined with steepening lapse rates from CAA aloft should allow scattered lake enhanced snow showers to develop. Only light accumulations are expected on grassy surfaces. Cannot rule out slightly higher accumulations in some spots if banding sets up. && .Long Term...(Friday through Wednesday) Issued at 258 AM EST Thu Jan 12 2023 * Scattered snow showers and flurries Friday * Multiple chances for rain next week Highly amplified and chaotic upper flow pattern will continue through the extended period...as dry weather over the weekend will be bookended by snow showers and breezy conditions Friday as the system for late week pulls away to the northeast...followed by a pair of strengthening surface lows poised to track into the region next week that will flip the Ohio Valley back into an active weather regime. Cold air will have established over central Indiana by daybreak Friday as an upper trough amplifies to our east with precipitation lingering across the forecast area in the form of light snow. A trailing wave aloft on the back side of the parent trough will pivot across the region during the day Friday and will interact with lingering low level moisture to generate scattered snow showers and flurries. Model soundings show steep lapse rates through 850mb with the dendritic growth zone occasionally dipping into the top of the low level moist layer. This will be more than sufficient with ample forcing aloft courtesy of the upper wave to generate scattered snow showers. With N/NW flow through the low levels...potential is there for a lake effect component to the snow showers as well with some of the hi-res guidance hinting at narrow bands of snow showers tracking across the northeast half of the forecast area in particular. Expect to see light accumulations but they will be isolated and wherever heavier snow showers fall. While some locations may see little to no accumulation...other spots may see a dusting up to an inch. Will continue to fine tune the details over the next 24 hours. High pressure will swing across the eastern half of the country over the weekend with quiet weather and abundant sunshine for the Ohio Valley. As the surface high shifts east and return flow develops in tandem with ridging aloft...temperatures will warm from the 30s on Saturday to the 40s on Sunday. Low pressure will eject out of the central Rockies Sunday night... tracking northeast into the Great Lakes by Tuesday. Deep Gulf moisture will advect into the Ohio Valley ahead of the surface wave with widespread rain developing Monday into early Tuesday as the surface wave passes by to the northwest. There is potential for at least an isolated threat for thunder Monday afternoon and evening considering the dynamic nature of the system...but not enough confidence at this point to introduce a mention into the forecast. Weak high pressure will bring a brief reprieve from the unsettled weather Tuesday but chances for rain will once again increase by late Tuesday night and Wednesday as another strong low pressure system tracks across the eastern Midwest. Extended model guidance has yet to focus in on a consensus with the track of the system but at this point...it again would appear that the system is most likely to track to the northwest of the forecast area with rain and warmer temperatures for central Indiana for the middle of next week. Looking out beyond the 7 day period...there are hints of yet another storm system impacting the region for next weekend. && .Aviation...(12Z TAF Issuance) Issued at 556 AM EST Thu Jan 12 2023 Impacts: * Visibilities slowly improving through midday but generally remaining 2-3SM and lower * Widespread rain with embedded thunder this morning * Ceilings rising to MVFR by this evening * Light rain showers transitioning to snow showers overnight Discussion: Poor flying conditions will continue through much of the forecast period. A large area of rain with embedded thunder is overspreading the region early this morning and as it does...the dense fog that has blanketed the area since late Wednesday is lifting with visibilities rising to 1-2SM. This will continue through midday but expect visibilities will largely remain at or below 3SM before improving further this afternoon. Rain will become more scattered this afternoon with wind direction shifting to N/NW at all terminals as a cold front moves away from the region. Winds will be gusty at times and that will persist through tonight as well. As temperatures fall through the low levels tonight...rain will mix with then changeover to snow. Expect scattered snow showers late tonight and Friday with periodic visibility restrictions. MVFR stratus will continue overnight into Friday. && .IND WATCHES/WARNINGS/ADVISORIES... None. && $$ Update...White Short Term...Melo Long Term...Ryan Aviation...Ryan