651 FXUS63 KIND 231055 AFDIND Area Forecast Discussion National Weather Service Indianapolis IN 555 AM EST Thu Jan 23 2020 .UPDATE... The AVIATION Section has been updated below. && .SYNOPSIS... Issued at 321 AM EST Thu Jan 23 2020 Active weather is expected over the next 72 hours as an upper level low pressure system moves through the area. Precipitation will initially begin as rain today and tomorrow with some snow mixing in tomorrow night and Saturday. Little to no snow accumulations are expected at this time. High pressure will move in Sunday with dry conditions for much of next week before small chances for precipitation return for the later half of the work week. && .NEAR TERM /Today/... Issued at 321 AM EST Thu Jan 23 2020 Much of the period will be dry with some small chances for rain during the latter portions of the day as a strong upper level and associated surface cold front approach the area. Latest radar images show a few areas of light precipitation across central Illinois with some mixed precipitation falling. Over central Indiana, air near the surface remains too dry for anything to reach the ground. Saturation is expected across the western counties by mid morning and will reach the eastern counties by late this afternoon. In addition to the dry low level air, little upper level forcing is expected over the area today which will further limit precipitation chances. Overall, a few snowflakes may mix in this morning across the western counties, but otherwise rain is expected to be the dominant precipitation type with little precipitation accumulation. Fairly strong warm air advection will be in place today which will allow temperatures to rise into the upper 30s and lower 40s even with little to no breaks in the clouds. && .SHORT TERM /Tonight through Saturday Night/... Issued at 321 AM EST Thu Jan 23 2020 Active weather will continue into the short term period as a strong upper level low pressure and associated surface cold front move through central Indiana. By tonight, the atmosphere will be fully saturated with stronger upper level forcing in place as the upper low nears. This will lead to widespread light rain over the area through much of the night. The LLJ will be strongest further east into Ohio which is where the best moisture advection and highest rain amounts are expected. Confidence in rain tonight is very high and trended POPS near 100 to account for the high confidence. Rain will continue off and on into the day Friday as the dry slot works its way into central Indiana. Confidence in rain tomorrow is high with lower confidence in rain at any given point. A few snow showers may begin to mix in late Friday night as colder air works its way in on the back end of the system. Models show a good flow of moist air originating from the Atlantic Ocean and wrapping around the low to arrive in central Indiana by Saturday. Confidence that the moisture makes it this far is fairly low and if it does, it should remain light. Thermal profiles show that there may be a brief period where accumulating snow is possible Saturday morning, but will be strongly dependent on surface temperatures which confidence is low in at this time. Precipitation will end by Saturday night with dry weather for Sunday. Overall rain amounts will be around a half inch with some locally higher amounts in the eastern counties. Snow accumulations are expected to be less than a half inch with low confidence in any accumulations occurring. Temperatures will be above average through the period with highs in the upper 30s to lower 40s and lows in the low to upper 30s. && .LONG TERM /Sunday through Thursday/... Issued at 231 AM EST Thu Jan 23 2020 The national blend was accepted for most items. Starting Sunday, surface high pressure will build in from the west in the wake of the previous low pressure system, and will stick around for most of the Long Term. This will keep central Indiana dry, blocking moisture from the south. Afternoon high temperatures will be near to above average, with a slight uptick in temperatures towards midweek. Aloft, ridging out west will lead to a multitude of weak short waves, initiating in the interior Canadian Plains, and progressing southeast over the Midwest. Weak dynamics over the Midwest and a lack moisture will limit precipitation chances as these waves pass. By Wednesday, the surface high pressure weakens, allowing for more moisture to advect over central Indiana. For now, PoPs are kept low for Wednesday, as confidence remains low. The next best chance for precipitation remains Thursday as a more aligned upper- level trough and surface low develops over the Midwest. && .AVIATION /Discussion for 23/12Z TAF Issuance/... Issued at 537 AM EST Thu Jan 23 2020 VFR conditions expected for much of the morning. MVFR ceilings will start this afternoon. IFR ceilings likely late tonight into tomorrow morning. A low pressure system will progress eastward over central Indiana during the day. Snow showers are possible this morning at KLAF. Otherwise, precipitation will start for all sites later this evening with a gradual drop in ceilings throughout the night. Visibility will drop to MVFR as precipitation begins, and will continue for the rest of the TAF period. Winds will start out the southeast and will gradually shift eastward as the low approaches. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...White NEAR TERM...White SHORT TERM...White LONG TERM....Updike AVIATION...Updike