554 FXUS63 KIND 111434 AFDIND Area Forecast Discussion National Weather Service Indianapolis IN 933 AM EST Tue Feb 11 2020 .UPDATE... The AVIATION Section has been updated below. && .SYNOPSIS... Issued at 158 AM EST Tue Feb 11 2020 High pressure will build across Indiana today providing dry weather today and tonight. A strong area of Low pressure will move through the Ohio Valley on Wednesday and Wednesday Night. This will bring chances for mixed precipitation to Central Indiana. A secondary cold front will then push across the state on Thursday afternoon...producing more chances for snow along with more winter like temperatures for the start of the weekend. Warmer temperatures are expected to return early next week. && .NEAR TERM /Today/... Issued at 158 AM EST Tue Feb 11 2020 Surface analysis early this morning shows high pressure in place across NRN MO and eastern IL...nosing NE to NW Indiana. Water Vapor shows a stream of tropical moisture stretching across TX to Kentucky and Tennessee then northeast to the middle Atlantic states. This will become more inportant on Wednesday afternoon and night. An upper short wave embedded within the tropical flow was producing some rain showers near the Ohio River. Models are in pretty good agreement...quickly moving the wave aloft east of the area and allowing the high pressure to the northwest to build across Central Indiana. Time heights and forecast soundings show subsidence today along with dry air within the lowest levels. Some mid and high level saturation is displayed...but this is primarily due to quick flow aloft along with an upper trough sagging out of the upper midwest. Thus will trend toward a partly cloudy to partly sunny day today. Given some weak cold air advection and northwest winds expected...will trends highs at or below the NBM. && .SHORT TERM /Tonight through Thursday Night/... Issued at 158 AM EST Tue Feb 11 2020 Very active weather is expected this period. Dry weather is expected to persist tonight as the surface high slowly pushes across the area reaching the middle Atlantic States on Wednesday. Forecast soundings and Time heights show little change from earlier in the day. Thus we will expect dry conditions tonight and into early Wednesday. As we reach Wednesday afternoon the deep trough and upper low in place over the American southwest is expected to dig and push east. This will change the orientation of the tropical plume of moisture that we currently see in water vapor imagery and direct it toward Central Indiana. This will result in ample moisture for the expected development of an approaching area of low pressure that will push across Tennessee and Kentucky on Wednesday afternoon and Wednesday Night. Time Highs and forecast soundings show a saturated column at that time along with good lift. GFS Pwats appear near 0.86 and the 290K GFS Isentropic surface shows excellent upglide within the system ahead of the trough along with specific humidities over 5 g/kg. Thus confidence for precip will be high on Wednesday afternoon and Wednesday night as these features come into place. Forecast soundings appear a bit more tricky when it comes to p-type. Soundings are hinting at surface temps near 0C...with warm air advection in place aloft. with such limited cold air in place within the lower levels...feel the main p-type on Wed will be rain. A mix or FZRA will be more likely farther north...LAF-OKK-MIE where the colder air will be a bit deeper. Warm air advection appears to persist Wednesday Night as the column appears to warm. Thus rain early on Wednesday night...expect north. By 12Z Thursday...the surface low will be well to the east of Central Indiana and cold air advection will be in place as the first of a pair of cold front will have passed. best moisture and forcing will have passed by 12Z thursday...however...overnight on early Thursday morning...all p-type should change over to SN. On Thursday afternoon and evening...yet another quick moving upper trough and secondary cold front will be poised to push across Indiana. This will introduce some arctic...winter air for the end of the week. Decent moisture still appears in place within the lower levels on Thursday morning as forecast soundings fall well below 0C and show saturation within the favorable dendritic growth zone of -10C to -20C. Thus will include pops with snow accumulations on Thursday morning as this secondary front passes. Headlines will be possible for this period...mainly Wednesday night through Thursday and coordination with surrounding WFO's remains ongoing. && .LONG TERM /Friday through Monday/... Issued at 235 AM EST Tue Feb 11 2020 Ensembles indicate a progressive, low amplitude, type flow across the area during the extended. A couple of rather weak short wave troughs may affect the area, one around Saturday, and another one around next Monday. At this point, neither of these disturbances looks like a big QPF producer. Will go with some chance PoPs for mixed precipitation for Saturday night into Sunday, to cover the first wave. Looks like there may a break in the precipitation threat Sunday night into Monday morning, before the next wave arrives Monday afternoon. The disturbance on Monday looks to be more of a rain threat, based on thickness progs. Previous forecast had PoPs in the forecast for much of the time from Saturday night through Monday. Decided to leave the PoPs as is for now, with the understanding that there may some timing changes going forward. May be able to eventually fine tune the PoPs later this week. && .AVIATION /Discussion for the 111500Z IND TAF Update/... Issued at 933 AM EST Tue Feb 11 2020 No changes needed to the TAF> Previous discussion follows... Issued at 533 AM EST Tue Feb 11 2020 Radar indicates some light mixed precipitation in the vicinity of the KBMG terminal until about 111300Z. Otherwise, ceilings above 050 expected to gradually scatter out from the northwest later today. Short term model guidance suggests there is potential for some cloud development around 025-030 this afternoon, but confidence is not particularly high at this time. Surface winds 320-350 degrees at 5-8 kts this morning will gradually back to 280-300 degrees at 9-13 kts this afternoon. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...Puma NEAR TERM...Puma SHORT TERM...Puma LONG TERM....JAS AVIATION...JAS/MK