830 FXUS63 KIND 101443 AFDIND Area Forecast Discussion National Weather Service Indianapolis IN 1040 AM EDT Wed Oct 10 2018 .UPDATE... The NEAR TERM and AVIATION Sections have been updated below. && .SYNOPSIS... Issued at 204 AM EDT Wed Oct 10 2018 Look for rain as strong cold front will push across Central Indiana today and tonight. Showers and thunderstorms are expected along and ahead of the front. Much cooler high pressure is expected to build across Indiana in the wake of the front. This will bring dry and much cooler weather through the end of the work week and into the weekend. More showers will be possible on Sunday as another front is expected to move swiftly across the state. && .NEAR TERM /Rest of Today/... Issued at 1040 AM EDT Wed Oct 10 2018 Satellite loop shows solid cloud deck in place across central Indiana this morning and more clouds streaming north into the area. These should continue to limit instability with the incoming cold front, and pulled thunder mention from the morning. Left isolated to scattered thunderstorms in with the overspreading rain showers expected through the afternoon hours due to the strength of the forcing. Looks like the cold front is a little slower than previously mentioned and won't be arriving in the west until later in the afternoon, but a prefrontal trough will provide forcing before then. Increased wind speeds and added some wind gusts for the day based on potential in soundings, and expect to see both prefrontal and postfrontal gusts around 16 to 25 kts. Previous discussion follows... The GFS and NAM suggest the cold front and associated tropical plume will advect east...pushing across central Indiana this afternoon. Excellent dynamics in play today for rain including a strong upper short wave and a strong cold front poised to push across the state. Forecast soundings show deep saturation by afternoon with pwats that over 2 inches. This is reflected of the very moist air mass that is in place across central Indiana. Forecast soundings show mainly a moist adiabatic column...thus instability appears rather limited...but a few rumbles of thunder cannot be ruled out. Also given the strength of the cold front and marginal shear available an isolated severe storm cannot be ruled out. Best chances for rain will be in the afternoon and evening...when the plume of tropical moisture and associated cold front is expected to pass. Thus will trend pops toward categorical at that point. Look for high temperatures to be achieved shortly before precipitation occurring...which should be near the middle of the day. Evaporative cooling along with the subsequent cold front will thereafter result in falling temperatures. Will stick close to the forecast builder blends for highs and will not exceed MAVMOS. && .SHORT TERM /Tonight through Friday Night/... Issued at 204 AM EDT Wed Oct 10 2018 The GFS suggests the surface cold front will be exiting Indiana near 00Z...and cyclonic lower level flow will be in place in the wake of the front. Forecast soundings continue to show a saturated column at 00Z...but that rapidly chances toward 06Z as strong subsidence and drying within the wake of the front take over. By 06Z forecast soundings show nearly a dry column as do the time heights as forcing is lost. Thus may keep some chances for pops...particularly across the eastern parts of the forecast are for a few hours after 00Z...but will quickly trend the forecast toward dry by 06Z. As for temps will trend lows close to the model blend values. Fall arrives in earnest on Thursday and will persist through Saturday. Strong Canadian high pressure is expected to build and settle across the Ohio valley through Saturday. Forecast soundings show a very dry column. Aloft a quick moving short wave is expected to push through the flow on Friday Night...but with little to no moisture available...thus should result in mainly a few clouds. Thus will trend this period toward partly cloudy days and mostly clear nights. Given the very cool air being introduced to the blends for the first time...will trend temps generally at or below the model blend. Coldest air of the season...lows in the mid 30s possible on Friday and Saturday Mornings. && .LONG TERM /Saturday through Tuesday/... Issued at 250 AM EDT Wed Oct 10 2018 Ensembles in good agreement in suggesting broad long wave troughing will reside over the eastern parts of the country during this period. Ensembles are in better agreement with respect to the timing of the next short wave trough, continuing to show the best precipitation threat from late Saturday night through Sunday night. Will keep PoPs going in those periods. Inherited rather high PoPs for Monday, but there are only a couple of ensemble members that suggest a precipitation threat will linger into Monday. For now, will reduce the Monday PoPs from what was in there earlier. May be able to take them out at some point if ensembles continue to trend away from a precipitation threat lingering into Monday. && .AVIATION /Discussion for the 101500Z TAFS/... Issued at 1040 AM EDT Wed Oct 10 2018 For the update...Brought ceilings down faster at KLAF and KHUF, but kept them higher for a few more hours at KIND and KBMG all based on upstream observations, current conditions and satellite loop. Added gusts to the TAFs for the afternoon hours and will also likely add some gusts behind the cold front during the overnight as well. Took VCTS out of the forecast for this morning with no instability but left it in for later this afternoon. Previous discussion follows... A couple of mid level vorticity areas, one currently moving through southwest Indiana, and another that will be moving into the area towards the midday hours, should result in increasing coverage of shower activity with time today in the vicinity of the terminals. Appears the best threat for lightning activity will be during the mid to late afternoon hours, when the cold front and upper trough approach. Brief IFR visibility restrictions and gusty shifting winds possible in and near heavier cells, mainly later this afternoon. Otherwise, should see ceilings gradually fall to around 020 from the southwest from the mid morning hours into this afternoon. Surface winds 150-170 degrees at 7-11 kts this morning will become 170-190 degrees at 9-13 kts by early this afternoon. Sporadic surface gusts 18-20 kts possible near precipitation areas. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...Puma NEAR TERM...Puma/CP SHORT TERM...Puma LONG TERM....JAS AVIATION...JAS/CP