374 FXUS63 KIND 131713 AFDIND Area Forecast Discussion National Weather Service Indianapolis IN 112 PM EDT Tue Oct 13 2020 .UPDATE... The AVIATION Section has been updated below. && .SYNOPSIS... Issued at 319 AM EDT Tue Oct 13 2020 Weak high pressure will slowly build today which will bring dry conditions to the area through Wednesday night. A much stronger cold front compared to the one that came through yesterday will arrive Thursday bringing a quick shot for light rain followed by much colder temperatures. Areas of frost look likely Thursday night and again Friday night. Dry weather returns for much of the weekend before another system arrives early next week bringing chances for rain. && .NEAR TERM /Today/... Issued at 319 AM EDT Tue Oct 13 2020 Any ongoing fog is expected to end shortly after sunrise as winds pick up and dew point depressions increase. Dry conditions expected for today in the aftermath of the weak frontal passage yesterday. In the aftermath of this front, pressure gradient forces remain fairly tight with a 1000mb surface low in the Upper Great Lakes region. This will combine with an 850mb jet of 35kts this afternoon to create fairly breezy conditions across central Indiana. A weak inversion just off the surface will limit the mixing down of winds but with the combination of the jet and strong gradients, occasional gusts of up to 30 mph are possible. Strongest winds will be across the northwest where the jet is expected to set up. In addition to the strong winds, afternoon RHs are expected to drop to around 25-30% which will lead to a slightly elevated fire danger. Conditions remain sub-criteria for a RFW, but will highlight the risk in HWO. Afternoon high temps will rise into the upper 60s to low 70s. && .SHORT TERM /Tonight through Thursday night/... Issued at 319 AM EDT Tue Oct 13 2020 Dry conditions will continue into the early short term period. Conditions for fog look less favorable tonight compared to the ongoing areas of fog as the low levels continue to dry out. Another 850mb jet will move across northern Indiana tomorrow afternoon. Thermal profiles look more promising for mixing, so plan on increasing wind gusts to around 30-35kts in the afternoon with the highest amounts along the western counties where the jet axis is expected to set up. Winds will gradually diminish during the overnight hours Wednesday night as a strong surface inversion sets in. By early Thursday morning, a strong surface low pressure will track across the Upper Midwest with a surface front associated with this low moving through central Indiana during the daytime hours. There is still quite a bit of model spread on how much moisture will be available but with ample lift, confidence is fairly high that at least some precipitation will fall. Confidence in timing is too still too low for any higher than Chc POPs at any given time. The front will quickly move through with dry conditions returning by late Thursday. Areas of frost look likely Thursday night as skies clear and temperatures crash. Highs will rise into the mid to upper 70s tomorrow, followed by the low to mid 60s on Thursday. Lows will fall into the mid 40s tonight and the low 50s Wednesday night. Thursday night, temperatures will fall into the mid 30s. && .LONG TERM /Friday through Monday/... Issued at 304 AM EDT Tue Oct 13 2020 Ensembles in good agreement in indicating a progressive nature to the flow across the area during this period. A rather deep trough will be in the process of passing off to the east on Friday. Ensembles suggest the main precipitation threat will have shifted off to the east by Friday morning. However, given the abnormally low heights associated with the passing trough, will have to monitor future model trends with respect to the potential for instability showers on Friday. The next trough is expected to move into the Plains and Midwest by next Monday. Ensembles suggest the precipitation threat, associated with a developing warm advection pattern, may arrive as early as Sunday, with the better threat by next Monday. For now, will continue to keep the forecast dry through Sunday, and go with chance PoPs by next Monday. May have to add PoPs for Sunday if ensembles trend towards the wetter solutions. && .AVIATION /Discussion for the 131800Z TAF Issuance/... Issued at 112 PM EDT Tue Oct 13 2020 Very dry column below 500 millibars lends high confidence that VFR conditions will dominate the TAF period with some increase in cirrus after 03z Wednesday. Southwest winds to 14 knots will gust to near 25 knots at KLAF. Winds will then drop off after 23z and especially after 04z-08z as surface high pressure moves over the Ohio and Tennessee Valleys. Winds will become light and variable or calm. Then, southeast and south winds will pick up again after 14z and especially after 17z, when mixing increases and surface pressure gradient increases ahead of another frontal system. Could see gusts 25 to over 30 knots then. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...White NEAR TERM...White SHORT TERM...White LONG TERM....JAS AVIATION...MK