443 FXUS63 KIND 290804 AFDIND Area Forecast Discussion National Weather Service Indianapolis IN 404 AM EDT Tue Sep 29 2020 .UPDATE... The AVIATION Section has been updated below. && .SYNOPSIS... Issued at 331 AM EDT Tue Sep 29 2020 An upper level system could bring some showers to northern parts of the area on Thursday, and then a low pressure system could bring more rain to the area around Sunday. Otherwise generally dry conditions with below normal temperatures are expected. && .NEAR TERM (Today)... Issued at 331 AM EDT Tue Sep 29 2020 Early this morning skies were mostly clear across central Indiana. An upper trough was back across Wisconsin into Iowa. Some cold advection aloft today will allow an increase in cloudiness as surface warming occurs. Meanwhile, the upper trough will move across the area during the afternoon. The result will be partly cloudy skies. There will be some instability around this afternoon, mainly across the far southeast forecast area. However, moisture is very limited across the area. Thus, while chances for a shower in the southeast are nonzero this afternoon, for the moment believe that odds are below mentioning in the forecast. There will be enough sunshine today to boost temperatures into the lower and middle 60s, close to the NBM forecast. && .SHORT TERM (Tonight through Thursday night)... Issued at 331 AM EDT Tue Sep 29 2020 The National Blend of Models initialization was accepted for most items. Warm advection will occur aloft tonight ahead of the next approaching system. This will bring some clouds to the area. On Wednesday, a surface cold front will move through, as some upper energy moves in aloft. This will bring some isentropic lift to the area, but once again the limiting factor is lack of moisture. Will continue with a dry forecast. A tightening pressure gradient will bring breezy conditions, and cold advection behind the cold front could bring some wind gusts around 30 mph down to the surface. Dry conditions will continue Wednesday night with the area between systems. A larger and deepening upper trough will move into the area on Thursday. This will bring some deeper moisture with it, mainly across the northern forecast area. Will have some low PoPs north. Thursday night, colder air aloft will move in. This will create lake enhanced showers across northwest Indiana. At the moment believe these will stay just northwest of central Indiana, so will go dry. Temperatures will get closer to normal on Wednesday ahead of the cold front, then return to below normal readings on Thursday as colder air flows in once again. && .LONG TERM /Friday through Tuesday/... Issued at 227 AM EDT Tue Sep 29 2020 At the start of the period, strong northwest flow will bring in much cooler than normal air to the area. Some models indicate some lake enhanced precipitation may reach the forecast area, but confidence remains low that anything more than clouds will reach as far as central Indiana. This cooler weather will continue into the weekend with the potential for widespread frost Friday night when mostly clear skies, light winds, and temperatures in the mid to upper 30s combine to create ideal conditions for frost formation. A strong upper level wave will approach the area Sunday with small chances for rain Sunday and Sunday night as a surface front interacts with the upper level forcing. Strong southerly flow ahead of the front should help provide enough low level moisture to get rain amounts around a half inch. Latest model guidance suggests there may be just enough instability for a few rumbles of thunder, but that may be a bit overdone so plan on keeping just a mention for rain. Dry weather is expected for the first part of the workweek after the system exits and high pressure builds. Temperatures will be below to much below average through the period. && .AVIATION /Discussion for 29/09Z TAF Update/... Issued at 403 AM EDT Tue Sep 29 2020 No changes needed to ongoing TAF. Previous discussion follows... Will continue to trend toward VFR conditions for the duration of the TAF period as high pressure strengthens over the region. SREF models indicate no increase in cloud cover at the critical ceiling levels early Tuesday morning. Meanwhile, winds will be up to 5 kts out of the west. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...50 NEAR TERM...50 SHORT TERM...50 LONG TERM....White AVIATION...TDUD/White