189 FXUS63 KIWX 092321 AFDIWX Area Forecast Discussion National Weather Service Northern Indiana 721 PM EDT Tue Oct 9 2018 .SYNOPSIS... Issued at 713 PM EDT Tue Oct 9 2018 Expect partly to mostly cloudy skies and lows in the 60s tonight. A cold front will bring rain and chances for thunderstorms Wednesday. An isolated strong to severe storm is possible Wednesday afternoon and evening along with locally heavy rainfall. Highs Wednesday will be in the 70s. Expect more fall like weather through next week, with highs in the 50s and low 60s and lows in the 30s and 40s. Frost is expected on Friday night, when lows drop into the low to mid 30s. Additional chances for rain will return Sunday into Monday. && .SHORT TERM...(This Evening through Wednesday) Issued at 339 PM EDT Tue Oct 9 2018 Quiet weather is expected tonight, outside of a few isolated showers. We'll have one of our last warm evenings of the season, with lows only dropping into the 60s. After the unusually warm, but largely quiet weather today (thanks to an expansive upper level ridge) we turn our attention to an approaching low pressure system, which will impact our area Wednesday. A deep mid-level trough is centered over the west-central US, with the corresponding surface low taking shape near Oklahoma. Models bring this low northward along a stationary front from now until Wednesday morning, eventually centering it over Iowa by 12z. From there, it lifts northeastward into Upper Michigan by Wednesday night, and into Ontario/Quebec by Thursday afternoon. This brings a cold front to our western doorstep by Wednesday afternoon-and that will be our focus for precipitation through the short term. Expect southerly winds to increase and become gusty Wednesday as the pressure gradient between the approaching low and the high to our southeast increases. Better synoptic support with the mid-level trough and increased moisture transport arrive ahead of the surface cold front (prefrontal trough) Wednesday, thus have pops increasing from mid-morning until Thursday night(most models shift the front out by 12z Thursday morning). Think the main threat with this system will be heavy rain given that PWATs are around 2".The good news is that it appears to move through rather quickly-so the flooding threat would be more for urban areas and low lying, poor drainage locations. An isolated strong to severe wind gust with any thunderstorms that manage to develop is not out of the question either, given the stronger LLJ just off the surface, stronger synoptic forcing, and the higher PWAT values. The limiting factor, as it often is around here, is the instability. MU/SFC CAPE values struggle to even get above 500-800 J/Kg. SPC has much of the CWA in a marginal risk for severe storms, which I think appropriately covers the threat. If any manage to develop, it looks to be a pretty isolated threat. Highs on Wednesday will be in the 70s, and then it's downhill temperature wise after that. && .LONG TERM...(Wednesday Night through Tuesday) Issued at 339 PM EDT Tue Oct 9 2018 Wednesday's system will usher in the more fall-like conditions, with highs only reaching into the 50s and low 60s starting Thursday and continuing into Tuesday of next week. Low temperatures will plummet into the upper 30s and 40s for the most part, but Friday night we could see lows in some areas drop to around 33-35. Gardeners, prepare your plants: frost is looking to be more and more likely. High pressure building in behind the cold front Wednesday night will keep things mostly dry through Saturday night, with the exception of Friday evening in our far northeast where we have a 20 percent chance of showers associated with a shortwave passing through Michigan. The remainder of the long term forecast is pretty muddled, as models struggle to deal with remnants of Tropical Storm Sergio and upper level trough (or closed low depending on the model)sliding across northern Ontario/Quebec. GFS is faster with bringing both the remnants and the northern trough eastward. This would bring a cold front through Sunday and shunt the remnants mainly to the southeast of our area (with the exception of northwest Ohio). The ECMWF suggests a slower solution, with the remnants lifting into our area just ahead of that front-which results in a more consequential rain event that continues from Sunday evening through Monday night. Kept pops all capped at 50% given large discrepancies in the models right now, but it is something to keep an eye on. High pressure returns late Monday night into Tuesday (models agree for now), so have left out any pops until Tuesday evening in the far northwest, when a surface low crosses into MN/western Lake Superior, bringing low precipitation chances to our far northwest. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening) Issued at 713 PM EDT Tue Oct 9 2018 VFR to start the period but conditions expected to deteriorate rather quickly Wednesday mid to late morning. Lower ceilings should invade rather quickly with MVFR then IFR likely by late morning or early afternoon. Rain should also spread north quickly. TSRA chances remain rather low with very limited instability so did not introduce into terminals given small chances. Best chances would likely be on leading edge of initial rain surge then again along or just ahead of cold front late afternoon into early evening. Did introduce wind shear for marginal conditions overnight at KSBN. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...Small Craft Advisory from 11 PM Wednesday to noon EDT Friday for LMZ043-046. && $$ SYNOPSIS...MCD SHORT TERM...MCD LONG TERM...MCD AVIATION...Lashley Visit us at www.weather.gov/iwx Follow us on Facebook...Twitter...and YouTube at: www.facebook.com/NWSNorthernIndiana www.twitter.com/nwsiwx www.youtube.com/NWSNorthernIndiana