166 FXUS63 KLMK 190001 AFDLMK Area Forecast Discussion National Weather Service Louisville KY 801 PM EDT Wed Mar 18 2020 .Mesoscale Update... Issued at 801 PM EDT Wed Mar 18 2020 One last band of light to moderate showers will continue pushing east across the area over the next few hours. The severe weather threat appears very low. The moderate showers will be mainly concentrated in a band moving east across southern KY, but wind gust potential even there has diminished. Very poor low level lapse rates with building CIN have significantly reduced the wind potential. DCAPE is also very low at around 200 J/kg. && .Short Term...(This evening through Thursday) Issued at 340 PM EDT Wed Mar 18 2020 Very conditional SVR threat remains in play for south central Kentucky, as the warm front is trying to push north out of Middle Tennessee. Hi-res progs try to increase sfc-based CAPE up the I-75 corridor, but if the rain shield gets there first the strong storm potential diminishes substantially. Mid-level wave should quickly exit the region tonight, providing a break in the widespread rain. Another vigorous wave ejects out onto the Central Plains Thursday, and will lift a warm front northward across the area by early afternoon. Steep mid-level lapse rates will support a hail threat along the warm front. We'll break solidly into the warm sector in the afternoon and could actually see a break in the action, especially over south central Kentucky. Likely or even categorical POPs will persist along and north of I-64, while temps punch well into the 70s farther south. .Long Term...(Thursday night through Wednesday) Issued at 300 PM EDT Wed Mar 18 2020 Thursday Night through Friday...Closed 5H low over the Central Plains will be nearly vertically stacked with its surface low by Thursday night and will continue to deepen and advance to the NE past the Great Lakes and into Quebec by Friday night. Any lull in showers and storms will likely be short lived Thursday evening before the Ohio Valley becomes positioned within the right entrance region of a 85kt mid-level jet with a broad low-level jetting of 55- 60kt, which will likely result in an uptick in convective activity overnight and into Friday morning. Thermodynamic and kinematic profiles continue to support the chance of severe weather overnight with MUCAPE values around 500 J/kg and bulk shear values ranging from 45 to 60kts between 20/00Z to 20/06Z. Low LCLs and high values of effective SRH and 0-3km CAPE also suggest the potential for an isolated tornado exists. Overall, the main hazards will be damaging winds, but all other hazards including hail, tornadoes, lightning and localized flooding are all on the table. Locations with the best potential for severe weather will be in our counties west of I-65, which has been highlighted in the most recent Day 2 Outlook from SPC. Tight gradient ahead of and behind the cold front will also result in gusty surface winds in the 25-30mph range. Strong SW flow will also result in above normal temps with Friday morning lows in the 60s and afternoon highs in the low 70s. As mentioned previously, river flooding and localized flash flooding is possible as total accumulation through Friday ranges between 1.25 to 2.50 inches. Saturday through Sunday...High pressure descends out of Canada bringing colder temperatures to the Ohio Valley over the weekend. Residual cloud cover Saturday morning will help to keep morning mins in the 30s, but we'll gradually see clearing skies throughout the day with afternoon highs topping off in the upper 40s to lower 50s. Mostly clear to partly cloudy skies overnight into Sunday morning will allow for radiational cooling with mins dipping into the upper 20s to lower 30s. Will continue to monitor for any needed Frost/Freeze headlines as we enter into the weekend. Sunday night and beyond...The next chance of rain will come Sunday night through Monday as another shortwave ejects out of the eastern Pacific trough, but most of this energy looks to pass to our south. Another impulse is set to quickly follow with more rain and thunderstorm chances arriving Tuesday. Return flow will bring a warming trend back to the region beginning Monday. && .Aviation...(00Z TAF Issuance) Issued at 749 PM EDT Wed Mar 18 2020 Light to moderate showers will continue moving east across the area between 00-06z, with a lull in precip expected late this evening into the overnight period. The lowest ceilings in the IFR to Fuel Alternate range are generally over southern Indiana and portions of central KY north of a BWG to LEX line. Ceilings are expected to deteriorate to IFR and even LIFR tonight. Expect IFR vsbys at times as well with the LIFR stratus. It looks like BWG could be spared the lowest conditions along with the rest of far southern KY, but expect significant restrictions further north. Yet another storm system in the Plains will pull a warm front north across the area Thursday morning. BWG or SDF and areas to the west have the best chance at seeing prevailing showers and storms with this front. HNB has the best chance for widespread showers/storms around 14-16z. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && $$ Mesoscale...EBW Short Term...RAS Long Term...CG Aviation...EBW