432 FXUS63 KLMK 260528 AFDLMK Area Forecast Discussion National Weather Service Louisville KY 128 AM EDT Sun Apr 26 2020 ...Updated Aviation Discussion... .Forecast Update... Issued at 600 PM EDT Sat Apr 25 2020 Sfc low is just south of Evansville, with an occluding front arcing east and then SE, just west of Bowling Green but just north and east of Nashville. A fairly solid rain shield covers southern Indiana and much of central Kentucky, keeping a lid on SVR potential. There is a small dry slot near Lake Cumberland, and it will have a very limited opportunity to destabilize ahead of any convection along the occluded front. So we can't rule out a strong storm or two down that way, but that window is closing and the more favorable environment for storms to rotate is solidly in TN per latest SPC mesoanalysis. Expect an update shortly to better convey the precip trends, which may involve carrying the categorical POP into the evening for more of the area. Over the next hour or so we expect to tone down our messaging as the severe threat diminishes. && .Short Term...(This evening through Sunday) Issued at 315 PM EDT Sat Apr 25 2020 18Z surface analysis reveals an area of low pressure near Mt. Vernon IL with a warm front extending southeastward through parts of western Kentucky. Just ahead of this low pressure system, convection has fired across west-central KY in the Pennyrile region. This area saw a bit of clearing and insolation earlier this afternoon which allowed temps to surge well into the upper 60s. Current mesoanalysis showed a bubble of instability from Hopkinsville northward to Owensboro where 750-900 J/Kg of CAPE was available and this area was coincident with moderately steep lapse rates of around 7-7.4 C/KM. The storms have been pulsing up and down producing up to 1 inch hail. Latest high resolution guidance suggests that this convection may organize into a short segment line and lift northeast, posing a threat of near severe hail, heavy rainfall, lightning, and gusty winds across Hancock, western Breckinridge, and Perry county IN over the next hour or so. Instability does wane a bit to the north and east of the current convection where earlier cloud cover has limited heating and near surface instability. Further south and east, mainly across the karst region, ongoing cloud cover and convective debris has thus far limited instability across the region. Convection has developed across west-central TN as expected and should continue to move northeastward this afternoon. While shear profiles remain favorable for severe convection, aforementioned concerns about instability results in lower certainty to severe potential. Latest HRRR guidance continues to show the potential for stronger storm development across southern KY this afternoon. Overall, thinking is that we'll see widespread rain showers, with isolated to scattered stronger storms developing. Highest threat of severe weather still looks to remain south of a line from roughly Bowling Green over to Jackson and points south. Strongest storms would be capable of hail and damaging winds. However, shear profiles are strong enough that an isolated tornado can't be ruled out. Convection should continue to move eastward and diminish in intensity this evening as the surface low moves through central Kentucky. Widespread rain showers will continue on the backside of the system this evening and will persist into the overnight hours. Lows tonight look to drop into the upper 40s. For Sunday, widespread cloudiness will continue with scattered to numerous rain showers continuing across the region. The shower activity looks to diminish in coverage by late afternoon, perhaps lingering into the evening in the east. Highs on the day will likely range from the lower 50s over across the Bluegrass region and the I-75 corridor, with middle middle 50s across the I-65 corridor. Some partial clearing could take place across the far west by afternoon which may allow temps to warm into the upper 50s. .Long Term...(Sunday night through Saturday) Issued at 245 PM EDT Sat Apr 25 2020 By Sunday evening the upper level trough axis will lie over the spine of the Appalachians with the surface low out east over the Garden State. Any remaining light rain should shut off around midnight in our eastern counties as wrap around moisture exits in the area. Low amplitude ridging aloft and associated surface high pressure will usher in drier air presenting the OH Valley with a pleasant Monday with morning temps in the high 30s. Could see a patchy fog scenario in the AM hours if clouds roll out early enough during the night to allow for sufficient radiational cooling. Otherwise, mostly sunny skies and light winds will see max temps rise into the mid 60s. By Tuesday a shortwave ejecting SE out of Canada will undergo lee- side cyclogenesis forming a closed low aloft and bringing showers and thunderstorms back to southern Indiana and central Kentucky from Tuesday through Thursday. Warm sector air ahead of the cold front and a modest LLJ will allow for a chance of showers through the day on Tuesday. Showers become more widespread Tuesday night and throughout the day Wednesday as the cold front sweeps through the region. Best chance of storms will likely be Wednesday afternoon into early evening with the aid of actual frontal lifting. The low center is progged to track across the Lower Great Lakes, which could place our area in a more favorable environment for potential severe weather, though dew points at this time are only expected to reach into the mid 50s with highs in the upper 60s. Will keep an eye on this system as newer data becomes available. By Wednesday evening, the vertically stacked low will begin moving east with wrap around moisture prolonging cloud cover and light rain chances through Thursday morning. Removed any mention of thunderstorms on Thursday as model soundings show a strong subsidence inversion at around 850mb capping any deep convective potential. Therefore, expect to see dry conditions for the latter half of Thursday with the exception of any pop up diurnal showers. Friday also looks to be dry as high pressure returns to the region. NW flow aloft will allow for subtle impulses to ride along the northern stream that could bring rain shower chances back to the area on Saturday. && .Aviation...(06Z TAF Issuance) Issued at 128 AM EDT Sun Apr 26 2020 Sfc low pressure has progressed eastward over northern KY, now located just south of CVG. Waves of showers and low level moisture continue to pinwheel around the low and will continue to stream across central KY and southern IN through the afternoon hours. Currently seeing a mix of IFR and MVFR ceilings with SDF and BWG right around the 1 kft threshold. Ceilings are expected to deteriorate a bit over the next 1-2 hours, with clouds remaining socked in at IFR/Fuel Alternate levels through mid to late morning. Confidence in IFR is high at LEX and BWG, but HNB and SDF will be more marginal with several hours of Fuel Alternate ceilings possible before clouds finally lift to VFR by late afternoon/early evening. Winds will continue to veer out of the west behind the low and then the northwest during the mid-morning hours. Expect breezy NW winds through a lot of the morning and afternoon hours with occasional gusts to 25 kts. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && $$ Update...RAS Short Term...MJ Long Term....CG Aviation...EBW