735 FXUS63 KLMK 110503 AFDLMK Area Forecast Discussion National Weather Service Louisville KY 103 AM EDT Thu Oct 11 2018 ...Updated Aviation Discussion... .Forecast Update... Issued at 830 PM EDT Wed Oct 10 2018 Pre-frontal trough focus for light to moderate rains and a few embedded thunderstorms this evening, mainly east of the I-65 corridor. Had a couple of thin lines up stream try to form, but they are not having much success. Hi-res models are more focused on filling in a line over the eastern half of the region the next few hours, and seeing continues showers from OHX to FFT as well as shield of precip encroaching from central TN, this forecast is reasonable. Have trended towards that in a forecast update. The actual cold front should show up in the KHNB over the next hour or two...then get into the BWG/SDF line around Midnight EDT and then over to LEX between 2 and 4 AM. On a climate note, SDF is in line to tie its warm min record for this date, unless the temperature drops below 71 by Midnight EST (or 1 AM EDT). LEX does look to breaks it record for the date, which is 67. Their low so far today has been 70. BWG is in line for a tie as well, but given they have to wait till Midnight CST (or 2 AM EDT), it seems more likely they will fall below the 70 degrees they've had so far today. && .Short Term...(This evening through Thursday) Issued at 315 PM EDT Wed Oct 10 2018 The strong cold front extending from the ~1000 mb upper Midwest surface low is currently along and just west of the Mississippi River. It can be seen on latest visible satellite imagery and surface analysis steadily progressing eastward, and will arrive later tonight. Ahead of this feature, some breaks in the clouds along with a steady warm advection component has allowed for some meager but notable destabilization. Temps in the upper 70s/low 80s combined with dew points in the upper 60s to near 70 is creating around 500-1000 J/KG of CAPE across SW and W portions of our CWA. From a shear standpoint, seeing around 25-35 knots of 0-6 km shear beneath the right entrance region of an upper jet. Expect to see a bit of enhancement later this evening as a 500 mb wave rides up the Ohio Valley to the point where deep shear in that area could get closer to 40 knots. By this point, think the best instability will be waning by then. Already starting to see some development across our western CWA and this should increase in coverage and intensity along a pre-frontal trough and ahead of better forcing with the aforementioned shortwave. This should quickly move across our area between now and 03z, with little activity back along the front shortly after. Given the lack of instability and marginal deep layer shear think the threat for strong storms is still low. Nevertheless, a short window later this afternoon and evening could exist for some brief bowing segments/isolated wind threat with any organized shower/storm. 0-3 km shear vector do try to become more perpendicular to storm motion the later into the evening we get, but we also lose magnitude as this occurs. Overall, pretty marginal setup and not very concerned. Precipitation should shut off pretty quickly from west to east, with some showers possibly lingering in our far east around dawn. High pressure tries to build in quickly tomorrow with sunny skies and cool temperatures prevailing. Temps fall off in the overnight with lows likely in the upper 40s NW to upper 50s E by Thursday morning. Highs Friday should only reach the low to mid 60s given gusty cold advection. .Long Term...(Thursday night through Wednesday) Issued at 320 PM EDT Wed Oct 10 2018 Thursday Night through Saturday Night... High pressure is forecast to continue to build into the region Thursday night and into Friday. However, a sharp upper trough axis is forecast to swing through the region Friday afternoon/Friday night which will bring a round of light rain showers to the region. These showers may linger into early Saturday before another period of dry weather pushes back into the area for Saturday and into Saturday night. Lows Thursday night and Friday morning may drop into the upper 30s across southern Indiana and parts of far western/northwestern KY. This may produce some patchy frost in those areas. There also could be some light frost across the far northern sections of the Bluegrass region as temperatures settle into the 38-41 degree range. Highs on Friday will be some 10 degrees below normal with highs in the upper 50s across southern IN and the northern half of KY. Lower 60s look to be limited to the southern third of Kentucky. The aforementioned upper level system coming in Friday afternoon/eve will likely bring more cloudiness to the region resulting in milder readings for Friday night. Lows look to cool back into the upper 30s across southern IN with mainly 40-45 across much of Kentucky. Saturday will again be cool with highs in low 50s across the northern Bluegrass with mid-upper 50s elsewhere. Lows Saturday night look to drop back into the upper 30s again in southern IN with Kentucky seeing lows in the 38-43 degree range. Sunday through Wednesday... In the extended period, the global models still exhibit quite a bit of spread in handling the next weather system streaming through the US. Aloft, a broad west-southwest flow will be seen across the US. An advancing upper trough and associated surface front are forecast to push into the region early in the period. The GFS remains the most progressive with the remnants of Pacific tropical cyclone Sergio swing through the region on Sunday. The Canadian and Euro are much slower with the system allowing it to pass through about 18- 24 hours later on Monday. For now, have blended the global models which results in a basic update to the previous forecast. In general, unsettled weather looks to the main weather story for the Ohio Valley from Sunday through early Tuesday. From late Tuesday and beyond, drier and continued cool weather is expected. Highs on Sunday look to warm into mid-upper 50s across southern IN and much of KY. Southern KY may stay briefly warm with lower 60s. Monday through Wednesday should feature highs mainly in the mid- upper 50s and overnight lows in the upper 30s to the lower 40s. && .Aviation...(06Z TAF Issuance) Issued at 100 AM EDT Thu Oct 11 2018 A strong cold front is currently working through parts of central Kentucky and southern Indiana this morning. Winds behind the front have gusted over 20kts across southern IL this morning, and would expect those type of gusty winds in this region as well. Ceilings along and just behind the front are expected to drop into the fuel- alternate MVFR range for a couple of hours before gradually clearing out. A large swath of high-end MVFR ceilings across MO/IL are pushing toward the region, and could arrive over the next several hours if it holds together. Short term models have handled these clouds very poorly and have little to nothing in the way of cloud cover this morning, so confidence with this portion of the forecast is lower than normal. Drier air is forecast to arrive by the early afternoon, and should result in clear skies for the rest of the day. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && $$ Update...RJS Short Term...BJS Long Term...MJ Aviation...DM