KLMK issues Area Forecast Discussion (AFD) valid 2019-12-01T17:43:00Z 005 FXUS63 KLMK 011743 AFDLMK Area Forecast Discussion National Weather Service Louisville KY 1243 PM EST Sun Dec 1 2019 ...Updated Aviation Discussion... .Forecast Update... Updated at 1118 AM EST Sun Dec 1 2019 ...Light Snow Accumulations Tonight Into Monday... The cold front has pushed through the area and temps will be steadily falling from this point forward. Gusty W winds have accompanied the frontal passage, with a lot of peak gusts in the upper 30 mph range. Had a couple of gusts over 40 mph at FFT/LEX, but overall will stick with the SPS has clouds are moving in and should keep most gusts mitigated more around the 35 mph range through the afternoon. Will be focusing on a challenging overnight forecast into Monday as some light snow accumulations are on the table. The biggest question with this forecast will be how much, if any, impact we will see? Surface temps are expected to remain at or just above freezing for the duration of precipitation into Monday. However, steeper low level lapse rates and periods of good saturation up through at least a portion of the DGZ could allow for some brief higher rates in some snow showers. Hi-res models seem to be behind this idea with spotty higher accums. Will these rates be high enough to overcome the surface/road temp limitations? It's going to be a tough call, and will likely be a situation where we see only spotty and brief notable accumulations. Will be discussing whether the current Special Weather Statement, or an upgrade to a Winter Weather Advisory for part of the area will be needed. If we did need an advisory, it would likely be mainly across our NE, E, and SE sections of the CWA. && .Short Term...(Today and tonight) Issued at 255 AM EST Sun Dec 1 2019 One final band of showery precip is showing up along the sfc boundary, which is nearing Interstate 65. As these showers make their way eastward across the area in the pre-dawn hours, it should be progressive enough to preclude any additional flood concerns. Therefore will allow the Flash Flood Watch to expire on schedule at 08Z. Mid-level dry slot should be established across the area by daybreak, with gusty west winds for much of the day. Think we'll have a hard time realizing Advisory criteria as the cloud cover will keep things from mixing too deep. However, will issue a Special Weather Statement for what should be fairly frequent 30-35 mph gusts. By late afternoon the upper low will be near Fort Wayne and we'll see more of a NW component to the flow aloft, allowing light rain showers to break out, especially across southern Indiana and north central Kentucky. Actually looks like we will keep enough moisture in place as temps cool through the night to allow a changeover to snow. Low-level lapse rates are steep enough for some convective character, but sfc temps are a little warm and saturation of the dendritic layer isn't quite there, so accumulations will be limited. Best chance for any accumulation will be 06-12Z Mon, and while anywhere will be fair game for up to a half inch, there's an outside chance for a few spots over toward the I-75 corridor to approach 1 inch. Should be just warm enough to limit impacts, but this bears watching in the next forecast cycle. .Long Term...(Monday through Saturday) Issued at 315 AM EST Sun Dec 1 2019 Monday... The core of the closed upper low will have moved over the Appalachians and Upper Ohio Valley by 12z Monday. Cyclonic flow aloft continues through Monday, but we lose all the mid-level moisture after 12z. Thick low clouds are likely to linger through the day, however. Column saturation is below the DGZ, but likely cold enough for continued light snow showers and flurries in the morning. Scattered light precip, including light snow showers and drizzle, looks possible mainly east of I-65. Temperatures will struggle with overcast skies and cold NW flow, so highs are only forecast to reach the mid to upper 30s. And with a very slow climb during the daytime and low WBZ heights, would not be surprised if flurries are the dominant p-type. Locations near the I-75 corridor could see a quick dusting Mon morning on top of the Sunday night precip. Monday night - Saturday... NW flow pattern flattens out through the middle of the week, so we'll see quiet and cool weather Mon night through Thursday. An upper wave passes overhead Tue night, but will be too moisture starved for any precip. A fast-moving southern stream system will scoot across the Deep South on Friday. Any impacts will be determined by its ability to phase with the northern stream, so will just hold onto low chance POPs for Friday. && .Aviation...(18Z TAF Issuance) Issued at 1244 PM EST Sun Dec 1 2019 A cold front has pushed through the area and we will see sustained winds between 15 and 25 mph, gusting up around 30-35 mph for the remainder of the afternoon and evening. Stratocu associated with the comma head of a large storm system to our north has wrapped back into the area, and we'll see deteriorating ceilings from W to E later this afternoon into the evening. MVFR and into the fuel- alternate range will be the most prevailing ceiling through the end of this cycle, however there is a chance of IFR ceilings at HNB/SDF/LEX after sunset and at time through the pre-dawn hours. LEX will hold onto IFR ceilings into Monday morning. The other issue is with light rain showers changing to some rain/snow mix or even brief light to moderate snow showers overnight. Confidence in changeover timing is low due to sporadic rate changes driving p-type, but overall only brief vis reductions and minor accumulations (<1") mainly on grassy and elevated surfaces are expected. && .Hydrology... Issued at 330 AM EST Sun Dec 1 2019 ...Minor River Flooding Ongoing... Area rivers are on the rise after widespread rainfall amounts of 1.5- 4 inches over the past 24 hours. Several river flood warnings are in effect for locations that are either already experiencing minor flooding or are forecast to rise to minor flood stage. Minor flooding is currently occurring along the Green River above Woodbury, Rough River near Dundee, Stoner Creek at Paris, and Elkhorn Creek at Peaks Mill. Additional minor flooding will likely occur early this week at other locations along the Green and Rolling Fork rivers. The Kentucky River will likely exceed Action stage and approach Flood Stage in a few locations, but confidence is slightly lower in Minor Flooding. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && $$ Update...BJS Short Term...RAS Long Term...EBW Aviation...BJS Hydrology...EBW