367 FXUS63 KJKL 030619 AAA AFDJKL AREA FORECAST DISCUSSION...UPDATED National Weather Service Jackson KY 119 AM EST Fri Dec 3 2021 .UPDATE... Issued at 119 AM EST FRI DEC 3 2021 Did make a few adjustments to the temperatures based on the trend in the observations. Ridges will likely remain mixed a bit longer through the overnight, so have bumped up readings for these locations. Some valley sites have already dipped into the 30s, so will leave most of the lows at the typically colder locations intact. Updates will be out shortly. UPDATE Issued at 1155 PM EST THU DEC 2 2021 Just a quick update to the grids mainly to add in the latest obs and trends to the Sky/T/Td ones. Also tweaked low temperatures a tad for more terrain distinction as well as to include some fog mainly along the rivers. These adjusted grids have been sent to the NDFD and web servers. UPDATE Issued at 815 PM EST THU DEC 2 2021 00Z sfc analysis shows high pressure building into eastern Kentucky as low pressure retreats to the east. This is helping to relax the pressure gradient whose southwesterly winds helped give us such a pleasant and dry day - though the drying, winds, and lower RH likely contributed to some wildfires per satellite. As such, temperatures made it into the low 70s in many places but have since fallen to the mid 60s on the ridges and mid to upper 50s in the valleys. Meanwhile, dewpoints are rather dry in the mid 30s to lower 40s most places amid slackening southwest winds generally from 5 to 10 mph now with some gusts to near 20 mph still happening. Just some high clouds are drifting by aloft but these will likely not hinder the development of good radiational cooling through the night resulting in a significant ridge to valley temperature difference. Have updated the forecast to mainly include the latest obs and trends for the T/Td grids. These updates have been sent to the NDFD and web servers. && .SHORT TERM...(This evening through Friday night) Issued at 332 PM EST THU DEC 2 2021 The afternoon surface analysis shows High pressure in the Gulf of Mexico and low pressure to the north in Canada. We do have a pressure gradient in play this afternoon and this in conjunction with a 850mb response to a 300mb jet streak moving across the Ohio Valley is giving way to gusty winds this afternoon. This is also advecting above normal temperatures with a few spots working into the 70s this afternoon. These winds will decrease through the late afternoon and evening as the left exit region of this jet streak pushes east. These windy and dry conditions have led to a few fire noticeable on various GOES-16 channels, but this should relent through the evening and tonight and winds slacken. Tonight we will see mostly clear and calm conditions in most cases. However, do see some indications in the forecast soundings that suggests the potential for some fog or perhaps low stratus late tonight into Friday morning. For now did add in some valley fog, but was a little more uncertain on how extensive the stratus would be given the very dry air in place. Therefore will leave this idea out for now, but something that will need to be assessed in future updates. Also given the mostly clear and calm conditions would be expected for many locations at least some ridge/valley splits would be possible, with lows in the low to mid 30s in some of the deeper valleys. For this went closer to the tenth percentile of the NBM to capture this idea. Friday will be a split in terms of temperatures with mid to upper 60s in the southwest and northeast looking at highs in the low to mid 60s. This mainly due to some better southwest flow in the southwest and perhaps a few more clouds not out of the question late in the day in the northeast. Otherwise overall another above normal day in terms of temperature for most location. More low and mid clouds remain possible Saturday night and this would lead to a lesser chance of ridge/valley splits, but still added in a degree or two difference in the deeper eastern valleys. .LONG TERM...(Saturday through Thursday) Issued at 455 PM EST THU DEC 2 2021 The period begins Saturday with more quasi-zonal flow aloft, though the pattern quickly becomes more amplified moving forward thanks to a shortwave moving in from western Canada. This wave continues to deepen through the weekend as it travels over the Plains, with deeper troughing eventually over the Ohio Valley by Monday. A large associated surface low crosses the Great Lakes region before traveling northeast into eastern Canada Monday, dragging along a cold front through the region. The cold front is currently expected to start moving into eastern Kentucky roughly around the 12z time frame Monday, eventually exiting the state roughly between 18z and 21z with an area of high pressure quickly moving in behind it. Agreement through this earlier portion of the forecast is decent, leading to a fair amount of forecast confidence. However, model agreement begins to deteriorate heading towards the middle of the week. Models are having a rougher time handling the evolution of another upper level wave descending from the Pacific Northwest, and its potential interactions with a southern stream wave near Baja California and eventually the Lower Mississippi Valley. Regarding sensible weather, we start the period off Saturday with dry conditions. Skies will be partly cloudy, mainly in the southern half of the CWA, and temperatures will be cooler than earlier in the weekend thanks to a frontal boundary making its final push south. Highs range from the mid to upper 50s, though this is still warmer than normal for highs for early December. Sunday, as the previously mentioned frontal boundary gets lifted north as a warm front and we get stronger return flow, temperatures once again climb well into the 60s after beginning that morning in the mid 30s to low 40s. The stronger cold front will bring widespread rain to east Kentucky Sunday night, though showers are possible earlier during Sunday afternoon and evening as deeper moisture is brought up into the region. Forecast soundings show some small amounts of CAPE in portions of our far southwest (west of the I-75 corridor), suggesting that some thunder could be possible in that region. However, chances are meager and mention of thunder has been left out for now, though this will continue to be evaluated as this time frame approaches. Rain will eventually come to an end from west to east through Monday morning into the afternoon. After a brief dry period Monday night through early Tuesday thanks to transient high pressure, unsettled weather returns by late Tuesday. Though there is confidence in the occurrence of precipitation overall during the latter portion of the extended, the abundant model disagreement and large ensemble spread leads to low confidence in any more specific details. Temperatures past the weekend overall trend towards more seasonal norms, though are subject to the same uncertainty as the rest of the forecast Monday and beyond. && .AVIATION...(For the 06Z TAFS through 06Z Friday night) ISSUED AT 119 AM EST FRI DEC 3 2021 VFR conditions will dominate through the majority of the period, with variable winds of around 5 kts or less. Some patchy fog will be possible towards dawn within the deeper river valleys, but this is not expected to impact the TAf sites. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GEOGERIAN SHORT TERM...DJ LONG TERM...HAS AVIATION...GEOGERIAN