178 FXUS63 KLMK 011314 AFDLMK Area Forecast Discussion National Weather Service Louisville KY 814 AM EST Sun Jan 1 2023 ...Forecast Update... Issued at 805 AM EST Sun Jan 1 2023 Dense fog remains fairly widespread across most of the region at this hour, so decided to extend the Dense Fog Advisory another hour to 14z. Also expanded the headline northward to include the Indiana counties along the Ohio River after KJVY (Clarksville) has been reporting vis down to a quarter mile. Will continue to monitor trends in the coming hour and reassess the Advisory before the new expiration time. .Short Term (Today and tonight)... Issued at 250 AM EST Sun Jan 1 2023 This morning the main focus in the forecast will be areas of dense fog across the area, mainly through central KY. Observations as well as web and traffic cameras show dense fog with visibilities of a half to even a quarter of a mile. Will continue the Dense Fog Advisory for all of our KY counties until 13z. Model soundings as well as RH time-heights show a nearly saturated layer near the surface from about 900 increasing to 850mb later this afternoon with a dry air in the mid layers around 500mb. This will keep a low stratus deck over most of the area through the morning and into the early afternoon. Stalled boundary currently over northern TN is expected to slowly lift northward as a warm front. This will likely lead to some partial of the clouds south and along the Western Kentucky/Bluegrass Parkways towards the KY/TN border while areas to the north remain mainly cloudy. Temperatures where skies clear later today could warm into the the low/mid 60s while areas to the north will be in the upper 50s to just near 60. Warm front will continue to lift northward this evening and overnight as an increasing LLJ of 30-35kts approaches from the southwest. This will advect in very warm moist air over the area. Clouds will increase and temperatures will stay nearly steady overnight with temperatures dropping only into the low 50s. .Long Term (Monday through Saturday)... Issued at 215 AM EST Jan 1 2023 --------------------------------------------------------------------- Key Messages - Anomalously warm temperatures Monday and Tuesday. - Conditional threat of isolated strong/severe storms with heavy rain Monday night into Tuesday. - Gusty 30-40 mph southerly winds Monday Night - Tuesday. - Return to more seasonable temperatures late in the week. --------------------------------------------------------------------- By Monday morning, a compact upper level trough/low will begin ejecting into the central/southern Plains and lee cyclogenesis will commence shortly thereafter. A surface warm front associated with the deepening low will begin to lift northward into the Great Lakes region, encompassing southern Indiana and central Kentucky well within the warm sector. Southerly flow will pick up across our region with a tightening pressure gradient, though the real breezy/windy conditions will come Monday night into Tuesday (more on that later). Temperatures will warm up well into the 60s, though we'll likely stay below record highs for the day as widespread stratus will limit surface heating and boundary layer mixing. Will likely have a better chance of coming close to records Tuesday (see climate section of AFD for more details). The deepening surface low will push into the Midwest Monday night into Tuesday morning. Ahead of it, a strong LLJ will develop and funnel Gulf of Mexico moisture northward into the Tennessee and lower Ohio Valleys. Models prog at least one (but likely multiple) round(s) of showers and storms developing ahead of a pre-frontal trough to our south/west and eventually pushing into our region late Monday night or Tuesday morning. A low-end (but non-zero) areal threat for strong/severe storms is possible, though their severity is largely conditional on the availability of very meager instability. Model soundings generally show moist adiabatic profiles with little to no instability, and some (depending on the timing of convection) show a small surface inversion with ongoing convection. Overall confidence in severe potential is very low, given that small changes in surface stability and thermodynamic profiles could mean the difference between isolated strong/severe storms or elevated non- severe convection. Main hazard with any severe storm would be damaging wind gusts, though isolated spin-up tornadoes would be possible given high amounts of helicity in the lower atmosphere. A marginal threat for localized flooding is possible as well, given the environment will support heavy rain within storms. Confidence is higher in gusty gradient winds Monday night into Tuesday given extremely strong low/mid level winds. Some of the projected wind gust output from models show gusts 40 to 50 mph across the region during that timeframe, though a look at model soundings suggest that it may be a bit overdone given that a subtle/small inversion near the surface will keep the strongest winds from mixing down. Regardless, it will still be windy, and think 30-40mph southerly gusts would be more attainable. Cooler and drier air will filter in behind the front Tuesday night into Wednesday. A compact wave/vort lobe on the backside of the trough could bring very light precipitation to the region late Thursday into early Friday, and depending on temperature profiles, could have a wintry component to it. && .Aviation (12Z TAF Issuance) Issued at 630 AM EST Sun Jan 1 2023 Widespread dense fog continues this morning across most of the Ohio Valley. TAF Sites LEX/HNB/SDF were all reporting LIFR or VLIFR due to CIG and VIS. Expect the dense fog to continue through 14-15z before we start to see slow improvement. While VIS may improve later this morning, low LIFR to IFR CIG will remain between 500-1000ft through around 18z when we could see CIG lift enough to MVFR flight categories for SDF/LEX with HNB holding on to IFR. BWG has been a wild card this morning as it briefly improved to VFR then back to MVFR around 10-11z. Given upstream conditions and current satellite imagery, expect a return to at least IFR if not LIFR later this morning with possible period of dense fog at the start of the forecast period. As the sfc boundary lifts northward late this afternoon and evening, wouldn't be surprised if BWG/LEX/SDF was able to scattered the clouds out with improving flight categories to VFR working from south to north late this afternoon and into the evening. HNB looks to remain under the low stratus and range between IFR and MVFR through the day and into evening. && .Climate... Updated at 211 AM EST Sun Jan 1 2023 ================== Near-Record High Temperatures ================== Monday 1/2/2023 Tuesday 1/3/2023 (Fcst/Record) (Fcst/Record) Louisville: 67/72 (2006) 68/70 (1880) Bowling Green: 70/74 (2006) 70/71 (2004) Lexington: 66/67 (2006) 67/68 (2000) && .LMK WATCHES/WARNINGS/ADVISORIES... KY...Dense Fog Advisory until 9 AM EST /8 AM CST/ this morning for KYZ023>043-045>049-053>057-061>067-070>078-081-082. IN...Dense Fog Advisory until 9 AM EST /8 AM CST/ this morning for INZ084-089>092. && $$ Update.........CJP Short Term.....BTN Long Term......DM Aviation.......BTN Climate........DM