362 FXUS63 KJKL 210742 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 342 AM EDT Tue May 21 2024 .KEY MESSAGES... - Dry weather is expected area wide through Wednesday morning. High temperatures may approach or exceed record levels this afternoon. - There is a potential for showers and thunderstorms at times from Wednesday afternoon through Monday. - Very warm temperatures will persist through Wednesday. An increase in clouds and the possibility of rain will bring somewhat lower temperature after that, especially Thursday and Friday. && .SHORT TERM...(Today through Wednesday) Issued at 340 AM EDT TUE MAY 21 2024 Warm advection increases through the short-term period as a strong cyclone grazes the Mid-Ohio Valley through early Wednesday evening. With the mid-level jet stream remaining west and northwest of the forecast area, however, shower and thunderstorm activity will remain limited. For today, near-record high temperatures in the mid- to upper 80s are expected as southerly flow begins to increase (yet remains light) near the surface and southwest flow increases aloft as upper ridging remains just to the southeast over the Southeast US. There appears to enough instability and moisture to justify PoPs of around 10 percent for this afternoon, not quite enough to warrant mention in the official forecasts (15 is required) for almost the entire forecast area. Heading into tonight, a southwesterly low-level jet will impact the Mississippi and Lower Ohio Valleys, including the Bluegrass region, just grazing our western and northwestern counties in the CWA. Therefore, warm and dry conditions are expected yet with increasing high clouds. Lows will generally be in the upper 50s to mid to upper 60s, coolest in the deeper valley locations. Lower atmospheric winds increase Wednesday morning around or just after daybreak ahead of am impinging cold front into the Midwest, well upstream of the forecast area. This will help to increase moisture and instability through the day, especially toward the Bluegrass region. Have thus kept slight chance to chance PoPs (15 to 40 PoPs) for much of northern through southwestern parts of the forecast area beginning in the afternoon and extending into the early evening hours. Warm temperatures continue despite the increasing warm advection and cloud cover with mid to upper 80s expected once again. .LONG TERM...(Wednesday through Monday) Issued at 522 PM EDT MON MAY 20 2024 There is decent enough agreement with respect to the pattern aloft among the operational models through Dy5, Saturday, then solutions diverge from there with some of the more significant synoptic features. Pattern is best described as being a broad zonal flow across the eastern CONUS. Further west a few lows rotate in a circle the wagons fashion across the northern Rockies and Canada's BC with a mean trough stretching down to the Baja. On occasion, short wave energy shoots eastward from out of the mean trough sitting over the West Coast and Rockies. Main challenge is the timing and strength of each of the short wave disturbance as it tracks across the country and into the Ohio Valley, or Commonwealth, particularly after Dy5 where there is less agreement in solutions. At the surface, a weak frontal zone will sag southward across the region by Wednesday night, providing a focus for mainly afternoon and evening diurnal convection from late Wednesday through to the end of the forecast window as a series of disturbances travel through the region. Sensible weather generally features a warm and unsettled extended, with daily high temperatures ranging from around 80 into the mid 80s, approximately 5 degrees above normal on average. Thursday and Friday are our two coolest days with clouds and rain keeping temperatures around 80 for highs each day. With extra cloud cover overnight lows are expected to run generally in the 60s, though guidance suggests some mid to upper 50s will be possible if there is enough clearing that takes place on any given night. Should temps dip into the 50s, one could expect valley fog to be a good bet, similar to what we have experienced over the past week. Not seeing much in the way of obvious hazardous weather threats. There are periods of time where there is some marginal effective shear 30-35 kts to deal with. However, at this time not seeing any periods of time where ample instability matches up with the necessary shear for the more robust and/or organized convection. Overall this aspect of the forecast is of a lower confidence with respect to the potential of hazardous weather. Total rainfall expected through the period from late Wednesday through Monday is generally around 1.5 inches or less. The Weather Prediction Center does include portions of eastern Kentucky in a Marginal risk of excessive rainfall for Day 5, Friday. && .AVIATION...(For the 06Z TAFS through 06Z Tuesday night) ISSUED AT 340 AM EDT TUE MAY 21 2024 VFR conditions will continue to prevail through the majority of the period. The only exception will be some MVFR or lower fog that will occur in the river valleys between 06Z and 13z. The fog is expected to be more confined this morning compared to the past couple of mornings. KSME and perhaps KLOZ and KSJS have a chance to dip into the MVFR/IFR range at least briefly between about 06Z and 12Z, and thus included TEMPO groups for these locations. Winds will average around 5KT or less through 14Z, before becoming south to southwest at less than 10Kt to end the period. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CMC LONG TERM...RAY AVIATION...CMC