@ FXUS63 KJKL 200545 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 145 AM EDT Wed May 20 2026 .KEY MESSAGES... - Shower and thunderstorms will become more prevalent today, with rain chances continuing through the upcoming holiday weekend. - The switch to an active and wetter pattern yields temperatures closer to normal readings, and is likely to provide at least temporary relief from developing and ongoing drought conditions. && .UPDATE... Issued at 1123 PM EDT TUE MAY 19 2026 The main change to the forecast was to lower overnight PoPs in our western and northern counties; this better reflects radar trends given a lull in showers and storms. Temperatures and dewpoints were also nudged to better fit current observations. Otherwise, the forecast remains on track at this time. UPDATE Issued at 707 PM EDT TUE MAY 19 2026 Given ongoing convection located primarily in Whitley and Laurel counties, the main change to the forecast at this time was to increase hourly PoPs for the southwestern portion of our forecast area. Convective coverage is still expected to diminish around sunset with the loss of daytime heating. Other than that, temperatures and dewpoints were nudged and winds were adjusted to be more in line with current observations. && .SHORT TERM...(This evening through Wednesday night) Issued at 400 PM EDT TUE MAY 19 2026 One more hot and mostly sunny afternoon is underway across eastern Kentucky. Satellite imagery shows an extensive cumulus field across the area and radar shows some spotty convection near and west of the Pottsville Escarpment. Thermometers are also near record territory for this date, ranging in the mid 80s for most. The latest weather map shows the high pressure responsible for the hot and dry weather of recent days now departing off the East Coast, though still dominating over the southeast US. Meanwhile, an ~1004 mb surface low is situated northeast of Lake Superior while a cold front extends southward from the low across the Ozarks and Southern Plains. Aloft, an around 588 dam ridge remains over much of the Southeast CONUS. Upstream, a 500 hPa trough is passing through Central Canada and brushing the northern Plains while a trailing shortwave is situated over the Great Basin. Vorticity energy is streaming northeastward from the Western Gulf area and across the mid-Mississippi and Lower Ohio Valleys in the southwest flow between these troughs and the Southeastern ridge. The northern stream trough will flatten and lift into eastern Canada through the short-term period along with the remnant Great Basin shortwave trailing as the ridging only slowly subsides over the Southeast CONUS. Meanwhile, the surface low will lift northeast toward Labrador while deepening ~990 mb. The low's trailing cold front will only slowly cross the Lower Ohio River late tonight and sag across eastern Kentucky during the day on Wednesday. Initially, upper level vort energy ejecting northeast from the Western Gulf coast should aid in the development of diurnally- driven scattered showers and thunderstorms through this evening, primarily near and west of the Pottsville Escarpment though an isolated shower or storm cannot be ruled out further east. Renewed convective activity may impact locations near and north of I-64 Wednesday morning predawn as the boundary approaches our area. Ahead of this boundary, the 19/12z HREF shows 1000 to 1500 J/kg of SBCAPE building by afternoon with 20 to 30 kts of surface-500 hPa shear south of I-64 by Wednesday midday to afternoon. This may be sufficient for some cell organization, especially for convection that develops discretely or in clusters out ahead of the cold frontal boundary. SPC has included most of the area under a Marginal Risk for severe weather on Wednesday for an isolated hail or damaging wind threat. Cloud layer winds will tend to force cells that develop along the actual cold front to move back atop a more stable post-frontal environment, limiting overall extent and vigor of convection along the true surface boundary. While PWATs ahead of the boundary will rise to near or over 1.50 inches, progressive cell movement and dry antecedent conditions (Moderate to Extreme Drought) should preclude any notable hydro concerns outside any urban/poor drainage areas that get a quick inch or two of rain under the heaviest activity. For Wednesday night, shower activity, mainly light, is likely to linger as disturbances aloft continue to drift over the forecast area. In sensible terms, spotty shower and thunderstorm activity will continue through mid-evening, diminishing after sunset. Showers may develop again toward morning, especially near and north of I-64 and closer to central Kentucky. Temperatures will be mild with lows in the lower to middle 60s. Additional shower and thunderstorm activity is expected to spread in from the northwest on Wednesday with highs ranging in the upper 70s northwest of I-64 to the upper 80s in the deepest valleys near the KY-VA border. Showers linger Wednesday night while temperatures settle back into the lower 50s north of I-64 to the mid 60s near the KY- TN border. .LONG TERM...(Thursday through Tuesday) Issued at 330 PM EDT TUE MAY 19 2026 The forecast period begins with the region situated on the backside of a departing cold front. Although the boundary will be sagging southward, scattered showers and thunderstorms remain possible across the area. Given marginal instability and weak kinematic profiles, severe weather is not anticipated, and activity should remain largely garden-variety. Ongoing precipitation and cloud cover will suppress daytime heating, keeping afternoon highs on the cooler side. Temperatures are forecast to reach the lower 70s across the northern portions of the area, while areas along the Tennessee border should top out in the upper 70s. Overnight lows for Thursday into Friday morning will remain mild as a quasi-stationary boundary begins to lift northward as a warm front, initiating a warming trend. This warm front will cross the region on Friday, serving as the catalyst for widespread showers and thunderstorms throughout the day. While marginal thermodynamic indices will once again favor pulse-type, non-severe convection, the primary hazard shifts toward heavy rainfall and high precipitation efficiency. This wet pattern will persist through the weekend as precipitable water values climb well above 1.50 inches within a deep moisture profile characterized by a skinny CAPE distribution. Furthermore, ECMWF Shift of Tails (SoT) values are progged to approach 0.8 on Friday before exceeding 0.8 Sunday into Monday. For context, a SoT greater than 0.8 is highly indicative of an unusual event relative to the climatological norm. As Fridays synoptic evolution locks the region into a pattern supportive of repeated training rounds of convection, this event may ultimately be classified as climatologically anomalous. An analysis of the GEFS and ECMWF ensemble systems reveals strong model consensus, with nearly all Total QPF members indicating that rainfall totals upwards of 3.00 inches are possible through Monday morning. The current deterministic forecast package projects widespread QPF amounts ranging from 2.00 inches in the Lake Cumberland area to 2.75 inches across northeastern portions of the forecast area. Locations along the West Virginia and Virginia borders will likely see lower totals due to local downsloping effects. Once the stalled boundary finally shifts eastward on Monday, another surface low is progged to develop and track northeastward into the area. This system will bring a secondary round of showers and storms, keeping the region wet through the remainder of the forecast period. As a side note, since the area is dry, heavy rainfall on top of moisture starved ground could create runoff issues leading to potential hydrologic issues. Ultimately, this period will highlight a distinct regime shift away from the persistent dry pattern observed over the last few weeks toward a much wetter synoptic setup. While the expected heavy rainfall will help reduce the current precipitation deficit, overall totals will still track below normal for this time of year. Due to persistent cloud cover and rain, daytime highs will remain capped in the upper 70s to lower 80s, while overnight lows drop into the lower to middle 60s. && .AVIATION...(For the 06Z TAFS through 06Z Thursday) ISSUED AT 143 AM EDT WED MAY 20 2026 Valley fog has developed in and around locations that saw rain during the afternoon and evening Tuesday, including at least briefly at KSME and KLOZ. This fog may continue intermittently through 09z-12z this morning, or until increasing lower cloud cover provides sufficient insolation to dissipate fog. Otherwise, the forecast features widespread VFR gradually diminishing to sub-VFR conditions as shower and thunderstorm activity increases through the morning and afternoon, with activity become more showery in nature after about 23z-02z, as the instability is mostly tapped out by that time as a weak cold front stalls from near KSJS to KJKL to north of KSME around 00z Thursday. Widespread MVFR or lower conditions are then likely after 00z as the front remains across the area and shower activity continues through the end of the TAF period. Thunderstorm activity will be most prevalent in the afternoon period, and a few storms could be on the strong side with gusty winds and hail. && .JKL WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...FAGAN/JP SHORT TERM...GEERTSON LONG TERM...VORST AVIATION...CMC