textproduct: Jackson

KEY MESSAGES

- Very warm and mainly dry weather will persist through Tuesday afternoon.

- Showers and thunderstorms enter the forecast late Tuesday into Tuesday night, then persist through next weekend.

- The switch to a wetter pattern yields temperatures closer to normal readings and produces a highly-beneficial, widespread wetting rainfall.

UPDATE

Issued at 953 AM EDT MON MAY 18 2026

An upper level ridge was centered near the Outer Banks of NC and extended northwest into the Appalachians and Lower OH Valley. This is resulting in most sunny to sunny skies and warm temperatures for the second half of May. Another mild day is in store with highs averaging 10 to 15 degrees above normal. The record highs at KJKL of 88 (1982/1996) and for KLOZ of 90 (1962) will be approached and perhaps one or both tied today.

UPDATE Issued at 659 AM EDT MON MAY 18 2026

Made minor T/Td hourly updates in the very near term to reflect latest observations and latest trends.

LONG TERM

(Tuesday night through Sunday) Issued at 249 AM EDT MON MAY 18 2026

The long term forecast period opens on the precipice of a pattern change. A series of shortwave disturbances moving around the northwestern periphery of the previous days' amplified SE CONUS ridging will gradually work to break this ridge down. As this happens, flow in the lower half of the column adopts a more southwesterly orientation. This translates to increased moisture return and increasing sky cover into Tuesday night.

A frontal boundary arrives from the northwest on Tuesday night, and its forcing should be sufficient to spark additional showers and storms. The question is - how does the thermodynamic environment look ahead of this feature? Given the boundary's nocturnal arrival in our portion of the Commonwealth, temperatures and instability *should* be at their diurnal cycle minimum. However, the persistence of SW low level flow and the antecedent warmth will leave Tuesday night's surface temperature insulated well above climatological averages. Expect lows to remain above the 60 degree mark, with some of the warmer ridgetops potentially hovering around 70. Depending on the amount of sky cover present around sunset, valley locales could thermally decouple and experience efficient radiational cooling. This could yield a scenario in which upstream convection becomes elevated above a more stable boundary layer in the valleys once it reaches our CWA's western escarpment. In other words, we are on QLCS graveyard watch for Tuesday night into Wednesday morning.

Regardless of the strength of this convection, it will provide some highly beneficial widespread rainfall to eastern Kentucky. There is a 65-75% chance for at least a quarter of an inch of rain in the 24 hour period ending at 8pm Wednesday across the entire forecast area. The greatest chances and the greatest storm total QPF will fall across the Cumberland River Basin, which is also subsequently where some of the most impactful drought is also in place in the state - so any precipitation will be well received. While the boundary has trended a little bit more progressive with this morning's forecast guidance suite and storm total QPF has ticked a bit down, the boundary will struggle to fully push into the ridging in the SE CONUS. It is poised to stall out in the Tennessee Valley by midweek, and thus the southern half of the commonwealth will see repeated rain chances through the end of the period. Given these trends, Wednesday's Marginal (Level 1/4) Excessive Rainfall Outlook was trimmed down to just the Lake Cumberland region with the afternoon update. The entire Cumberland River Basin remains outlooked in a Marginal ERO for Thursday, as that boundary looks quite stubborn. Widespread, significant flash flooding is still not the most likely forecast solution, but areas where multiple rounds of thunderstorms persist for multiple days will need to be monitored closely as the ground progressively saturates. Again, this will likely be more beneficial than anything for the rain deficit in this region.

On the north side of the boundary, post-frontal winds will work to advect a cooler and drier airmass into portions of the area. Northern portions of the forecast area should cool into the upper 70s on Wednesday, and more recent guidance suggests that Wednesday's MaxT grids could actually trend downward in future forecast packages. Temperatures then cool to the 70s area-wide on Thursday. Unfortunately this reset back to cooler weather is short-lived. The same boundary that stalled to our south will then lift back north as a warm front on Friday, leaving much of eastern KY in the warm and unstable sector through the weekend as another surface low passes across the Ohio Valley. In addition to more warm air advection, it will also advect moisture into the region, resulting in heightened rain chances from Friday through Sunday. This second, potentially more active pattern bears watching for agricultural and hydrological interests, though. The LREF Grand Ensemble resolves a 70-90% chance of at least 1 inch of precipitation across the entire CWA by Saturday night, with more expected on Sunday.

AVIATION

(For the 12Z TAFS through 12Z Tuesday morning) ISSUED AT 701 AM EDT MON MAY 18 2026

VFR conditions will hold through the period. Southwest winds at 6 to 12 kts sustained develop between 13z-16z, with max gusts reaching as high as around 20 kts in the afternoon during peak heating for northern/western sites, before diminishing significantly at all sites toward sunset. Some models develop marginal south-southwesterly LLWS again briefly in the mid to late evening, but with low confidence, and with it appearing to be very transitory if it does occur, will opt to leave this out of TAFs for now.

JKL WATCHES/WARNINGS/ADVISORIES

None.