textproduct: Jackson

KEY MESSAGES

- Showers and thunderstorms will affect many locations into tonight, but will mostly taper off during the night. Dry weather then lasts at least until near the finish of the weekend

- Some thunderstorms may bring locally heavy rainfall into tonight, especially in south central and southeast Kentucky. - Somewhat less humid air will arrive behind a cold front tonight and allow for cooler morning lows through the weekend.

UPDATE

Issued at 807 PM EDT THU JUN 18 2026

Have updated for a cooler start to the evening and a faster tapering of precip in our northwest counties.

LONG TERM

(Saturday through Thursday) Issued at 627 PM EDT THU JUN 18 2026

The long term period will open with broad 500 mb troughing over the Northeastern CONUS and Midwest, with ridging over the Mountain West and High Plains. Farther west, a secondary, more compact trough will be located over the Pacific Coast. At the surface, high pressure will persist over Kentucky, and pleasant weather is expected throughout the day on Saturday. Highs will remain relatively mild (in the upper 70s to low 80s in most of the forecast area), and winds are expected to remain light, with good model consensus regarding a weak pressure gradient over our area. Some model discrepancy still exists regarding the exact location of this surface high during the day on Saturday, owing to differences in the eastward progression of this feature. This positioning will have implications on the magnitude of moisture return; a quicker eastward translation of this high would allow for enhanced moisture advection via southwesterly winds on Saturday, whereas a slower surface high would delay this moisture return. Regardless, skies should remain mostly clear on Saturday night into early Sunday morning, and with high pressure overhead, a modest ridge-valley temperature split is expected, with the floor for low temperatures remaining dependent on dewpoints going into Saturday night. MOS guidance suggests that low temperatures could fall into the mid 50s in our sheltered hollows, but given uncertainty regarding dewpoints going into the overnight hours, these hollows were generally kept in the upper 50s for now, with ridges seeing minTs in the low to mid 60s. This will also allow for typical fog formation overnight in mainstem river valleys.

On Sunday, a shortwave rotating around the base of the broad eastern CONUS trough will travel across the Plains, taking on a negative tilt as it approaches the Ohio Valley by Sunday evening. Meanwhile, the associated surface low will translate northeastward into the Midwest, and a warm front extending from this low is expected to lift northward into our area on Sunday as high pressure fully exits our area. Accordingly, rain chances are expected to return as early as Sunday afternoon. Instability will be modest Sunday evening (with mean ensemble CAPE well below 1000 J/kg across the forecast area), but will be adequate for some thunderstorms in our area. More notably, rich moisture is expected to be in place late Sunday into Monday, with anomalously high PWATs likely; LREF guidance shows mean PW values ranging from 1.7 to 1.9 inches across eastern Kentucky, indicating column moisture generally in the 95th percentile or higher compared to climatology. Accordingly, WPC has placed eastern Kentucky in a Day 4 and Day 5 Marginal Risk for Excessive Rainfall (Level 1/4), indicating an environment conducive to flash flooding on both Sunday and Monday. However, great uncertainty still remains with this pattern.

Rain chances will continue through at least Monday, although guidance diverges significantly at this point. Generally, multiple shortwaves could impact the area, leading to repeated shower and storm chances through at least Monday; after this, uncertainty compounds. At the surface, the original low is expected to generally continue to translate eastward along with an associated cold front, although there is presently low confidence regarding the progression of this front. Some models (such as the GFS) hint that the front may stall near our area, bringing repeated rounds of rain and storms to the Commonwealth. In this scenario, the flooding risk would increase, particularly given such rich preexisting moisture. Alternatively, other models (such as the ECMWF) favor a relatively progressive system, with the cold front clearing our area Monday night. With this discrepancy in mind, the spread for instability is quite large on Monday afternoon/evening; in a more progressive scenario, a combination of frontal forcing and relatively higher instability could allow for a low end risk for severe weather, with some machine learning guidance hinting at this possibility. However, uncertainty remains very high with this setup. Looking beyond Monday, confidence remains low as sensible weather impacts will remain dependent on the progression of embedded shortwaves within general troughing.

AVIATION

(For the 00Z TAFS through 00Z Friday evening) ISSUED AT 807 PM EDT THU JUN 18 2026

Showers and thunderstorms were affecting portions of the area at the start of the period, mainly south of a line from KSME-KJKL- KSJS. They were bringing localized IFR or worse conditions. Away from the precipitation, conditions were largely VFR. During the course of the night, a cold front will move southeast through the area and with it the remainder of the precipitation will taper off from northwest to southeast. Even though rain will diminish, the moist ground and decreasing clouds will favor eventual fog/low cloud development. Cooler and drier air arriving behind the front will fight against fog/low cloud development, but probably not prevent it. This leaves uncertainty to the extent. Any fog or low clouds should dissipate on Friday morning and leave VFR conditions to finish the period.

JKL WATCHES/WARNINGS/ADVISORIES

Flood Watch until 2 AM EDT Friday for KYZ058>060-068-069-079-080- 083>088-104-106>120.