textproduct: Jackson

KEY MESSAGES

- The potential for showers and thunderstorms will persist through Monday.

- Some of the storms could arrive as organized clusters with a possibility for strong to damaging wind gusts. - Excessive rainfall may occur where storms are most persistent, or train, leading to flash flooding.

- Heat indices will flirt with Heat Advisory levels (~105F) through early this evening.

UPDATE

Issued at 821 PM EDT SUN AUG 16 2026

Convection, some of it severe has blown up over the northern part of the area this evening, and the POP has been raised to accommodate it. Persistent or training cells have largely been outside our area so far, but problems could arise shortly and it will be monitored.

LONG TERM

(Tuesday through Sunday) Issued at 353 PM EDT SUN AUG 16 2026

At the onset of the long term period, a strong closed upper level low will sit over Manitoba, with general troughing over the northern CONUS, especially in the vicinity of the Great Lakes. Meanwhile, a relatively flattened ridge will linger over the southern US, with eastern Kentucky finding itself in a region of zonal to slightly northwesterly flow aloft, depending on the orientation of ridging. At the surface, the previous frontal system will be south of the forecast area, having fully moved through, and surface high pressure will be building near the Middle Mississippi Valley. Behind the surface high, a secondary cold front associated with the relatively vertically stacked Canadian low will extend southward into the Upper Midwest. As these features travel eastward, building high pressure over the forecast area will keep eastern Kentucky largely dry on Tuesday. Temperatures will be fairly seasonable as well, with highs ranging from the mid to upper 80s across the forecast area. Clear skies overnight may allow a very modest ridge/valley temperature split to develop, with the limiting factor being lingering moisture. MOS guidance is rather aggressive with these splits, but given expected moisture, valley minTs have been nudged down only modestly into the low 60s for now. Of note, fog formation on Wednesday morning appears likely for much of the forecast area, particularly in typical mainstem river valleys.

Dry weather will persist through much of Wednesday as surface high pressure continues to translate through the area. Meanwhile, the upper level trough will continue to dig towards the Commonwealth, with the aforementioned cold front pushing southeast. By Wednesday evening, the front will approach eastern Kentucky and rain chances will return to the area. Of note, some models depict an additional shortwave traversing the base of the trough (roughly centered over the Ohio Valley) around the time frontally forced convection approaches, or perhaps slightly before. This enhanced mid level flow may elevate shear somewhat, and depending on frontal timing, instability may also be adequate for stronger storms, although model spread remains quite high at this time. Any risk for severe weather (or lack thereof) remains dependent on how these ingredients line up, with overall risk looking quite low at this time. Meanwhile, a moist air mass will be in place ahead of the front, with LREF mean PW values generally in the range of 1.6-1.7 in (roughly 80th percentile or higher compared to climatology). This, in addition to potentially enhanced convective coverage if shortwave energy interacts with the front, could allow for at least isolated instances of flash flooding. Again, model variability remains very high at this stage, but WPC has already outlined the forecast area in a Day 4 Marginal (Level 1/4) Risk for Excessive Rainfall on Wednesday, and an additional Day 5 Marginal Risk on Thursday as the system sags south. Guidance does suggest the front will slow as it passes through the southern portion of our area and into Tennessee. Exactly how quickly this boundary progresses is still a source of uncertainty, but rain chances have been maintained through Thursday to account for this slowing motion. Any hydrological concerns will also be dependent on the speed of this frontal passage in addition to the extent of convective coverage.

Following the frontal passage, troughing will continue to amplify, eventually digging all the way into the Southeast as ridging retreats towards the Four Corners region. This will usher in cooler weather, with high temperatures as low as the upper 70s for some locations on Friday (and perhaps lower if convection can take hold). Additional impulses will keep at least scattered showers and storms in the forecast each day, with rain chances generally peaking in the afternoon/evening.

AVIATION

(For the 00Z TAFS through 00Z Monday evening) ISSUED AT 821 PM EDT SUN AUG 16 2026

Thunderstorms are ongoing over the northern portion of the forecast area, and sinking south. They will probably affect all but the southern TAF sites with IFR or worse conditions at times this evening. After this evening's storms, it leaves considerable uncertainty as to how things play out overnight into Monday morning. Earlier, it appeared that the greater threat of storms would be later in the night or Monday morning, but it is unclear how current activity will impact that potential. Have used generalized PROB30 groups in TAFs over an extended period. Fog hasn't been hit very hard in the forecast, but it may need to be reconsidered in the wake of current precip.

JKL WATCHES/WARNINGS/ADVISORIES

None.