textproduct: Jackson

KEY MESSAGES

- Multiple rounds of showers and storms are expected Saturday into Saturday night. A Slight Risk (Level 2/5) for severe storms with a damaging wind and a brief tornado risk covers areas over and west of I-75 and the Bluegrass late Saturday.

- Torrential downpours Saturday and Saturday night could result in isolated flash flooding, especially across the western two- thirds of the area.

- A slow-moving system keeps daily shower and storm chances, along with some heavy rain potential, in the forecast Sunday through Tuesday.

- Drier and warmer weather returns Wednesday through Friday.

LONG TERM

(Sunday through Friday) Issued at 411 PM EDT FRI JUL 31 2026

The long-term period dawns Sunday morning with a weak, closed ~575 dam low spinning over southwest Indiana within a positively- tilted trough that extends northeastward toward James Bay, where a broader 500 hPa trough is pivoting across eastern Canada. This upper-level low will lie nearly vertically stacked atop an occluding ~1004 mb surface low. While that does not sound all that impressive, the NAEFS and ECMWF ENS show that MSLP values of this depth fall below 1979-2009 CFSR climatology, indicative of how rare it is to have a developed mid-latitude cyclone passing through the Ohio Valley this time of year. The system's cold front will extend from the eastern side of the low near Cincinnati, southward along the I-75 corridor into Tennessee, and then southward into the Lower Mississippi Valley.

While guidance still shows the northern stream 500 hPa trough pivoting across Eastern Canada and adjacent portions of the Great Lakes and Northeast later Sunday and Sunday night and stealing some of the energy from the southern stream trough/ closing low, the 31/12z model suite seems to be latching onto more of the vorticity energy remaining with the closed low and gyrating over the Ohio Valley and Central Appalachians on Monday and Tuesday. That system only slowly departs later in the week on Wednesday and Thursday as broad upper-level troughing develops over the North Central to Northeast CONUS, and an associated belt of westerlies aloft captures the remnant low and sweeps it away. Flow over the Ohio Valley trends quasi-zonal by late week.

At the surface, the low pressure system over the lower Ohio Valley remains nearly vertically stacked as it drifts to over the Mid- Ohio Valley on Monday, where it wobbles and largely dissipates before its remnants are pulled away to the north by mid-week. As a result, the system's cold front will slowly cross the JKL CWA during the day on Sunday. Within the warm sector, some of the longest-range CAMs are hinting at the possibility of enough shear and instability for at least weakly organized convection ahead of the cold front again on Sunday afternoon, especially closer to VA and WV. With the upper-level low lingering aloft, PWATs are now likely to stay elevated through the day on Sunday, as well as Monday and Tuesday (more so than what was expected in recent days). The result will be a lot more cloud cover and diurnally- modulated convection with greatest rainfall coverage during the afternoon and evening and continued though lower rain chances at night. The combination of a lingering nearly saturated deep warm cloud layer, skinny CAPE profiles, and elevated PWATs in the 1.75 to 2.00 inch range, warranted the addition of Marginal Risk EROs for both Monday and Tuesday. The threat for heavy rainfall subsides later in the week as the upper-level low departs and increasingly zonal flow allows drier and warmer air to filter eastward from the Plains mid-week. While a few pop-up thunderstorms will be possible from Thursday through Saturday, activity should remain more isolated to perhaps scattered and be confined largely to the afternoon and evening hours.

In sensible weather terms, look for a relative lull in the rainfall Sunday morning, giving way to more widespread shower and thunderstorm activity during the afternoon. Some of the convection could be strong with gusty winds and torrential downpours. It will be humid and mild with highs mainly in the lower 80s. Rain chances will then follow a diurnal cycle on Monday and Tuesday, with coverage greater during the afternoon and evening but still remaining possible at night. It will be quite humid and muggy with afternoon highs mainly in the lower 80s and nighttime lows in the mid to upper 60s. The pattern turns drier from Wednesday onward with more sunshine and daily high temperatures warming into the mid to perhaps upper 80s, while nighttime lows range from 65 to 70F.

AVIATION

(For the 18Z TAFS through 18Z Saturday afternoon) ISSUED AT 229 PM EDT FRI JUL 31 2026

A scattered mid level CU field was observed across northern TAF sites this afternoon as well as higher level cirrus working in from the west. VFR conditions look to continue through much of the TAF period, but increasing clouds are expected with the approaching low this evening. -SHRA was introduced to all TAF sites anytime after 10-12Z Saturday morning, with thunderstorm probabilities gradually increasing from 13Z onward. Winds will be light and variable through much of the TAF period, becoming light and southerly anytime after 12Z Saturday. Any storms that do pass over TAF locations can drop conditions from VFR into MVFR or IFR conditions.

JKL WATCHES/WARNINGS/ADVISORIES

None.