textproduct: Jackson

KEY MESSAGES

- Multiple rounds of showers and storms are expected today and tonight. A Slight Risk (Level 2/5) for severe storms with a damaging wind and a brief tornado risk covers western parts of the area for this afternoon and evening.

- Torrential downpours today and tonight 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 from Sunday through Tuesday.

- Somewhat drier and warmer weather returns Wednesday through Friday.

UPDATE

Issued at 725 AM EDT SAT AUG 1 2026

No significant changes were made to the forecast with mainly just the inclusion of the latest obs and trends for the T/Td/Sky grids as the steadier showers and embedded thunderstorms creep slower to the area. These minor adjustments have been sent to the NDFD and web servers along with a freshening of the zones.

LONG TERM

(Sunday night through Friday) Issued at 540 AM EDT SAT AUG 1 2026

The first part of the extended will be dealing with the de- evolution of that too early synoptic low slowly working east through and eventually out of the eastern Ohio Valley. This will keep low clouds and some rain around well into the start of the new work week - continuing the heavy rain concerns - though a more diurnal pattern takes over with time for the convection.

The previous long term discussion follows:

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 12Z TAFS through 12Z Sunday morning) ISSUED AT 755 AM EDT SAT AUG 1 2026

TAF period is starting off VFR with mainly a mid-level deck of clouds over the area. A surface low pressure and upper level low will bring in multiple rounds of convection. The first round of substantive convection will push into eastern Kentucky over the next few hours. Given this, opted to go with some rain showers from west to east across the TAF sites and did keep a prob30 for lowering vis and cigs with some potential for thunderstorms. There may be some slight improvements in cigs and vis for a period of time in the late morning and early afternoon hours, before another round of thunderstorm activity affects the area. Again this could bring in at least MVFR vis and cigs at times, but keeping this prob30 right now due to the fair amount of uncertainty with the overall convective trends. The winds will remain light and variable to start the period. However, expect winds to increase out of the south through the day, with some gusts of 15 to 20 knots possible this afternoon. These gusts could be higher if TAF sites are impacted by thunderstorm activity.

JKL WATCHES/WARNINGS/ADVISORIES

None.