textproduct: Jackson

KEY MESSAGES

- A more significant cold front could produce multiple rounds of thunderstorms on Tuesday and Tuesday night. Those storms will be capable of severe weather and excessive rainfall.

UPDATE

Issued at 1107 PM EDT SUN JUL 19 2026

Satellite imagery reveals fog developing in valleys where rain occurred in the southern portion of the forecast area. There are some low clouds present. They appear chaotic and not dominant at this point, but it remains to be seen how things evolve. Have reduced forecast sky cover in the south in the very near term. Temperatures are slower to fall than was forecast (especially in our northeast), and minor adjustments have been made for this, but without altering the morning lows at this point.

UPDATE Issued at 903 PM EDT SUN JUL 19 2026

The last of the precip is almost gone, and will fade out shortly. The main question will become the timing and extent of fog development during the night. There is potential for a low cloud deck to affect mainly our southern counties overnight, which would affect fog potential. With light winds in a moist surface air mass beneath dry mid-upper levels, fog is favored should low clouds not inhibit it.

LONG TERM

(Tuesday through Sunday) Issued at 340 PM EDT SUN JUL 19 2026

The extended forecast period will start out active as Mondays warm front lifts north through the area, bringing an increase in shower activity overnight Monday into Tuesday morning. Along with the potential for early morning shower and thunderstorm activity, an MCS is forecast to track southeastward toward the CWA from the southern Great Lakes. The 18Z CAMs suite is starting to resolve this feature at the far end of the forecast cycle. Model soundings ahead of the approaching MCS depict a highly potent thermodynamic environment capable of supporting strong to severe thunderstorms, with damaging wind gusts serving as the primary threat.

The 12Z NAM forecast sounding reveals MLLCAPE values exceeding 2500 J/kg, effective bulk shear around 50 knots, and ESRH values near 175 m2/s2. Additionally, 0 to 3 km shear vectors of approximately 30 knots oriented orthogonal to the forecast UDCZ indicate that the MCS will propagate into an environment highly favorable for maintaining convective organization, where damaging wind signatures and brief spin-up tornadoes are possible. However, uncertainty remains due to meager low and mid-level lapse rates, which may act as a limiting factor for deeper updraft acceleration. As well as, the potential for ongoing shower and thunderstorm activity that could overwork the atmosphere and atmospheric recovery doesnt occur. Nonetheless, the area is under a SPC Day 3 Enhanced Risk for much of the area and areas not in the Enhanced area are in the Slight Risk category.

In addition to the severe weather risk, an elevated hydrologic threat is forecast to develop. The southern flank of the MCS is expected to become the focus for training thunderstorms. Deep moisture will be in place with forecast precipitable water (PW) values exceeding 2.00 inches. This exceptional moisture profile will support highly efficient rainfall rates over already saturated soils, increasing the risk for flash flooding. Furthermore, ensemble probabilities indicate that integrated water vapor transport will approach the 99th percentile of climatology. In collaboration with the Weather Prediction Center, the Day 3 Slight Risk Excess Rainfall Outlook has been expanded to encompass the entirety of the JKL CWA.

As the forecast MCS and the actual cold frontal squall line exit the area through the day Wednesday, surface high pressure will gradually build into the region. This will usher in a period of dry weather and slightly below seasonal temperatures through late Friday afternoon. Extended guidance then suggests that the next low pressure system will bring a return of shower and thunderstorm chances beginning late Friday evening and persisting through the remainder of the weekend.

The extended period opens with a high-impact weather setup as a potent MCS and cold frontal squall line moves into an unstable, highly sheared environment on Tuesday. This system brings a distinct threat of damaging winds, brief tornadoes, and flash flooding. A cold front cleans out the area Tuesday night, introducing a cooler and drier high-pressure regime from Wednesday through Friday afternoon before another storm system brings renewed rain chances for the weekend.

AVIATION

(For the 00Z TAFS through 00Z Monday evening) ISSUED AT 903 PM EDT SUN JUL 19 2026

The period has started with mainly VFR conditions. A few very isolated showers were still present, but will fade out this evening. Fog development is expected during the night, starting in valleys and then spreading, especially where rain occurred in the southern portion of the forecast area on Sunday afternoon. Currently, it is forecast to bring IFR conditions to KSME and KLOZ at least at times overnight and early Monday. Once the fog and any low clouds dissipate on Monday morning, VFR conditions should last through the remainder of the period.

JKL WATCHES/WARNINGS/ADVISORIES

None.