textproduct: Jackson

KEY MESSAGES

- Very warm and mainly dry weather will persist through this evening.

- Shower and thunderstorms will become more prevalent tonight and Wednesday, with rain chances continuing through the upcoming holiday weekend.

- The switch to an active and wetter pattern yields temperatures closer to normal readings, and is likely to provide at least temporary relief from developing and ongoing drought conditions.

UPDATE

Issued at 1123 PM EDT TUE MAY 19 2026

The main change to the forecast was to lower overnight PoPs in our western and northern counties; this better reflects radar trends given a lull in showers and storms. Temperatures and dewpoints were also nudged to better fit current observations. Otherwise, the forecast remains on track at this time.

UPDATE Issued at 707 PM EDT TUE MAY 19 2026

Given ongoing convection located primarily in Whitley and Laurel counties, the main change to the forecast at this time was to increase hourly PoPs for the southwestern portion of our forecast area. Convective coverage is still expected to diminish around sunset with the loss of daytime heating. Other than that, temperatures and dewpoints were nudged and winds were adjusted to be more in line with current observations.

LONG TERM

(Thursday through Tuesday) Issued at 330 PM EDT TUE MAY 19 2026

The forecast period begins with the region situated on the backside of a departing cold front. Although the boundary will be sagging southward, scattered showers and thunderstorms remain possible across the area. Given marginal instability and weak kinematic profiles, severe weather is not anticipated, and activity should remain largely garden-variety. Ongoing precipitation and cloud cover will suppress daytime heating, keeping afternoon highs on the cooler side. Temperatures are forecast to reach the lower 70s across the northern portions of the area, while areas along the Tennessee border should top out in the upper 70s. Overnight lows for Thursday into Friday morning will remain mild as a quasi-stationary boundary begins to lift northward as a warm front, initiating a warming trend.

This warm front will cross the region on Friday, serving as the catalyst for widespread showers and thunderstorms throughout the day. While marginal thermodynamic indices will once again favor pulse-type, non-severe convection, the primary hazard shifts toward heavy rainfall and high precipitation efficiency. This wet pattern will persist through the weekend as precipitable water values climb well above 1.50 inches within a deep moisture profile characterized by a skinny CAPE distribution. Furthermore, ECMWF Shift of Tails (SoT) values are progged to approach 0.8 on Friday before exceeding 0.8 Sunday into Monday. For context, a SoT greater than 0.8 is highly indicative of an unusual event relative to the climatological norm. As Fridays synoptic evolution locks the region into a pattern supportive of repeated training rounds of convection, this event may ultimately be classified as climatologically anomalous. An analysis of the GEFS and ECMWF ensemble systems reveals strong model consensus, with nearly all Total QPF members indicating that rainfall totals upwards of 3.00 inches are possible through Monday morning. The current deterministic forecast package projects widespread QPF amounts ranging from 2.00 inches in the Lake Cumberland area to 2.75 inches across northeastern portions of the forecast area. Locations along the West Virginia and Virginia borders will likely see lower totals due to local downsloping effects. Once the stalled boundary finally shifts eastward on Monday, another surface low is progged to develop and track northeastward into the area. This system will bring a secondary round of showers and storms, keeping the region wet through the remainder of the forecast period. As a side note, since the area is dry, heavy rainfall on top of moisture starved ground could create runoff issues leading to potential hydrologic issues.

Ultimately, this period will highlight a distinct regime shift away from the persistent dry pattern observed over the last few weeks toward a much wetter synoptic setup. While the expected heavy rainfall will help reduce the current precipitation deficit, overall totals will still track below normal for this time of year. Due to persistent cloud cover and rain, daytime highs will remain capped in the upper 70s to lower 80s, while overnight lows drop into the lower to middle 60s.

AVIATION

(For the 00Z TAFS through 00Z Wednesday evening) ISSUED AT 755 PM EDT TUE MAY 19 2026

Following current radar trends, PROB30 groups were added for KSYM and KIOB east of ongoing convection in Central KY, although this activity should generally diminish as it approaches after sunset. Between 04Z and 13Z, valley fog could bring visibility reductions to MVFR or lower, but this is not currently expected to impact TAF sites. A stray shower or storm cannot be ruled out overnight, but confidence remains low.

Tomorrow, generally by the 15z to 18Z timeframe, convection will become more widespread as a cold front approaches. PROB30 groups were added after 15Z or 16Z to account for thunder chances at TAF sites, with MVFR to IFR or lower reductions possible in strongest cells. The strongest storms could also produce localized gusts in excess of 30 kts.

JKL WATCHES/WARNINGS/ADVISORIES

None.