textproduct: Jackson

KEY MESSAGES

- Thunderstorms could produce locally heavy rainfall through this evening, with a potential for flash flooding.

- The current regime will persist through early in the new week, with shower/thunderstorms expected at times, with isolated to scattered instances of additional flooding being a concern.

- The potential for rain will wane at mid week and heat is forecast to build. Heat indices are forecast to top 100 in most places by late week.

UPDATE

Issued at 700 PM EDT FRI JUL 18 2025

With high PW persisting, and ongoing convection upstream as well as signals for heavy rain this evening in some CAMS and the 12Z HREF, opted to extend the Flood Watch for a few more hours through the evening into 1 AM EDT on Saturday.

The pattern over the weekend with high PW and a front stalled or nearly stalled over the OH Valley vicinity will be conducive for additional isolated to scattered flash flooding concerns and an extension into the weekend or a future flood watch for the weekend is likely to be needed.

LONG TERM

(Sunday through Friday) Issued at 253 PM EDT FRI JUL 18 2025

The mean upper-level synoptic pattern indicates upper-level troughing to the northeast of the region, with a 590 dam ridge positioned over the Gulf Coast. The forecast area is situated between these two features for much of the forecast period. A stationary boundary, a remnant of a stalled cold front from the weekend, is forecast to be oriented west to east across the Commonwealth, which will contribute to increased shower and thunderstorm activity through the day Sunday. Widespread severe weather is not anticipated due to a lack of significant deep-layer shear necessary for sustaining organized thunderstorms. However, forecast precipitable water amounts continue to run above climatological norms, and tall, skinny CAPE soundings indicate that precipitation on Sunday could be efficient, leading to continued hydrological concerns. Showers and storms are forecast to dissipate toward sunset, leading to a quiet night with river valley fog development.

Monday will feature conditions similar to Sunday; however, forecast soundings indicate a trend toward a drier atmospheric column, with PW values decreasing to approximately 1.40 to 1.60. While this suggests a drier airmass aloft, the potential for heavy rainfall continues to exist. As with Sunday, showers and storms will dissipate in the late evening, giving way to overnight areas of valley fog.

Upper-level height rises begin to propagate into the area for Tuesday, leading to warmer temperatures. However, dew points are forecast to decrease as streamlines indicate overland flow, resulting in a drier airmass. This will work to limit the overall convective potential; nonetheless, the potential for showers and storms will be none-zero and will persist through the afternoon into the early evening before dissipating overnight.

Height rises are forecast to increase for Wednesday and will remain prominent through the rest of the period, leading to the warmest temperatures of the forecast period. Rain chances will become isolated after Wednesday, but there are still slight chances of precipitation each afternoon through the remainder of the period.

Overall, the forecast period will be highlighted by periods of heavy rainfall beginning Sunday and continuing through Monday. PoP chances will begin to slowly decrease from Tuesday onward, but the threat of rain never entirely diminishes. High temperatures will start in the upper 80s but by Wednesday, these highs will climb into the mid to upper 90s. Overnight lows will follow a similar warming trend.

AVIATION

(For the 18Z TAFS through 18Z Saturday afternoon) ISSUED AT 134 PM EDT FRI JUL 18 2025

Showers/thunderstorms are again on the increase as heating builds instability. Will expect a mid-late afternoon peak, but some convection may last through the night and into Saturday before another uptick begins toward the end of the forecast period. IFR or worse conditions may occur in showers/thunderstorms. Otherwise, VFR conditions are forecast until tonight, when fog will begin to affect some locations (particularly valleys which received rainfall). Fog will again dry up on Saturday morning.

JKL WATCHES/WARNINGS/ADVISORIES

Flood Watch until 1 AM EDT Saturday for KYZ044-050>052-058>060- 068-069-079-080-084>088-104-106>120.