Area Forecast Discussion

KEY MESSAGES

- Dry conditions with warmer than normal days and nights will continue through the work week.

- Chances of showers return to the region this weekend, with the best chances Saturday late evening into Sunday.

- A subsequent system is projected to arrive early to midweek next week, with some potential for heavy rain and/or thunderstorms.

DISCUSSION

Issued at 228 AM CDT Wed Oct 28 2026

Upper level ridging over the Quad State will slightly break to our northwest as a disturbance moves from Kansas City towards Chicago. Rainfall tracks well northwest of the Quad State. With large surface high pressure to our east, a familiar pattern from the last several days is projected for today and tomorrow: dry conditions, above normal temperatures, light winds, and localized patchy morning fog.

Thursday night, a trailing cold front extending from a Canadian system may brush the northern portions of the Quad State. Precipitation is not expected, nor is any notable drop in temperatures. As we move into the weekend, the remnants of Tropical Storm Vance are projected to track northeastward through Texas. There remains some model variation in timing and positioning, but PoPs Saturday into Saturday evening have decreased some as models are dialing in focus a little bit later. Can't rule out rain interfering with Halloween activities quite yet, with evening PoPs of 30-40% in SEMO (though, considering these are 6 hr PoPs, early evening chances would be a bit lower). A negatively tilted shortwave trough moves through Sunday morning, accompanying some of the better precip chances with the weekend system. Overall QPF is still limited with amounts maxing out near an inch in the Southern Pennyrile, but PWs near 200% of normal can put higher amounts in play. NBM 48hr QPF probs hold at 30% chance of an inch or more in West Kentucky and 5-10% of two inches. Convective potential has shifted down again, with thunder removed from the blend. With the arrival of this system, and afterwards, highs drop from around 80 to closer to 70, though lows remain well above normal in the 50s.

Two systems arrive at the West Coast over the weekend, with low pressure dropping southeastward to the Pacific Northwest, and another system moving east-northeastward into Southern California. Split flow merges over the Rockies and develops into a large system in the Plains, though perhaps not as extensive a spiral as the deterministic GFS. A steady stream of moisture pulls from the Gulf into the system, and an amplifying pattern with ridges over the Rockies and east coast can stall out the system over the Plains through midweek. Ensemble mean 48hr rainfall over the Quad State with this system is 1-1.5", while the deterministic is higher. Some portions of the Plains/Mississippi River Valley could receive several inches of rain, but it remains to be seen whether the Quad State will end up in the rainier zone. After all, multiple primary components of this system are days from the West Coast.

AVIATION /00Z TAFS THROUGH 00Z THURSDAY/

Issued at 1051 PM CDT Tue Oct 27 2026

High clouds will gradually push east tonight, leaving behind mainly clear skies. Conditions will be favorable for shallow ground fog to develop again with calm winds in place. The most impactful fog (MVFR or lower restrictions) will be at the climatologically-favored terminals (CGI and MVN). South winds develop tomorrow morning, picking up between 4-6 kts by late morning into the afternoon.

PAH WATCHES / WARNINGS / ADVISORIES

IL...None. MO...None. IN...None. KY...None.