textproduct: Topeka

KEY MESSAGES

- Scattered showers taper off today. Then mostly dry through Monday night.

- Still expecting several rounds of rain Tuesday through Thursday, with the heaviest rain likely late Wednesday into Thursday. Widespread 1-3" totals, along with locally higher amounts that could lead to flooding.

- Mild temperatures persist. Highs stay near average, lows above average.

DISCUSSION

Issued at 330 AM CDT Sun Sep 27 2026

Water vapor imagery this morning shows a weak, elongated trough axis over the eastern Plains. This feature is becoming sheared out, stuck between a building ridge over the High Plains and the deep upper low fueling the nor'easter off the Mid-Atlantic coast. We still have some scattered showers across the area this morning in the vicinity of the trough axis. These showers should gradually taper off throughout the day, as upper ridging expands eastward and a weak inverted surface trough also shifts southeast of the area. Can't rule out a brief sprinkle overnight and into tomorrow as easterly low- level flow keeps some shallow moisture around, but for the most part upper ridging should keep us dry through Monday night. With continued easterly flow and at least broken cloud cover, highs today and tomorrow look to stay generally in the mid/upper 70s.

The focus of the forecast continues to be on heavy rain potential Tuesday into Thursday. A deep upper low will strengthen over the Southwest early this week, picking up Hurricane Polo and bringing its remnants northeast. Even without the hurricane remnants, the path of the strong upper low would be favorable for deep moisture transport from the south. Guidance continues to indicate a prolonged period of PWAT approaching 2", supportive of very heavy rain when combined with strong synoptic ascent. The main question is where the better synoptic ascent will end up. Current guidance is hinting that the heavier rain may come in two semi-distinct rounds. The first of these looks to be Tuesday into early Wednesday, more associated with the remnants of Polo as it lifts north-northeast over western TX and KS. The heaviest rain (an axis of 2-5") with this round is trending slightly farther northwest, closer to the main surface low. However it still looks close enough to bring moderate to heavy rain (perhaps 1-3") to portions of the area, particularly towards central KS.

The second round then quickly follows later Wednesday into Thursday night with the main upper low. This looks like the best potential to bring heavy rain to the entire forecast area, particularly with a southeastward moving cold front providing additional forcing for ascent. Potential rain totals across the week haven't changed much. High confidence in over 1", with LREF 1" probabilities over 90 percent area-wide. Ensemble mean QPF in the 2-2.5" range seems reasonable for a most-likely amount, while 90th percentiles still suggest some areas may see 4-6". Given high dewpoints and persistent cloud cover, expecting warm overnight lows and cool daytime highs to continue through Thursday. By Friday into Saturday, precipitation chances drop off as we see drier and slightly cooler air move in behind the front.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

Issued at 606 AM CDT Sun Sep 27 2026

Can't rule out a brief shower either this morning or this evening, but expecting dry conditions to prevail overall. Similarly, ceilings should stay predominantly VFR, but we could see some scattered MVFR ceilings develop this morning or (less likely) again late tonight. Winds stay light and from the east.

TOP WATCHES/WARNINGS/ADVISORIES

None.