textproduct: Topeka

KEY MESSAGES

- A Heat Advisory is now in effect through Saturday evening with heat indices of around 100 to 106 degrees each afternoon.

- Additional advisory days beyond Saturday remain possible.

- A few showers are possible over north central Kansas this morning. Otherwise dry into the weekend.

- The pattern finally changes late next week with the first real rain chances and near normal temperatures.

DISCUSSION

Issued at 217 AM CDT Thu Sep 3 2026

The 00Z RAOB data show the H5 ridge holding over the southern and central Plains with weak flow directly overhead and southwest flow displaced over the Intermountain West into the northern Rockies. The Pacific Northwest trough and associated upper low remain the primary features of consequence upstream, with tropical moisture remaining along the Gulf coast. At the surface, a quasi-stationary boundary sits north of the area in Nebraska with lee troughing to the west, mainly over central into western Kansas. The entire CWA remains under the heat dome once again today. On Wednesday, heat indices touched the 103 to 106 range around midday before deep mixing scoured afternoon dewpoints into the low 60s, trimming heat indices back toward the air temperature by late afternoon. The NBM continues to run both too cool on highs and too moist on afternoon dewpoints. This has been taken into account for this forecast cycle as well.

Early this morning, weak ascent along the 305 K isentropic surface over north central Kansas may squeeze out a few showers. Forecast soundings keep a deep dry layer below cloud bases, so anything that falls fights sub-cloud evaporation and coverage stays isolated at best. Chances hold below 15 percent and end by mid morning, with most locations staying dry and any measurable rainfall confined to a few spots.

The heat headline driver remains focused on the dewpoint question and the depth of adiabatic mixing, and the HREF ensemble members suggest this as well. Thursday afternoon dewpoint spread at Topeka runs from near 60 in the drier members to near 70 in the moister ones, and that range is the difference between heat indices near 100 and heat indices in the middle 100s. The drier solutions have verified each afternoon by mid afternoon, though not before heat indices reached advisory criteria around midday, and that midday window is what the Heat Advisory now in effect through Saturday evening covers. Beyond Saturday, southerly flow persists and the ensemble mean keeps afternoon dewpoints in the middle 60s with H85 temperatures holding in the middle 20s C, so Sunday and Labor Day sit on the advisory fence as well. If the deeper mixing keeps verifying, criteria likely remain marginal; if the moistening trend wins, an extension through the full weekend will likely win out. Either way the heat itself is slow to recede: highs in the upper 90s to near 100, warmest north central where mixing depths are deepest, with overnight lows in the middle and upper 70s keeping record warm minimums in play through Saturday morning.

The ridge holds through the holiday weekend and into early next week. Ensemble data suggest the mid level heights over the area stay elevated with tight member agreement through Tuesday, and WPC cluster analysis keeps positive height anomalies over the central US in every cluster into the middle of next week. Slight rain chances along the Nebraska border early next week most likely reflect the growing spread rather than an organized signal. The real change appears to arrive late next week. Ensemble heights fall sharply around Thursday as the Pacific trough finally ejects into the Plains, H85 temperatures step down several degrees C at the same time, and the cluster favoring that evolution is weighted toward the ECMWF membership. That system may bring the first meaningful rain chances in two weeks and the first stretch of near normal temperatures since around the third week of August. Confidence in the pattern change is increasing slightly based on the most recent trends; confidence in the exact day remains low.

AVIATION /12Z TAFS THROUGH 12Z FRIDAY/

Issued at 547 AM CDT Thu Sep 3 2026

VFR conditions through the period with a persistent forecast in place once again. Shortly after sunrise, expect the LLJ to begin mixing partially to the surface with wind and wind gusts increasing to the mid 20kt range this morning into the afternoon before relaxing again this evening.

CLIMATE

Issued at 212 AM CDT Wed Sep 2 2026

Record highest minimum temperature information:

Record Forecast

September 4 Topeka 78, set in 2014 74 Concordia 79, set in 1954 75

September 5 Topeka 76, set in 1983 75 Concordia 78, set in 1899 76

TOP WATCHES/WARNINGS/ADVISORIES

Heat Advisory until 9 PM CDT Saturday for KSZ008-KSZ009-KSZ010- KSZ011-KSZ012-KSZ020-KSZ021-KSZ022-KSZ023-KSZ024-KSZ026-KSZ034- KSZ035-KSZ036-KSZ037-KSZ038-KSZ039-KSZ040-KSZ054-KSZ055-KSZ056- KSZ058-KSZ059.