378 FXUS63 KTOP 140522 AFDTOPArea Forecast Discussion National Weather Service Topeka KS 1222 AM CDT Sun Sep 14 2025
.KEY MESSAGES...
- Shower and storm chances spread west to east Sunday. There could be a few strong storms across north central KS.
- Warm temps with an unsettled weather pattern is forecast next week. Rain and storms are possible (30-60%) Tuesday night into Thursday morning.
- A slight cool down is forecast to end the week.
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.DISCUSSION... Issued at 228 PM CDT Sat Sep 13 2025
A broad upper level trough was seen on the 19Z water vapor imagery with an upper ridge axis just southeast of the forecast area. Surface obs put a broad area of low pressure to the north of the forecast area centered near the NEB/SD state line. This has kept southwesterly low level flow across eastern KS with highs warming into the lower 90s.
There is not a lot of change to the going forecast with models still showing the upper trough moving out into the central plains on Sunday. Lapse rates out ahead of the upper trough continue to look modest, but are forecast to improve marginally into the afternoon as mid-level heights fall. Meanwhile the better bulk shear looks to be confined to the upper trough. So the severe risk remains conditional based on how much destablilzation can occur through the mid and high clouds. The latest CAMs seem to suggest more robust convection developing to the west of the forecast area underneath the trough with storms approaching the western counties after sunset as the boundary layer should be stabilizing. Weaker instability and shear over northeast and east central Kansas make strong storms unlikely. Think there should be enough sunshine across the eastern counties to warm temps to around 90 Sunday afternoon. More cloud cover is expected to keep temps in the middle and upper 80s across north central KS.
The NAM is showing a conditionally unstable airmass Monday afternoon as temps warm into the upper 80s with dewpoints still in the 60s. With the shortwave progged to lift north, it doesn`t look like there will be much forcing or lift to initiate convection. And the NBM keeps POPs below 15 percent. But the NAM does hint at the potential for an isolated shower or storm. So will need to keep an eye on this.
Confidence in the forecast diminishes beyond Monday as models continue to struggle with the overall synoptic pattern. The 12Z guidance is now about 12hrs slower with shortwave energy moving through the plains Tuesday showing better precip potential Tuesday night into Wednesday. By Wednesday the models show little agreement in how or where an upper low develops. Cluster analysis of the 00Z ensembles show there are about three scenarios with equal probabilities of occurring. With the lower predictability will stick with the NBM. A potential boundary with the upper low over the plains keeps some POPs in the forecast for Wednesday night and into Thursday. Temps are forecast to cool slightly but there is a spread of 6 to 9 degrees by Thursday so the forecast may be adjusted up or down as models come into better agreement.
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.AVIATION /06Z TAFS THROUGH 06Z MONDAY/... Issued at 1222 AM CDT Sun Sep 14 2025
Predominantly VFR conditions expected. Winds increase from the south again by mid- morning Sunday with gusts of 20-25kts most likely at KMHK. Confidence in timing and location of storms remains rather low, but have included a PROB30 group for TS at KMHK. Showers and storms could impact KTOP/KFOE from 23z through the end of the period, but confidence is not high enough to include.
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.TOP WATCHES/WARNINGS/ADVISORIES... None.
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DISCUSSION...Wolters AVIATION...Flanagan
NWS TOP Office Area Forecast Discussion