070 FXUS63 KEAX 172330 AFDEAXArea Forecast Discussion National Weather Service Kansas City/Pleasant Hill MO 630 PM CDT Wed Sep 17 2025
...Updated 00z Aviation...
.KEY MESSAGES...
- Strong to marginally severe storms this afternoon-evening. Strong to damaging winds are the most likely hazard.
- Multiple periods of storms possible through Thursday night.
- Additional precipitation chances Saturday - Tuesday.
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.DISCUSSION... Issued at 248 PM CDT Wed Sep 17 2025
A stagnant upper-level pattern, with what looks like a high-over-low Rex block over the middle the country, is keeping the central to northern Plains unsettled. Eastern KS and MO are on the eastern side of the low of the Rex and that is helping to keep the area warmer than normal, for this time of year. That warmth is also leading to mainly diurnally driven showers and storms in the area. As I am writing this sentence (1830Z) it appears that the outflow boundary that pushed eastward earlier is helping to initiate new convection from near Clinton, MO to SE IA. With weak shear, nearly 2000 J/kg of MLCAPE available, and an inverted-V type sounding, strong to damaging wind gusts look like the most likely hazard. There may also be some small hail, and the most robust storms could perhaps produce quarter size hail. Additionally, locally heavy rain is also expected given the scattered nature to the storms.
Over the next few days, there are multiple other chances for showers and storms in the area. The most likely time frame looks like Thursday afternoon through the overnight hours. The low portion of the Rex block begins to break down and shift east. This will lead to vorticity advection into eastern KS and western MO which helps to force showers and storms Thursday afternoon through the overnight hours. There is a fair amount of variability in forecast CAPE, about 800 J/kg at the 10th percentile, to around 2000 J/kg at the 90th percentile, which adds uncertainty to how strong storms may be. Additionally, models show relatively stronger flow rounding the base of the shortwave moving through, which would support stronger shear. But even this varies significantly, adding uncertainty to the potential strength of any convection. When looking at probabilities of CAPE and Shear, it seems unlikely that we`ll have the combination necessary for severe convection. But with the potential for nearly 2000 J/kg of CAPE and 20-25kts of deep-layer shear Thursday afternoon and evening, can`t rule out a few strong to marginally severe storms.
Precipitation chances decrease Friday with high pressure over the area. Friday night/ early Saturday, the low-level jet strengthens and noses into eastern KS and western MO. This will lead to additional chances for storms early Saturday that may linger into the morning hours. This general pattern continues into early next week with continued low chance PoPs (20-40%) into Tuesday morning. It isn`t until the middle of next that a dry period returns.
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.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/... Issued at 627 PM CDT Wed Sep 17 2025
Most of the thunderstorm activity for the remainder of Wednesday evening should be east of the Kansas City Metro and STJ terminals. Activity should diminish after sunset. There is some potential for more development Thursday morning, with then isolated to scattered activity into Thursday afternoon. Most cloud bases should be VFR, though a stronger shower or storm could result in brief IFR conditions if they occur directly over the terminal.
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.EAX WATCHES/WARNINGS/ADVISORIES... MO...None. KS...None.
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DISCUSSION...CDB AVIATION...Krull
NWS EAX Office Area Forecast Discussion