286 FXUS63 KTOP 161949 AFDTOPArea Forecast Discussion National Weather Service Topeka KS 249 PM CDT Tue Sep 16 2025
.KEY MESSAGES...
- A few isolated showers and storms may form this afternoon.
- A minor disturbance will provide a 20 to 40 percent chance for showers and storms late Tonight through Wednesday.
- Wednesday evening into early Thursday morning the a more amplified upper level disturbance will move east across the area providing a 60-80% chance for showers and storms.
- Cooler temperatures finally move into the area Thursday into Friday with season normal temperatures through the weekend into early next week. There may be a few isolated showers or storms.
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.DISCUSSION... Issued at 240 PM CDT Tue Sep 16 2025
Early this afternoon an upper level trough was located across the central Rockies. A high over low block was located across the eastern US with the upper low centered across the NC/SC border and a broad upper fridge axis across the northeast, northward into northern Quebec, Canada. A broad upper low was located off the British Columbia, Canada coast.
At the surface, a lee surface trough was located across eastern CO and extended southward across eastern NM. A complex of storms due to upslope flow and DCVA ahead of the central Rockies upper level trough have formed across western NE and southwest SD. A stationary front was located along the SD/NE border, then extended northeast across western MN as a surface cold front.
Today through Tonight:
Most CAMs do not show much deep moist convection developing this afternoon through Tonight. Surface heating combined with any minor perturbation rounding the central Rockies H5 trough may provide enough ascent for isolated showers and storms this afternoon through the early evening hours. Any isolated storms that develop should dissipate around sunset. Effective shear will be under 20 KTS and MLCAPES will be around 1500 J/kg. A pulse type storm could produce gusty winds. The convective complex across western NE should remain well north of the CWA.
Wednesday through Thursday night:
Rain chances will increase as the central Rockies H5 trough slowly shifts east across the Plains. The combination of increasing DCVA ahead of the H5 trough combined with convergence ahead of a weak front and isentropic lift on the northwest side of the surface front will provide periods of showers and isolated to scattered thunderstorms. The effective shear increases through the day Wednesday as the H5 trough approaches but increasing cloud cover may keep MLCAPEs below 1500 J/kg, thus the the thunderstorms should stay below severe levels. The HREF shows the greatest probabilities of receiving 0.25" of qpf will be Wednesday night into Thursday morning with a 45 to 70 percent across the CWA. The NBM PoPs will range between 60 to 80 percent late Wednesday into Thursday morning. The NBM forecast QPF ranges between 0.5" across the southeast counties to around 0.8" elsewhere across the CWA.
Friday through Tuesday:
The extended range models show the H5 trough across the Plains shifting east across the Mid MS River Valley on Friday. Any lingering showers Friday morning will shift east into MO. Friday afternoon and Friday night look dry.
Saturday through Tuesday the CWA will be under west-northwest flow aloft. There may be slight chances for showers and thunderstorms through the period as embedded perturbations within the west- northwest flow dig southeast across the Plains. By the end of next week an H5 ridge will amplify across the Plains and may bring back the warmer weather.
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.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/... Issued at 1225 PM CDT Tue Sep 16 2025
Expect VFR conditions for the next 24 hours. A few isolated showers and storms may develop this afternoon and Tonight but confidence is too low to include into TAFs. Several CAMs show a better chance for scattered showers and isolated storms at KMHK after 12Z WED, with isolated showers and storms at KTOP and KFOE.
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.TOP WATCHES/WARNINGS/ADVISORIES... None.
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DISCUSSION...Gargan AVIATION...Gargan
NWS TOP Office Area Forecast Discussion