657 FXUS63 KTOP 280506 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 1206 AM CDT Tue Aug 28 2018 ...Update to aviation forecast discussion... .SHORT TERM...(This evening through Tuesday) Issued at 325 PM CDT Mon Aug 27 2018 An upper level trough was positioned across the northwest with perturbations moving around the base of the trough. Lead wave was moving into the Dakotas with a second wave moving into Idaho. Other energy may move northeast in southwest flow aloft out of the southern Rockies across the area overnight. CAMS suggest that isolated convection will once again develop within the low level jet overnight within the moisture plume extending from the Texas Panhandle into southwest Iowa. Have inserted chances after 09Z as in the prior forecast and models suggest that scattered activity should wane during the mid to late morning hours. Given the strong winds off the surface and a mixed lower boundary layer could see a few strong wind gusts in the morning. During the day on Tuesday, the upper trough will move across the northern Plains with trailing energy further south into the central Plains. This will move a cold front southward across northeast Kansas through the day. The front looks to be in north central Kansas toward 12Z then move southeast and exit the CWA in the evening hours. Forecast soundings ahead of the boundary show upwards of 4000 J/kg of ML CAPE along with 30 kts of effective shear along with steepening mid level lapse rates. Strong to severe storms are possible from late afternoon through the evening hours with damaging winds and hail the main hazards. High precipitable water values near 2.2 inches pool along the boundary owing for high precipitation efficiency as well. .LONG TERM...(Tuesday night through Monday) Issued at 325 PM CDT Mon Aug 27 2018 High pressure builds into the area in the wake of the system on Wednesday with cooler temperatures around 80 degrees. For much of the rest of the week and into the weekend a zonal flow aloft will prevail across the central Plains with perturbations ejecting eastward through the period bringing periodic chances for showers and thunderstorms. Wednesday night looks like elevated convection will be possible later in the night with the passage of one of the minor waves and moisture return to the north. Models differ with the ejection of another mid level trough out into the central Plains early next week. Highs will be mainly in the 80s, with highs friday in the low to mid 90s. && .AVIATION...(For the 06Z TAFS through 06Z Tuesday night) Issued at 1203 AM CDT Tue Aug 28 2018 For the 06z TAFs, gusty southerly winds will persist through the TAF period, with a 45-55kt LLJ resulting in LLWS concerns once again through Tuesday morning. This LLJ may help to support some isolated thunderstorm development near KTOP/KFOE around sunrise, so inserted VCTS. With a cold front tracking southward into the region on Tuesday, there is a better potential for scattered thunderstorms to develop mid/late afternoon into the evening hours. While there is fairly high confidence in this storm development, there are still minor model discrepancies with the time and location of this storm initiation, so just have VCTS mentioned at this time and anticipate being able to add more specific timing in future TAF updates. Behind this frontal passage, winds will veer to the north, with models showing MVFR cigs developing over the area by mid/late Tuesday evening. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...53 LONG TERM...53 AVIATION...Hennecke