696 FXUS63 KTOP 110453 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 1153 PM CDT Sat Aug 10 2019 .SYNOPSIS... Issued at 338 PM CDT Sat Aug 10 2019 Afternoon water vapor imagery shows a mid-level low slowly moving onshore along the Pacific Northwest coast. A mid-level ridge is centered over TX. Weak waves have been noted at times in the southerly flow in between the two mid-level features. At the surface, high pressure is located over the Great Lakes region. An area of lower pressure is near Sioux City and a diffuse surface front extends southwestward across central Nebraska. Closer to home, some lingering cloud cover remains overhead, which has likely held back afternoon temperatures a tad. Higher dewpoints, however, crept into the area this morning and early this afternoon, creating rather sultry conditions. There are also a few showers showing up on radar in central KS which could be associated with some weak low level WAA. && ...Update to aviation forecast discussion... .SHORT TERM...(This evening through Sunday) Issued at 338 PM CDT Sat Aug 10 2019 The main question for the short-term portion of the forecast period is the chance for storms tonight. Daytime heating has allowed CAPE values to increase to 3000 to 4000 J/Kg across the region. Bulk shear is marginal, mainly between 25 and 30 kts. Short-term high resolution models all want to develop convection this evening in western KS and move it eastward overnight. There does not appear to be any good wave in the flow aloft to generate precipitation, so thinking that WAA around 700 mb where winds increase this evening is the most likely forcing mechanism. Above 700 mb, ample instability looks to remain in place into the overnight hours, however, shear will remain fairly weak. Thus, confidence in how organized a cluster of storms will be as they move east is not overly high. The best chance for storms tonight looks to be primarily in central KS between 06Z and 12Z. Precipitable water values are expected to be around 2.0 inches, so heavy rain will be likely with thunderstorms. 1.0 to 2.0 inches of rain, with locally higher amounts will be possible, especially south of a line from Concordia to Emporia. Isolated flash flooding could occur but have opted to not go with a watch at this time since the concern for more widespread flooding is not high. Will monitor trends through the evening. Aside from heavy rain, a few stronger storms could be capable of producing severe criteria wind gusts (58 mph or higher). However, the chance for widespread severe weather will generally remain low. The afternoon hours tomorrow are expected to be dry. Heat will become the main concern with highs forecast to warm to near 90 degrees, coupled with dewpoints in the mid to upper 70s once again. The highest heat index readings will approach 105 degrees south of I-70. .LONG TERM...(Sunday night through Saturday) Issued at 338 PM CDT Sat Aug 10 2019 The next chance for storms will be Sunday night. The better forcing at that time should remain to the north of the area, closer to the surface frontal boundary. Thus, have the best chance for storms Sunday night along the KS/NE state line. Again, heavy rain and strong winds could accompany some storms. Monday should be the hottest day of the next several with heat index values between 100 and 105 from I-70 southward. An advisory might be warranted but will wait until we get a little closer to get a better handle of exact temps and dewpoints. The upper low near the Pacific coast will work eastward across the northern tier of the country, which will allow the surface front to slide southward into the forecast area late Monday. Thunderstorms could develop along the front as it moves southward Monday night. Slightly cooler and drier conditions are then expected through the middle of the workweek under the influence of higher pressure. A gradual warming trend is forecast into the end of the week and next weekend with higher pressure building aloft. && .AVIATION...(For the 06Z TAFS through 06Z Sunday night) Issued at 1139 PM CDT Sat Aug 10 2019 For the 06z TAFs, main focus is on the complex thunderstorms over western KS that will track eastward toward the TAF sites overnight into Sunday morning. Cigs may be borderline VFR/MVFR with these storms with reduced vis possible, but confidence is low with how far vis may drop as it depends on where the heaviest rain tracks. Cannot rule out the potential for some strong storms to develop near the TAF sites, which could result in some gusty winds of 30-40 kts. However, confidence in the potential or location of any strong storms is too low to warrant a mention in the TAFs at this time. Precipitation should diminish by mid to late morning. Showers and storms may redevelop just north of the TAF sites by Sunday evening with increasing chances into the overnight hours. Also, with an increasing LLJ Sunday night, LLWS concerns are possible by the end of the TAF period, but will evaluate this further in future updates. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...Teefey SHORT TERM...Teefey LONG TERM...Teefey AVIATION...Hennecke