FXUS63 KEAX 261721 AFDEAX Area Forecast Discussion National Weather Service Kansas City/Pleasant Hill MO 1221 PM CDT Mon Aug 26 2024 .KEY MESSAGES... - Hot and Humid Conditions Continue - Periodic Shower/Storm Chances This Week - Slightly Cooler Temperatures Midweek, Still Hot && .DISCUSSION... Issued at 335 AM CDT Mon Aug 26 2024 Broad 594dam high continues to sit over the Central CONUS with stronger short-wave axis moving through the Intermountain West. Modest dCVA from the Front Range into the High Plains has supported a weak surface cyclone that is positioned in Central Nebraska and moving toward the northeast. Ahead of this, low-level flow remains southerly and maintains a high theta-e air mass. Temperatures in the mid to upper 90s are expected again. Dewpoints may reach the mid to upper 70s during the early afternoon, but clear skies are expected to promote another day of stronger boundary layer mixing that will ultimately drop dewpoints back into the lower 70s. Perhaps northern Missouri may miss out on some of the strong mixing and maintain higher dewpoints. Regardless, this will result in another day of triple digit heat index values, with most places pushing close to 105F. Therefore, will continue the Heat Advisory through this evening for the entire CWA. Early this morning, there is ongoing shower activity in far western Kansas under the area of large scale ascent with the trough axis just to the west of there. Some of the higher-level clouds may try to filter their way east. However, the ridge axis over the Missouri River Valley should hold steady, and push most of the kinematic support northward of the area that will keep conditions mostly dry. Tuesday, ridge axis slides further east as western trough begins to lift toward the Northern Plains. A hot and humid airmass will still be in place. Increasing cloud cover is expected for western and northwestern portions of the forecast area promoted by lift with the trough axis across the Central Plains. This is expected to keep air temperatures a few degrees cooler west of Hwy. 65 Tuesday afternoon. Areas eastward though may remain clearer through the afternoon that could allow another day of temperatures in the upper 90s with lower 70s dewpoints, yielding heat index values near 105F. Therefore, have extended the heat advisory until 8pm Tuesday evening for our eastern counties in central Missouri. Confidence in advisory criteria heat index values further west is lower. Areas of forecast cloud cover are demonstrating a spread in temperatures between 89F and 97F, while areas further east are most persistently between 94F and 98F. Tuesday may also bring light precipitation activity by late afternoon and into the evening hours. Although most of the mid-level support for lift will be well to the northwest, cloud-cover may result in a differential heating boundary that could eventually be a source of convergence for some shower activity. Without sufficient mid and upper-level flow, wind shear will very weak, and thus activity will not be organized and not expected to pose any kind of severe threat. Ensemble probabilities for measurable precipitation are around 15-20 percent, concentrated primarily north of Hwy. 36. HREF mean QPF for Tuesday Night activity though is very low, with just a few spots of QPF to around 0.10 inches. Therefore, will keep limited POPs in the forecast heading into Tuesday evening. Remainder of the week will feature a few mid-level troughs moving across the northern CONUS that will slowly force the H5 high toward the east coast. This keeps most of the upper-level support for robust precipitation activity well north of the area. There will be few localized vort maxima that may travel toward our area and bring additional chances for showers/storms. The lack of sufficient mid- level flow will continue to keep wind shear limited, and thus any activity that does develop will result in a minimal severe risk if any at all. Ensemble suites paint low-end probabilities across portions of eastern Kansas to Missouri Wednesday and Thursday. Strongest signal for notable rainfall/QPF is currently centered on Friday morning when a trough is expected to dig further south and completely push the mid-level high out of the region. Ensemble probabilities early Friday morning start to increase above 50 percent for any measurable precipitation. Medium range deterministic guidance keeps the stronger flow north of the area still, a pattern which would not favor any kind of robust severe weather threat. If this trough should shift southward, better flow may allow for more organized convective activity toward the end of the week. As for temperatures, cloud cover and shower activity should help keep conditions slightly cooler than what we have seen over the past few days, generally in the mid 80s though some spots may be able to hit the lower 90s if they miss out on precipitation activity. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 1221 PM CDT Mon Aug 26 2024 VFR conditions are expected through the period. Winds remain SW before becoming light and variable after sunset. A subtle front moves through the area Tuesday morning. Models show a slight chance for showers; however, high uncertainty in coverage combined with a higher likelihood of RA remaining east of the terminals keeps precip out of this set of TAFs. && .EAX WATCHES/WARNINGS/ADVISORIES... MO...Heat Advisory until 8 PM CDT this evening for MOZ001>005- 011>014-020>022-028>030-037-038-043>045-053-054. Heat Advisory until 8 PM CDT Tuesday for MOZ006>008-015>017- 023>025-031>033-039-040-046. KS...Heat Advisory until 8 PM CDT this evening for KSZ025-057-060- 102>105. && $$ DISCUSSION...Krull AVIATION...Pesel