FXUS63 KEAX 262323 AFDEAX Area Forecast Discussion National Weather Service Kansas City/Pleasant Hill MO 623 PM CDT Mon Aug 26 2024 .KEY MESSAGES... - Hazardously hot conditions continue through today for far eastern KS and western MO (including the KC Metro) and tomorrow for far northern and central MO. - Pop up showers and thunderstorms possible. Best chances are late overnight tonight across far northern MO with more widespread chances Thursday and Friday across the whole region. - Relatively cooler conditions starting midweek with more seasonal towards the weekend. && .DISCUSSION... Issued at 318 PM CDT Mon Aug 26 2024 An expansive high pressure continues to reside over the central CONUS. This has kept conditions hot and humid over the area. Heat index values once again crest 105F with some areas approaching 110F, especially across northern MO as the axis of warm, moist southerly flow advances slightly northward. Typically, broad scale upper level high pressure leads to clear, dry, and hot conditions; however, tight directional shifts around the center of the high combined with small perturbations at the 850mb level are tapping into the mildly unstable elevated environment which caused some showers across the southern portions of the coverage area late this morning. The strong high kicks flow north and around our area; however, a strong trough and associated cold front does dig into the area overnight tonight into Tuesday morning. Again much of the activity remains north into NE and IA, but there is a chance some more organized showers and storms reach into northern MO during the overnight. It is not unreasonable to suspect a chance for an isolated strong to severe storm as storms are able to sustain in the "cooler" and more saturated nocturnal environment. The most likely hazards being damaging winds and hail. Models become a little more uncertain post sunrise Tuesday. Preceding runs have been keeping conditions initially dry; however, CAMs have been a little more active over the past few iterations. This seems to be due to models either A) pushing precipitation with the front through the region during the morning or B) washing the front out as daytime heating begins after sunrise leaving several remnant boundaries and areas of differential heating. These may result in isolated pockets of convection that can tap into the mildly unstable environment. All of this to really say that the pattern of pop-up showers and thunderstorms looks to continue. Any convection is expected to be relatively weak and disorganized; however, isolated pockets of heavy rainfall are possible given the >1.5 in. PWAT values. Where confidence is high is that as the boundary passes through the area. Cloud cover across the western half of MO will start the trend of lower temperatures and heat index values. While temperatures remain in the 90s and heat indicies near 100F, hazardous heat looks to be mainly contained across the eastern portions of MO with areas east of US-65 covered by a heat advisory for Tuesday. Elevated dew points combined with unobstructed heating look to push temperatures and heat indicies toward hazardous levels across this area. The cooling trend continues as a weak upper level low moves onshore along the TX Gulf Coast in tandem with digging Pacific NW trough to the NW. This results in the resident central CONUS high breaking down creating more zonal flow and opening up the opportunity for cooler conditions later in the week. Temperatures begin the cooldown as drier air from the NW moves into the western portions of the area tomorrow. This continues into Wednesday cooling a little further before a strong push of cooler Canadian air from the NW moves toward the region Thursday and Friday. This front looks to bring a more widespread chance for showers and thunderstorms. Guidance has remained fairly course in coverage thus far mainly due to the resilience of the high over the central CONUS. It is expected that many areas should see precipitation chances during the end of the week however exactly where remains a bit uncertain. Where confidence is high is that behind this front is more seasonal temperatures with weekend highs returning to the low to the mid 80s. && .AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/... Issued at 620 PM CDT Mon Aug 26 2024 VFR conditions through the period. Upper level cloud cover (>10K feet) will be on the increase across the region after 09Z Tuesday. A weak boundary may try to drop southward across the region Tuesday afternoon, potentially generating isolated thunderstorms after 22Z. Confidence and coverage is low enough that mention was left out of the terminals at this point. && .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...Pesel AVIATION...BT