908 FXUS63 KEAX 081057 AFDEAX Area Forecast Discussion National Weather Service Kansas City/Pleasant Hill MO 557 AM CDT Tue Jul 8 2025 ...Updated 12z Aviation... .KEY MESSAGES... - Stratiform Showers Through This Morning - Outflow Boundaries May Initiate New Convection This Afternoon In Central Missouri, Depending on Recovery - Drier Wednesday; Active Toward End of Week && .DISCUSSION... Issued at 355 AM CDT Tue Jul 8 2025 Thermal boundary from south of Omaha to near Kansas City has pushed a bit further eastward, but overnight this generated a CAPE gradient that helped keep the MCS over eastern Nebraska going for a longer period of time, even when it became outflow dominant. Finally as of 08z, seeing a substantial downward trend in the stronger precipitation cores. There is not much deep layer shear to support it, and finally appears to be cut-off from the instability it could draw in overnight. Expansive trailing stratiform rain shield has developed across most of the forecast area, and should persist through most of the morning. Eventually should see H5 short-wave exit, and subsidence start to clear this out by late morning. With this MCS holding together further southeast than yesterday`s CAMs runs had projected, the mesoscale environment has been and will continue to altered substantially past sunrise this morning. The main question, is where does the outflow boundary stall. A few runs after 06z this morning of the HRRR has placed this outflow from Linn County Kansas east-northeastward toward Howard and Cooper Counties Missouri. That then initializes new convection around 21-22z, which would align with peak heating. Another mid-level vort maxima will be moving across the region at some point this afternoon, with potential for that to induce surface pressure falls from the Central Plains to the middle Mississippi Valley. If these come together between 18-22z this afternoon, and there is enough destabilization in this zone of convergence, stronger thunderstorms could be favorable. Main threat would be severe wind gusts. As has been the story for most of the activity over the past several days, the deep layer shear has been weak, thus hard for updrafts to organize when they initiate over Missouri. If convection develops, most of this should push southeastward toward the Ozarks through the remainder of the evening. Have concentrated POPs mainly south of Interstate 70 for this afternoon. If the outflow boundary pushes further southeastward and stratiform shield lingers long enough to prevent insolation, our forecast area may see very little in the way of new development. The SPC SWODY1 marginal risk for winds is conditional on initiation of storms this afternoon. Wednesday, deterministic guidance has started to depict a subtle eastward shift of the broad anticyclone over the southwest CONUS, that may actually introduce H5 height rises and broader subsidence, pushing short-wave activity further eastward. As a result, precipitation chances for most of Wednesday have been on a downward trend compared to previous forecasts. GEFS and other ensemble suites are showing decreasing probabilities for 0.10 inch of QPF on Wednesday. It still appears that a higher theta-e boundary layer may be in place though, so if there is any destabilization cannot completely rule out a few isolated showers to initiate within a cumulus field. Temperatures will still be in the upper 80s to lower 90s, with dewpoints generally in the mid 60s to lower 70s. Thursday, stronger PV anomaly promotes troughing over the western CONUS that will begin to de-amplify the ridge. Stronger dCVA into the Front Range begins to promote lee cyclogenesis, with pressure falls extending eastward across the Plains. Thursday afternoon, this may increase convergence, and even provide a mid-level vort maxima to generate isolated to scattered thunderstorm activity. We may start to see an increase in deep layer shear by Thursday, which may allow for better organization of storms if they are able to develop. SPC SWODY3 currently highlights this with a marginal risk. Stronger mid-level vort maxima is progged to move through Friday into Saturday, capable of bringing more widespread shower and thunderstorm activity heading into the weekend. Deep layer shear should be much greater, as stronger mid-level jet streak moves overhead. The main question for Friday and Saturday activity is where will the better surface forcing be located at, that could end up being the controlling factor for stronger to severe storms. QPF may also need to be monitored closely for hydro related issues headed into the weekend. Slightly cooler air settles in Saturday into Sunday, with high temperatures forecast in the upper 70s to lower 80s. && .AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/... Issued at 554 AM CDT Tue Jul 8 2025 Showers and weak thunderstorms associated with overnight MCS have shifted into Central Missouri and will keep pushing east- southeast. Seeing some new development over eastern Kansas but most of this has been short-lived. A few hours of showers are possible at STJ and the KC Metro terminals this morning, and may bring brief MVFR conditions. Winds in general should be light, perhaps a few gust to 20 kts with shower activity. New thunderstorm development is possible over Central Missouri this afternoon. Current expectation for new development would east of the KC Metro terminals, therefore, will not place in new development into the 12z TAFs. && .EAX WATCHES/WARNINGS/ADVISORIES... MO...None. KS...None. && $$ DISCUSSION...Krull AVIATION...Krull