


Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO
Issued by NWS Kansas City/Pleasant Hill, MO
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029 FXUS63 KEAX 101138 AFDEAX Area Forecast Discussion National Weather Service Kansas City/Pleasant Hill MO 638 AM CDT Thu Jul 10 2025 ...12z Aviation Update... .KEY MESSAGES... - Decaying Thunderstorm Complex In Nebraska May Bring Showers/Storms to Northwest and Northern Missouri Thursday Morning - Isolated/Scattered Storms Possible Thursday Afternoon and Evening Primarily Along and North of Interstate 70 - Organized Showers/Storms Friday, Especially The Evening; Severe Storms Possible && .DISCUSSION... Issued at 213 AM CDT Thu Jul 10 2025 Short-wave trough has ejected across Central Nebraska during the overnight hours into early morning Thursday that has generated a line of showers. As of 05z, most of the line has become outflow dominant as seen on off the KOAX radar. Outflow boundary winds of 40- 50 MPH as of 05z had still be reported in eastern Nebraska. This short-wave will continue to move eastward, and there is MUCAPE gradient that tracks from eastern Nebraska into North Central Missouri that the storms may try to follow. However, as the outflow advances ahead of it, the inflow that storm complex likely gets cut off. MSLP analysis in the vicinity of this does show a stronger convective response with lowered surface pressure that may be deepening a bit with the mid-level vort maxima overhead. This could end up providing extra lift to maintain showers and isolated thunderstorm potential as it drifts southeastward. If this cluster does hold up as it gets into northwest Missouri, cannot completely rule out isolated 60 MPH gusts, but gusts above 40MPH are certainly possible especially with a localized stronger pressure gradient. At the moment not seeing evidence of an MCV associated with the convection, but may not be out of the question as we progress into the early morning hours of Thursday. Through the 00z runs, the HRRR continues to be bearish about convection lasting into northern Missouri, along with the NSSL-WRF. Experimental RRFS depicts stronger cores making into north-central Missouri, but this solution did not depict and outflow boundary as early as we have already seen. With the short-wave passing through and potential for convergence along the outflow boundary, will maintain slight chance POPs (15-24%) for areas mainly north of Hwy. 36 through Thursday morning. Heading into the afternoon hours today, a PV anomaly will promote stronger troughing over the western CONUS that is expected to de- amplify the 594dam high that has been sitting over the desert southwest for the past several days. Strong dCVA from the Intermountain West to the Front Range has already started providing lift, and can see surface pressure lowering as cyclogenesis takes place across most of the High Plains. RAP, HRRR and other CAMs have been suggesting an area of surface troughing to extend eastward along the KS-NE stateline and into northern Missouri. This is also where we may potentially have remnant outflow boundaries from the overnight activity, where lingering cloud cover may have potential to promote differential heating. The HRRR has been inconsistent from run to run overnight with respect to redevelopment Thursday afternoon into evening. The NSSL-WRF has been developing stronger convection across southern Nebraska into far northern Kansas but then decays as it gets into northern Missouri. Some CAM runs have tried to sneak some activity as far south as the Interstate 70 corridor, including Kansas City, but have not seen overly persistent trends at least through the 03z CAM runs. Most of the CAM spread seems to be attributed to recovery and destabilization through the afternoon (not trying to sound like broken record, but a persistent pattern leads to persistent weather, and persistent uncertainty with weakly forced convection). HREF mean MUCAPE values show a narrow corridor of 1500-2000 J/kg that develops essentially between Hwy. 75 to roughly the western third of Missouri. The one change that is coming to the environment today though, will be stronger 850-600mb southwesterly flow, that will setup a more pronounced EML from the eastern Plains into the lower Missouri River Valley. This may make it easier to recognize higher CAPE values, but could also result in a strong capping inversion especially through Thursday afternoon (potential for 700mb of temperature in excess of 12C). Increasing mid-level flow associated with passing vort maxima and H5 height falls will also start to gradually increase deep layer shear. With a slightly better kinematics in play, will maintain slight chance to chance POPs for portions of the forecast area northward, with isolated to scattered activity to around I-70. Most initiation though will probably have to occur over Central Kansas, or more likely Central Nebraska in the afternoon, where the forcing should be stronger with better instability, and this would move eastward through the afternoon into the evening. While better mid- level lapse rates and perhaps better shear could support some hail with discrete multicells, isolated to scattered activity may congeal by the time it would reach far eastern or northeastern Kansas, transitioning mainly into a wind threat once again. Confidence continues to remain rather low in storm potential for Thursday afternoon into evening. While the the forcing looks somewhat better in more recent model runs compared to last night`s model runs for Thursday afternoon, it`s not a slam dunk for it to realized. If we observe a clear MCV on satellite late this morning and afternoon, or strong differential heating on some kind of mesoscale thermal boundary, that could be a signal of an increasing storm threat. Have started to look as some the MPAS core model output, and so far seeing a wide variety of solutions as well. Friday, continuing to see a strong signal for a deeper mid-level trough and stronger vort maxima to move across the area, dragging along a deeper surface cyclone with more baroclinicity along a warm front to our north and cold front moving across the Central Plains. Deterministic guidance has been converging on a solution that depicts two distinct rounds of stronger H5 height falls, the first through Friday mid-afternoon, and the second later in the evening. Southerly flow should increase, providing another push of stronger theta-e advection to the lower Missouri River Valley. This should result in stronger CAPE through the area and healthy warm sector, along with surface pressure falls extending eastward into the Middle Mississippi River Valley. The 00z CAMs cover the fist half of the event through Friday early evening, and do show isolated to scattered convection occurring along a warm front and the first mid- level vort maxima. The main question for Friday afternoon activity though will be capping. We may once again have a stronger EML present, and while steepening mid-level lapse rates, may need a bit more forcing then could be available to recognize stronger storms. The better wind shear Friday afternoon may also be further west of Central Kansas, as it will be tied to the second, stronger vort maxima progged to move across the area. Heading into Friday evening, forcing will continue to increase as a cold front moves eastward. This is expected to be enough to break the cap, and initiate convection heading into the evening where severe threat will increase. A quick glance at a few model soundings ahead of the cold front suggest moderately strong mid-level lapse rates present over a moist unstable boundary layer, with increasing deep layer shear that would support organized convection capable of becoming severe. Damaging winds will be the most prevalent threat Friday evening, especially as cells congeal into either a line or some kind of MCS. If things pan out for more discrete storms initially before congealing, severe hail could occur, though the melting level will be fairly high, which could reduce hail size. Depending on residual outflow boundaries or convection, low-level wind shear could support a low-end tornado threat with discrete storms, this is highly conditional. In addition to severe storms, deeper warm cloud processes along with PWATs exceeding 1.75 inches will lend to efficient rainfall production potential. With heavy rainfall would come hydro concerns for flooding. However, if the system moves at a decent speed, any type of MCS complex may end up progressive enough to limit flooding issues. Preceding afternoon activity on Friday, if it occurs, would also impact this. Saturday and beyond, large scale pattern continues to be conducive to a train of mid-level vort maxima passing through the area, though stronger belt of westerly flow may remains much further northward of the area. Ensemble guidance continues to depict multiple periods of 40-50% probabilities for QPF of at least 0.10 inches in a 24 hours period through much of next week. Depending on how diurnal trends destabilize will control any severe potential that may come up next week. If the stronger mid-level flow stays north of the area, deep layer shear may be hard to come by for most of the opportunities for precipitation through next week. Temperature wise, Saturday and Sunday are expected to feature cooler temperatures after the passage of the cold front. Then through the next work week, temperatures bounce up and down between the lower 80s and lower 90s. && .AVIATION /06Z TAFS THROUGH 06Z FRIDAY/... Issued at 1203 AM CDT Thu Jul 10 2025 Morning -SHRA/-TSRA has largely dissipated across the TAF sites, yielding a couple hours of VCSH for the trio of KC Metro sites. Otherwise VFR conditions expected to prevail throughout with southerly flow increasing by the afternoon to around 10 to 14 kts sustained and gusts up to around 20 kts. && .EAX WATCHES/WARNINGS/ADVISORIES... MO...None. KS...None. && $$ DISCUSSION...Krull AVIATION...Curtis