Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO
Issued by NWS Kansas City/Pleasant Hill, MO
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254 FXUS63 KEAX 152344 AFDEAX Area Forecast Discussion National Weather Service Kansas City/Pleasant Hill MO 644 PM CDT Sat Jun 15 2024 .KEY MESSAGES... - Isolated/Scattered Storms Possible This Evening - Warm and Humid Conditions This Week - Additional Shower/Storm Chances Throughout This Week && .DISCUSSION... Issued at 343 PM CDT Sat Jun 15 2024 Ridge axis has passed through the area with short-wave trough working across the Central Plains this afternoon. An area of stronger upper-level divergence appears to have aided in lift that produced the thunderstorm and shower cluster early Saturday morning across our western CWA. With the surface anticyclone shifting eastward, weak southeasterly to southerly flow attempted to push thermal boundary back northward as a warm front. However, the outflow boundary for early morning convection has caused the front to stall just south of Interstate 70. With weak dCVA, expecting modest surface pressure falls through this evening and persistent southerly flow to continue to provide more moisture advection. Convergence along the warm front that appears to have been strengthened through differential heating this afternoon could provide a point of more convection initiation heading into the evening hours. CAM solutions have been wavering on redevelopment this afternoon, which is leading to lower forecast confidence. Overall, mesoscale environment could support a few stronger to low- end severe storms if storms are able to develop. The boundary layer remains warm and moist, with temperatures in the lower 90s and dewpoints crossing above 70 degrees. Mid-level lapse rates are looking more robust today then they did yesterday, which is yielding greater MLCAPE values for the southwestern third of the forecast area, current SPC Mesoanalysis displaying 3000 J/kg. In this same area, where strong differential heating occurred, visible satellite imagery has been showing stronger cumulus clouds developing over the past hours indicating the boundary destabilization on the warm side of the boundary. The one limiting factor is that the better deep layer shear is closer to the stronger mid-level flow, which is more in northern Missouri and eastern Nebraska and western Iowa. This may make it harder for convection to organize, but the thermodynamics and lift with a second area of upper-level divergence may lead to storms that could produce some quarter size hail and downburst wind gusts. Low-level shear and elevated SRH could be present along the boundary but will remain very localized. Heading into this evening and overnight, main mid-level vort max moves toward the area and provides continued H5 height falls, and also shifts the warm front northward. Additional development is possible, but the CAMs have also been struggling to provide a consistent solution. Given the high theta-e boundary layer, will keep POPs between 15 and 30 percent in western portions of the CWA through the overnight hours where the instability axis will remain. Most of these may end up just being general airmass thunderstorms. Far northwestern counties may see more robust structure to thunderstorms, but currently expecting supercell structure and more prominent threat, including low-end tornado threat, to be in eastern Nebraska and western Iowa. Will continue to monitor northwest Missouri as the evening progresses. Temperatures will remain above normal through the end of the week with an anomalously strong ridge over the east coast helping to set up persistent southwesterly flow through the week. Most ensemble suites including those amongst most NBM members are hold over 80 percent chances for exceeding 90 degrees on most days through next week. The GEFS has been a bit cooler. The extremes of the temperatures will depend on the how the strong the ridge of the east is and where the PV anomaly over the Pacific Northwest sets up. Within the southwesterly flow expecting multiple embedded short-wave troughs and vort maxes to ride through that will bring chances for precipitation. Currently, the greatest signals and ensemble probabilities are focused on Tuesday Night through Wednesday across most of our forecast area with lower end chances continuing into Thursday. Thermodynamically, the high theta-e boundary layer would be supportive of stronger storms across eastern Kansas to central Missouri. However, the stronger flow is currently progged to be further west and northern of our area, which may limit severe potential. Colorado State Machine Learning probabilities for severe storms continue to favor a corridor from western Kansas to the western Great Lakes for more active severe weather. However, if stronger flow is able to sink further south, this may be able to provide more organization to the storms during midweek. While temperatures are very warm, precipitation may help to provide some relief. Box and whiskers plots of temperatures next week for medium range ensemble forecast do show larger inner-quartile spreads for temperatures, likely due to differences timing of shower activity. && .AVIATION /00Z TAFS THROUGH 00Z MONDAY/... Issued at 643 PM CDT Sat Jun 15 2024 VFR conditions are expected to last through the TAF period. Some uncertainty exists with the duration for showers and storms over the next few hours. Once the storms move to the east, conditions will improve with some gusts up to 20 mph during the day. && .EAX WATCHES/WARNINGS/ADVISORIES... MO...None. KS...None. && $$ DISCUSSION...Krull AVIATION...Collier