254 FXUS63 KEAX 261729 AFDEAX AREA FORECAST DISCUSSION National Weather Service Kansas City/Pleasant Hill MO 1229 PM CDT Thu Sep 26 2019 .Discussion... Issued at 345 AM CDT THU SEP 26 2019 Outside of the MCS over southern Missouri, our area is relatively impact free as upper level ridging and surface high pressure build into the region. This trend will make for a beautiful fall day with mostly sunny skies and temperatures only getting into the mid to upper 70s with dewpoints in the 50s! This trend unfortunately will be short-lived as a shortwave trough moves through the northern plains with low levels shifting to a southerly flow on Friday. This shortwave will help develop a low pressure region from KS up into MN Friday morning. Warm moist low level flow will cause some stratus and light drizzle possible overnight into the morning, but also increase dewpoints into the 70s across the region. If cloud coverage does shift northward, which guidance indicates, then there will be enough heating to get our temps into the mid 80s with a swath of higher MLCAPE near 3000 J/kg ahead of the developing cold front. The timing of this front, and associated mid level accent to break the cap, will be key to severe weather coverage and intensity. Most guidance has this boundary enter the area late in the afternoon with convective initiation occurring just before sunset. If this timing holds true, then the possibility of discrete supercells ahead and along the boundary is possible through sunset. The large CAPE, steep mid-level lapse rates (8C/km), and effective bulk shear near 40ks will lead to possible large hail and damaging winds being the main threat. The hodographs are relatively straight, but do lean towards right moving supercells in the warm sector. The storm motion and shear vectors will be parallel to the boundary which will be the limiting factor for widespread severe weather as it will allow for rapid cold pool development. This will change the storm mode to more of a linear mode. The hodographs also indicates that training storms along the boundary with PWAT values near 2" so flash flooding will come into play after sunset as the boundary stalls over our area. This boundary does appear to stall over our area through Saturday before finally moving north as a warm front as the next low pressure system develops along the front range Sunday. The QPF focus does shift around during this timeframe so this could be more of a widespread higher QPF event than all of it localized. Overall we are looking for widespread 2-3" with higher totals over north central Missouri close to 4". This could aggravate already high rivers in central Missouri and will need to be watched. Monday through Tuesday we will stay in the warm sector of a larger frontal system over the plains allowing above average temperatures and humidity to start the week. This will change Tuesday night into Wednesday as the cold front from the low pressure system becomes stationary over our area between a deep low pressure system over the Rockies and strong high pressure over the SE US. This pattern could be impactful as plenty of moisture will be available from the Gulf of Mexico and the Pacific, all merging over this boundary. This pattern sets up a potential major hydro event if it all plays out as guidance indicates now and will need to be watched as we get closer to the work week for any trends or changes with this system. && .Aviation...(For the 18Z TAFS through 18Z Friday Afternoon) Issued at 1215 PM CDT THU SEP 26 2019 VFR conditions should persist through the afternoon and evening hours. MVFR ceilings will develop through midnight, at all sites, and remain in place through the end of the period. Southeasterly winds will shift more south and southeast through the morning, increasing ahead of the approaching frontal boundary. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ Discussion...Barham Aviation...Kurtz