Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO
Issued by NWS Kansas City/Pleasant Hill, MO
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495 FXUS63 KEAX 190520 AFDEAX Area Forecast Discussion National Weather Service Kansas City/Pleasant Hill MO 1220 AM CDT Sun May 19 2024 ...Updated 06z Aviation... .KEY MESSAGES... - A few brief, isolated storms remain possible this evening. - Active Pattern Sunday Night through Tuesday Night. Severe thunderstorms possible each day. - High temperatures well into the 80s, around 10 degrees above normal, through Tuesday. && .DISCUSSION... Issued at 254 PM CDT Sat May 18 2024 19Z surface analysis reveals a modest surface trough stretched from northern Iowa southwest through northwest Missouri into Kansas. Behind the surface boundary, winds are gusting around 20 to 25 mph. Visible satellite reveals some minor cu development in southwest Iowa toward S. Joe and into northeast Kansas. The latest runs of the HRRR have been less bullish with convective development along this boundary as it advances toward the KC Metro and lower Missouri Valley through the late afternoon and early evening. Forecast soundings suggest a rather deep, 5 to 6kft, mixing layer and rather weak wind profiles. Elevated instability will be sufficient, but given the lack of supportive shear, organized updrafts are looking difficult to come by. Regardless, will keep a low PoP mention going through the evening, with the best window between 5 and 8 PM CDT. If any one updraft can tap into the 1000 to 1500 J/Kg MLCAPE, an isolated bout of severe hail or wind cannot be ruled out. Positively tilted mid-level ridging will continue to strengthen aloft across the region through Sunday morning. Overnight tonight, a complex of thunderstorms is expected to develop with support from a weak, open, H500 short wave trough traversing the larger flow pattern along the northern Kansas and southern Nebraska. Through sunrise, whatever remains of this activity will slide begin to slide across northwestern Missouri and continue east through the day along the MO/IA border. Most precipitation chances will exist along and north of the US-36 corridor during the day. South of this activity, modest return flow will persist ahead of a developing surface trough over the western High Plains. Low to mid 60s surface dew points will develop through the late afternoon. Convection is forecast to fire in central Kansas by mid-afternoon near the triple point, with convection growing upscale into a line or broken line of storms as it moves into far eastern Kansas and western Missouri by late in the evening. Some of this line may be strong to severe as it arrives with damaging winds and hail and flash flooding the primary concerns. Storms are expected to lower in intensity as they move east through early Monday morning, with localized flooding a lingering concern. Monday, lingering showers and thunder may be ongoing across portions of the area, likely ending through midday. At the same time, a long wave trough will strengthen across the western CONUS, with another surface trough developing over the western High Plains of CO/KS. With better access to return flow and a more robust synoptic pattern setting up to the west, recovery is expected in the wake of any lingering precipitation in the morning. The good news for now is that the better focus forcing looks to be in western Nebraska to central Kansas, nearer the low center and focused along the warm front, which the latest mid-range guidance has a bit farther north. However, as the low level jet increases through the evening and the region well within the warm sector, some organized convection is expected and could result in some strong to severe updrafts. Tuesday could be the more significant day for severe convection across the region. It goes without saying, but any morning precipitation would influence recovery, but with a more negative tilt to the H500 shortwave trough ejecting across Nebraska in the morning, strong WAA will persist, with ample recovery more than likely ahead of the surface trough as it pushes east into the afternoon. With steep mid-level lapse rates and surface dew points nearing 70 F, MLCAPE between 1500 and 2500 is possible. However, forecast soundings through the afternoon from the NAM suggest a sizable capping inversion and given 700mb southwest flow, it`s likely the inversion will hold off initiation until the arrival of the surface front. Latest guidance has the line lighting up around 00Z from northwest Missouri southward toward the KC Metro. Timing of the boundaries arrival will be key and a primary forecast focus as step through the next two days. 0-6km shear orientation suggests initial convection would be isolated, supercellular in nature, but quickly developing into a line as the surface front surges south- southeast through the evening. Damaging winds and hail and a tornado or two cannot be ruled out with storms Tuesday evening/night. Precipitation will clear out through Wednesday with surface ridging briefly holding on before another trough arrives into Friday from the west. && .AVIATION /06Z TAFS THROUGH 06Z MONDAY/... Issued at 1218 AM CDT Sun May 19 2024 Cold front has moved through the area, and will starting moving back northward this afternoon which may result in a shifting wind direction. However winds will generally be under 10 kts for most of the afternoon. Expecting some cumulus development this afternoon. Will be watching for thunderstorm cluster out of Central Kansas to move into the area after 00z this evening that could bring some showers and thunderstorms. However, there is still uncertainty as to how strong it will be as it crosses the Missouri Kansas stateline. For now, will just place VCSH in the TAFs toward the end of the period, and will reassess in subsequent TAF issuances. && .EAX WATCHES/WARNINGS/ADVISORIES... MO...None. KS...None. && $$ DISCUSSION...Kurtz AVIATION...Krull