Sunrise 6:18 AM   Sunset 8:09 PM Moonrise 12:20 AM   Moonset 9:17 AM

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FXUS63 KEAX 290759 AFDEAX

Area Forecast Discussion National Weather Service Kansas City/Pleasant Hill MO 259 AM CDT Mon Apr 29 2024

KEY MESSAGES

- Quiet, seasonal weather conditions for Monday and Monday night.

- Strong to severe storms possible Tuesday afternoon and evening.

- Active weather pattern continues through at least Thursday night, with a lull possible Friday into Saturday. This could aggravate ongoing flooding concerns across the area.

DISCUSSION
Issued at 259 AM CDT Mon Apr 29 2024

Surface analysis at 2 am shows the cold front splitting the forecast area generally north to south, east of I-35. This front will continue to move east and should be east of the forecast area by 12Z. There will be a few showers and possibly a thunderstorm along the front as it moves east in the predawn hours. A cooler and less humid airmass will move into the region behind the front and give the area seasonal temperatures with dry conditions. Highs today should range from the upper 60s across northern MO to the middle 70s south of Highway 50.

This dry and seasonal weather will be short-lived as the surface shifts into the Southeast by Tuesday afternoon. With lee troughing in the High Plains, a tighter pressure gradient develops across the central to eastern Plains. This allows for southerly flow to develop and moisture, which wasn't displaced that far south to begin with, surges northward. In the mid and upper-levels, a strong shortwave trough will eject into the central Plains and push a cold front eastward across Nebraska and Kansas. This helps tighten the pressure gradient further and by the afternoon we should be seeing wind gusts of 30-35 mph across eastern KS and western MO. The return of moisture and temperatures climbing into the lower to middle 80s will help build modest instability across eastern KS and western MO.
HRRR probabilities show a 70+ chance of greater than 1000 J/kg of surface based CAPE. These percentages drop off at 2000 J/kg so eastern KS and western MO will likely end up in the 1000-2000 J/kg range for SBCAPE as the front is moving into the area.
There's also a high probability of effective shear between 30-40 kts with it's orientation nearly orthogonal to the cold front.
This will favor the potential for supercells with large hail, damaging winds and a tornado or two. The greatest area looks to be from far northwest MO in eastern KS and west central MO.

With the strongest forcing associated with the shortwave trough passing north of the area, the southward push of the front dies and the front stalls in the vicinity of the forecast area. Models vary significantly with this but the consensus is generally in our south or possibly just south of the forecast area. As the next shortwave digs into the Four-Corners region, southerly flow increases and pushes the front north again as a warm front. Convection may be ongoing Wednesday as the warm front lifts into Northern MO or just north of the area. This warm and moist low-level pattern leads to moderate instability with the area likely to see 2000-3000 J/kg of CAPE by Wednesday afternoon. This could be lower if convection and cloud cover are more widespread. Wednesday evening, a strong low- level jet develops and noses into the boundary. As a result, the coverage of showers and storms become more widespread after sunset Wednesday evening. The focus of this round of convection looks to be across northwestern to northern MO, in the vicinity of the front.

For Thursday, a strong shortwave trough will move into the northern Plains and push the front southward as a cold front.
Instability will be more uncertain depending on how the Wednesday night/ Thursday AM convection evolves. But if the area does recover from that earlier activity, we should be the right-rear quadrant of the upper jet with stronger mid to upper- level flow leading to stronger shear. So there is a more conditional risk of severe weather Thursday depending on how the area destabilizes from the earlier convection.

Similar to today, a cooler and drier airmass moves into the region Friday. That should lead to a period of quieter weather before the moisture recovers. Models show the high shifting into the Southeast with southerly flow returning, allowing moisture to return to the area late in the weekend and into next week. Models vary on the pattern more for this time frame so confidence is lower on any one day being more likely than another for rainfall. This results in a broad brushing of lower PoPs for Sunday and Monday.

AVIATION /00Z TAFS THROUGH 00Z TUESDAY/
Issued at 1155 PM CDT Sun Apr 28 2024

A cold front moved through the terminals in the last 1-2 hours.
This will lead to light westerly winds and drier air moving into eastern KS and western MO, which will result in VFR conditions through the forecast.

EAX WATCHES/WARNINGS/ADVISORIES
MO...None.
KS...None.

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