Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO
Issued by NWS Kansas City/Pleasant Hill, MO
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108 FXUS63 KEAX 181757 AFDEAX Area Forecast Discussion National Weather Service Kansas City/Pleasant Hill MO 1257 PM CDT Wed Sep 18 2024 .KEY MESSAGES... - Strong, potentially severe storms possible Thursday. - Well above normal temperatures expected through Friday. Temperatures roughly 10-15 degrees above normal across the area. - Widespread rain still likely this weekend. && .DISCUSSION... Issued at 303 AM CDT Wed Sep 18 2024 Upper-level ridging, being compressed between a deep western trough and a closed upper low over the eastern CONUS, will lead to unseasonably warm conditions today. 1000-850mb thickness values increase substantially through the day as a result of the upper ridging and strong warm adevection. This should lead to temperatures near 90 this afternoon, ~1-2 degrees warmer than Tuesday. Thursday looks even warmer as the upper ridging strengthens and the thickness values increase in response. Highs Thursday are likely to be in the lower to potentially middle 90s. These hot temperatures will occur with increasing moisture into the area as strong warm and moist advection brings mid to upper 60 degree dewpoints into the area. That heat and humidity will lead to a moderately unstable airmass across the area with SBCAPE values ranging from about 700-800 J/kg at the 25th percentile of guidance to 1500-1600 J/kg at the 75th percentile of guidance. With increasing flow aloft, deep-layer bulk shear should range from about 28kts to 35kts across northern MO. This combination will support strong to severe storms. Mean convective inhibition of roughly -50 to -75 J/kg will be hard to overcome during the day. Given this, it looks more likely storms will develop during the evening as a cold front begins to move into the area. Ensemble guidance shows this well with relatively low probabilities during the afternoon and then much higher probabilities after 00Z, especially across northern MO. Lapse rates don`t look particularly steep aloft so the threat of hail will mainly be a result of potential supercell structures, given the shear. Models also show fairly strong low-level curvature to hodographs across northern MO, suggesting there is some potential for a tornado. Otherwise, strong winds look like the most likely hazard. For the weekend, the front that moves through Thursday night/ Friday, will stall in the vicinity of the forecast area. This will lead to the potential for widespread and much needed rainfall. Generally, it looks more likely that north of the river and across far northwestern MO will see the heaviest rainfall. This is where the highest probabilities of exceeding various rainfall amounts reside. Our current forecast shows widespread 1"+ amounts across most of the forecast area, with 2-3" amounts in far northwestern MO/ and northeastern KS. There is even a small chance (about 10-15%) that northwestern MO exceeds 3" with this event. If these rain totals come to fruition, it will help greatly with the worsening drought conditions across the area. Speaking of drought, this is the 2nd driest first 17 days of September for Kansas City on record. Records for September date back to 1888. && .AVIATION /18Z TAFS THROUGH 18Z THURSDAY/... Issued at 1218 PM CDT Wed Sep 18 2024 VFR conditions are expected to persist through the period. Southerly winds between 10 and 13 knots with occasional gusts up to 20 knots should continue this afternoon before relaxing to 8 knots or less by this evening. && .EAX WATCHES/WARNINGS/ADVISORIES... MO...None. KS...None. && $$ DISCUSSION...CDB AVIATION...BMW