Area Forecast Discussion
Issued by NWS Topeka, KS
Issued by NWS Topeka, KS
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585 FXUS63 KTOP 251033 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 533 AM CDT Sat May 25 2024 .KEY MESSAGES... - The potential for a higher-end severe weather event remains this evening into early Sunday. Damaging wind gusts, large hail, and a few tornadoes are all possible. - Thunderstorms chances continue through Sunday before drier and quieter conditions are expected Memorial Day through at least Tuesday. && .DISCUSSION... Issued at 350 AM CDT Sat May 25 2024 All is quiet across the region this morning with surface high pressure positioned over the central Plains. A shortwave is progressing east towards the Four Corners and will be the instigator of this evening`s severe weather event. As this wave approaches the Plains through the day, winds become south-southeasterly and a surface low deepens across eastern Colorado and western Kansas. Models continue to vary on the degree of low-level moisture return during the afternoon and evening as a warm front lifts north. Consensus shows dewpoints in the low to upper 60s across northeast Kansas by later this evening (7-9pm) with some low 70 dewpoints across southern Kansas. CAMs are generally in agreement with convective initiation occurring in the 6-8pm timeframe across western and central Kansas as the wave ejects across the area and sufficient moisture makes it into the region. Supercells are likely initially given the robust shear/instability parameter space and have a high probability of producing large to giant hail and damaging wind gusts. The uncertainty surrounding the quality of low-level moisture leads to some questions around the tornado potential especially with northern extent, but low- level hodographs elongating and veering with time during the evening and overnight certainly support tornadoes, perhaps even strong tornadoes, if quality moisture is in place. Storm evolution beyond into the late evening and early morning hours Sunday remains somewhat uncertain, but increased ascent from the passing wave is expected to transition convection to a linear mode. CAMs show a wide range in potential locations of this line of storms, but the most favorable location should be along the nose of the low-level jet which is progged to be somewhere between the Kansas/Oklahoma state line and Interstate 70. Damaging winds of 60-80mph become more of a concern once an MCS develops with a continued tornado threat given the degree of low-level shear. There is a signal for storm motions to become parallel to the boundary as the LLJ continues to pump moisture into the region which would increase the potential for flooding. HREF LPMM precipitation shows the potential for 2-4 inches of rain in a couple hour period if storms can train/back build. Even with the severe event ~18 hours out, uncertainty remains in key aspects of the event including location of strongest storms and timing. Some of these (on the synoptic and mesoscale) will become clearer through the day today, but others (storm scale interactions) will not be known until storms develop. The bottom line is that the environment will be favorable for severe weather this evening and tonight, including the potential for significant severe weather, so stay weather aware and have multiple ways to receive warnings especially at night. The surface low continues its east-southeast progression on Sunday as another trough ejects across the Plains. Steep mid-level lapse rates on the backside of the low lead to MUCAPE of 1000-1500 J/kg with effective shear of 20-30kts. This could lead to the development of strong to severe storms Sunday afternoon capable of producing large hail, but this will be dependent on how convection Sunday morning evolves. Dry conditions are favored for Monday and Tuesday as northwest flow sets up across the Central Plains. A couple of passing perturbations lead to chances for showers and storms Wednesday through Friday, but variability is high this far out. && .AVIATION /06Z TAFS THROUGH 06Z SUNDAY/... Issued at 533 AM CDT Sat May 25 2024 Winds increase from the SSE through the day with gusts of 20-25kts this afternoon and evening. Confidence in storm coverage and timing this evening and overnight remains low, but input VCTS in the most likely timeframe for storms to impact terminals. Large hail, strong wind gusts, and MVFR cigs are possible if storms impact TAF sites. && .TOP WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Flanagan AVIATION...Flanagan