Area Forecast Discussion
Issued by NWS Topeka, KS
Issued by NWS Topeka, KS
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779 FXUS63 KTOP 231955 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 255 PM CDT Thu May 23 2024 .KEY MESSAGES... -There is a slight chance for an isolated storm this afternoon. If a storm can form, it could reach severe limits, with all modes possible. -Chances for storms are higher overnight along a cold front. Damaging wind appears to be the main threat. -Another round of active weather is then expected Saturday afternoon and evening. && .DISCUSSION... Issued at 250 PM CDT Thu May 23 2024 Southerly return flow is advecting warmer temperatures and higher dew points into eastern KS this afternoon, making the air mass increasingly buoyant. Surface obs show dew points around 70 degrees near the KS/OK state line and mid 60s creeping into east-central KS as of 18Z. Two areas of low pressure are evident, one over South Dakota and another over eastern Colorado. A dryline extends southward from the Colorado low across southwestern KS and into the Texas panhandle. Water vapor imagery shows mid level cyclonic rotation located over the WY/MT state line. This afternoon and evening, there is just a slight chance for isolated thunderstorm development in the warm sector. Confidence remains low given lack of upper support and soundings showing a fairly dry column. Have kept chances around 20 percent to account for some weak warm front and isentropic related ascent. If a storm does develop -- and again chances are low -- the very unstable air mass will support severe weather. DCAPE values above 1000 J/kg would support a damaging wind risk, deep layer shear around 40 kts would support a hail threat and 0-3km SRH above 150 m2/s2 would support a tornado risk. A better chance for thunderstorms still exists after midnight along a cold front moving through eastern KS. The better large scale forcing will be north of the area, but thinking is that there will be enough convergence along the boundary, combined with a 40-60 kt LLJ, to get storms going as the boundary advances into north-central KS. Damaging wind appears to be the main threat with the line of storms. Storms should exit into MO by around 14Z Friday. Surface ridging takes over by Friday afternoon, making for pleasant conditions at that point. Attention then turns to the next system, set to bring active weather back to the area early in the holiday weekend. Another warm front is expected to lift northward through the area on Saturday as lee cyclogenesis occurs ahead of an approaching mid level trough. Instability could build quite rapidly in the warm sector during the afternoon hours. Shear also looks impressive with various models hinting at around 50 kts of bulk shear and some veering of winds in the low levels. Coverage of storm is less certain, but all modes of severe weather appear possible at this time during the late afternoon and evening hours. Calmer conditions then looks likely for the rest of the holiday weekend and into the middle of next week with northwest flow becoming more dominate aloft. && .AVIATION /18Z TAFS THROUGH 18Z FRIDAY/... Issued at 1231 PM CDT Thu May 23 2024 A cold front will move through the area tonight, bringing a chance for storms and possible MVFR conditions for a few hours. This afternoon, VFR prevails with winds increasing slightly from the south-southeast. A LLJ then strengthens tonight, which could create some surface gusts near 25 kts. Thunderstorms become possible near a cold front after 09Z at KMHK and after 10Z at KTOP/KFOE. The front should move through quickly, so only have TS mentioned for a brief period. Winds will turn to a northwesterly direction behind the surface boundary Friday morning. && .TOP WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Teefey AVIATION...Teefey