####018004174#### ACUS01 KWNS 251232 SWODY1 SPC AC 251231 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0731 AM CDT Thu Apr 25 2024 Valid 251300Z - 261200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS EVENING ACROSS WESTERN KS AND TONIGHT ACROSS NORTHWEST TX INTO CENTRAL OK... ...SUMMARY... Very large hail up to 3 inches in diameter and a strong tornado or two will be possible this evening across western Kansas. Large hail up to 2.5 inches in diameter, damaging winds to 70 mph and a few tornadoes will be possible tonight from northwest Texas into central Oklahoma. ...Synopsis... A midlevel shortwave trough and associated 70 kt jet will eject northeastward toward western KS by late tonight and Friday morning. An associated lee cyclone is expected to deepen this afternoon across northeast CO, with a sharpening dryline arcing to its south across western KS and the TX/OK Panhandles. Farther east, a warm front will continue to move northward from OK into KS, though northward progress of the front will be slowed by elevated convection (posing an isolated large hail threat) that will reinforce the cool side of the boundary during the day. A somewhat bimodal threat distribution is expected - the warm sector in western KS and a second corridor overnight from northwest TX into OK. ...Western KS this afternoon/evening... An unstable warm sector will be present through this evening, with boundary-layer dewpoints in the 60s beneath steep midlevel lapse rates. The base of the elevated mixed layer will be relatively warm, suggesting the need for surface temperatures into the 80s on the immediate moist side of the dryline. The better potential for storm development this afternoon will be across western KS, where dryline parcel residence times will be longer and in closer proximity to the left-exit region of the approaching mid-upper jet. The initial dryline storms will likely become supercells capable of producing very large hail of 2-3 inches in diameter, and these storms could continue northeastward as elevated supercells atop the warm front. The potential for a strong tornado or two will increase this evening as the storms encounter richer low-level moisture and increasing low-level shear. However, the window of opportunity will not be particularly large given the presence of a rain-reinforced front to the northeast and increasing convective inhibition by late evening. ...Northwest TX into OK overnight... A general consensus of most overnight forecast guidance suggests a southern corridor of greater hail/wind threat starting early tonight just off the Caprock and then spreading northeastward over northwest TX into southwest/central OK early Friday morning. Thunderstorm initiation will become more probable by 03-06z in association with cooling/moistening at the base of the elevated mixed layer, coincident with the beginning of eastward movement of the dryline/Pacific cold front along the trailing influence of the ejecting midlevel trough. Storm mode will likely trend to clusters/line segments while spreading northeastward. Boundary-layer dewpoints approaching the upper 60s beneath steep midlevel lapse rates will contribute to MUCAPE in excess of 2000 J/kg through the overnight hours, which will favor the potential for both large hail (especially with any embedded supercells) and damaging winds of 60-70 mph. A few tornadoes may also occur with embedded circulations as low-level shear increases tonight. ...TX Panhandle/western OK this afternoon/evening... A conditionally favorable environment for supercells with very large hail and tornadoes will exist this afternoon/evening across the eastern TX Panhandle into western OK. The primary uncertainty here will be lingering convective inhibition and substantial uncertainty in storm coverage/location along the dryline. For these reasons, have lowered the overall severe threat, but maintained some conditional significant severe potential. ..Thompson/Kerr.. 04/25/2024 $$