771 FXUS64 KLUB 151737 AFDLUB Area Forecast Discussion National Weather Service Lubbock TX 1237 PM CDT Sat Jun 15 2019 .AVIATION... High-based thunderstorms are expected to develop within a forecast low level convergence zone lying west-southwest of KLBB and KPVW mid to late this afternoon, then move east-northeast near to both sites before passing KCDS as well early evening. Potential thunderstorms appear may become quite strong and the initial high wind risk will transition to both high wind and large hail. But solutions are currently trending down on projected coverage so uncertain if we will see more than isolated storms or possibly just morphing into a single convective system about the time it could be in the KCDS vicinity. Still uncertainties, but these chances are connected to a short-wave disturbance passing just to the north with fairly well anticipated lift. So we have added a mention of at least VCTS and tempo wind gusts for now. May have to add more later. VFR will dominate late evening into Sunday morning with a potential MVFR cloud layer probably staying just south of KCDS early Sunday and east of KLBB. RMcQueen && .PREV DISCUSSION... /issued 636 AM CDT Sat Jun 15 2019/ AVIATION... Cold front will be impacting KLBB and KPVW by mid-morning, but strongest winds will occur as winds are turning from southwest to northwest. After FROPA, winds relax quite a bit. FROPA at KCDS may occur later this afternoon, but models still do not agree on this. Storms are expected to break out along a dryline this afternoon and evening, impacting KLBB and KPVW first, and not reaching KCDS until sometime this evening. PREV DISCUSSION... /issued 405 AM CDT Sat Jun 15 2019/ DISCUSSION... Isolated convection that was ongoing at the beginning of the night shift has moved east and diminished leaving mild and dry conditions in place early this morning. This will lead nicely into a toasty start to the weekend as a surface trough and diffuse dryline edge eastward through the day today. By peak heating, the deepest moisture should reside off the Caprock where it will likely be capped. However, strong heating and deep mixing west of the dryline coupled with an approaching shortwave trough should be enough to generate isolated to scattered high-based convection across the western and central South Plains by mid-late afternoon. The main threat with this activity will be strong downburst winds and perhaps a few lightning strikes, though measurable precipitation will be at a premium given the hot, dry and deeply mixed boundary layer. Thus, we have kept PoPs down in the 10-20% range on the Caprock this afternoon, but have inserted a severe mention given the risk for strong/severe downbursts. This activity will may try and grow upscale as it moves off the Caprock and encounters the better moisture/instability, though whether or not coverage increases beyond scattered in our FA is unclear, so we have limited PoPs to chance mention over the eastern counties after 00Z. More robust updrafts will likely evolve meaning an increasing hail threat too as the convection begins to ingest the richer moisture. Similar to Friday night, any convection should shift off to the east of the area by mid-late evening. A weak outflow aided front remains on track to dip in from the north early Sunday. This will bring some relief from the heat of today, dropping highs from the 90s today mostly into the 80s tomorrow (or 5 to 10 degrees cooler than today). It does look like the air mass behind the front will largely remained capped Sunday afternoon. The exception may be around the stalling frontal zone which is forecast to be situated somewhere near our far eastern zones. Thus, we have maintained a low thunder mention off the Caprock Sunday afternoon. In fact, a MCS may attempt to develop in response to a mid-level disturbance exiting the eastern Texas Panhandle and if this occurs the tail end of the system could clip our eastern CWA Sunday night. Outflow from the MCS could then reinforce the frontal zone, keeping it somewhere in/near the South Plains again on Monday. Obviously a lot of ifs in the forecast when many of the details (and ultimate storm chances) rely on mesoscale details that evolve from the previous day's convection. Regardless, we have maintained a slim thunder mention on Monday with the potential boundary in/near the area, though it may be capped as a progressive shortwave ridge aloft passes. A better bet will be for the development of an overnight "ridge rider" (originating in northeast New Mexico) that could potentially clip the northern/northeastern FA Monday night. Assuming this happens, another outflow boundary will be set down in the region which could continue to aid in potential future storm development. Details are sketchy at best, but we have maintained low storm chances through Tuesday night with this mind. Eventually, quasi-zonal flow aloft should back more southwesterly downstream of a developing western trough by late week. At a minimum, it looks like temperatures will really heat up late week. If current projections are correct, 850 mb temperatures are forecast to rise in excess of 30C by the end of the week, which could support widespread values near and above 100 degrees. && .LUB WATCHES/WARNINGS/ADVISORIES... None. && $$ 99/99/05