209 FXUS64 KLUB 200530 AFDLUB Area Forecast Discussion National Weather Service Lubbock TX 1230 AM CDT Fri Sep 20 2019 .AVIATION... MVFR in place at KLBB and KCDS. Expecting ceilings to lower at KPVW at any moment. Then MVFR ceiling will stick around through the early morning followed by VFR during the early afternoon. Another round of afternoon TSRA is expected at all terminals later today. Timing of this activity is still uncertain so for now will leave it out of the forecast. && .PREV DISCUSSION... /issued 911 PM CDT Thu Sep 19 2019/ UPDATE... MCS moving across the eastern Panhandle has led to an adjustment to raise precip chances across the northeastern counties. Elsewhere, could see some additional convection try to form along and behind the outflow boundary. Otherwise, models have backed off chances for additional precipitation for the remainder of the night. Still, elevated instability and lingering mid level moisture will lead to prudence of keeping 20-30 percent PoPs in the forecast for the overnight hours. PREV DISCUSSION... /issued 627 PM CDT Thu Sep 19 2019/ AVIATION... TS will primarily stay to the north and northwest of the terminals this evening, but close enough of a threat at KLBB and KPVW to keep a mention going for the first two to three hours of the forecast. Some indication that there will be low clouds with MVFR ceilings Friday morning, but confidence is low right now given lack of consensus. Will maintain VFR forecast conditions at this time. PREV DISCUSSION... /issued 315 PM CDT Thu Sep 19 2019/ DISCUSSION... Thunderstorm chances over the next few days, including the risk of a couple strong to severe storms capable of producing locally heavy rainfall, highlight this afternoon's forecast package. A broad western trough will continue to advance steadily eastward the next several days, with a portion of the trough lifting out across the central/northern High Plains Saturday, and the remaining piece following on Sunday. In advance of the troughiness, unsettled southwesterly flow aloft will persist over West Texas, along with a gradual increase in deep layer shear. In addition, moisture levels will rise, helping support moderate instability at times. The combination of the increased wind shear and instability will support greater coverage and intensity of storms...at least around peak heating this afternoon, tomorrow and Saturday (and perhaps Sunday). Not to be forgotten, several embedded weak disturbances, including one this afternoon/evening and perhaps another grazing the region late tonight (well after midnight) will aid in thunderstorm development. In the short term, we have already seen the greatest coverage of storms form near a surface trough stretching from the western Texas Panhandle into east-central New Mexico, with more isolated activity forming along a couple of residual boundaries from the South Plains into the Permian Basin. This activity will move eastward/northeastward through the evening hours. A few of these storms could become strong to marginal severe given the modest instability and marginal wind shear in place, before generally fading mid-late evening. However, we could see another round of convection attempt to move into the western counties toward Friday morning, associated with the next upper level disturbance. Beyond that, a good fetch of mid-upper level moisture from the tropical activity in the eastern Pacific will continue to stream over the region through much of the weekend. This moisture/instability, combined with the unsettled southwest flow aloft, will keep occasional storm chances (some which could be strong/severe) in the forecast. However, the details on exactly how thing play out will depend on previous day's convection and timing of subtle upper level disturbances, both which will have to be resolved in the shorter term. Until then, we have maintained solid rain/storm chances through the weekend. By late weekend, we may see a brief bout of shortwave ridging, but a weak cold front may also sag through the Panhandle, and perhaps into the South Plains, which could provide a focus for additional storm chances. There may be a bit of a brief lull in precipitation chances early Monday, associated with the progressive shortwave ridging. However, eyes will then be fixed on how the next storm system, likely a closed low, evolves across the west. NWP continue to struggle on if/where the low will become cutoff, varying from Arizona to somewhere closer by. Obviously, this will have a big influence on weather impacts locally. For now, we have maintained 20-30% PoPs at the end of the forecast. && .LUB WATCHES/WARNINGS/ADVISORIES... None. && $$ 28/99/28