Area Forecast Discussion
Issued by NWS
Issued by NWS
828 FXUS64 KLUB 201100 AFDLUB Area Forecast Discussion National Weather Service Lubbock TX 600 AM CDT Wed Aug 20 2025 ...New AVIATION... .KEY MESSAGES... Issued at 1220 AM CDT Tue Aug 19 2025 - A few showers and thunderstorms are expected to move through the forecast area during the morning and early afternoon hours Wednesday. - A drying trend is forecast to follow Thursday and through this weekend. - Storm chances are forecast to return early next week. && .SHORT TERM... (Today and tonight) Issued at 1201 AM CDT Wed Aug 20 2025 Subtropical ridging has finally settled over the southern Rocky Mountains, with the mid- and high-level anticyclones centered near the AZ/NM state line, as per the 20/00Z objectively analyzed UA charts. The 250 mb anticyclone has enlarged compared to 24 hours when it was centered over the Lowland Deserts of New Mexico, which has caused a weakening in the magnitude of the 250 mb flow over the region. The 20/00Z RAOBs from WFOs AMA and MAF observed 15 kt of flow, whereas last night it was 30-35 kt. The expansion of the 250 mb anticyclone has also shifted the leading edge of the jet streak arcing around the apex of the ridge, causing a wide swath of subsidence to advect over the western High Plains of KS/CO and into W TX. This subsidence layer is well-defined on water-vapor imagery, and will keep thunderstorm chances isolated on the Caprock through the predawn hours Wednesday. Meanwhile, a convectively-augmented vorticity lobe is rotating southward across central OK, and will arrive in the CWA before sunrise and be accompanied by scattered, elevated showers and storms across the Rolling Plains. At the surface, the cold front was analyzed on mesonet data along a line from GUY-HHF-CLK, with a diffuse, pre-frontal trough located to the south of the Red River. The southward progression of the front is convectively-reinforced, and the bulk of the convection will move through the CWA during the predawn hours. Winds were otherwise contaminated by widely-scattered storms across the Caprock, with the light, easterly component persisting in the Rolling Plains. The cold front will continue to weaken as it moves southward through the CWA Wednesday morning, and will dissipate as it moves into the Permian Basin. Light, northeasterly winds will prevail in the wake of the frontolysis, with winds becoming variable by Wednesday evening. The vorticity lobe is expected to rotate into the Permian Basin and Edwards Plateau by the afternoon hours, which will eliminate storm chances across the northern zones by mid-day, with storm chances ending entirely area-wide before sunset Wednesday. As a result of the above, NBM PoPs have been lowered to slight chance/isolated throughout the short-term period, as subsidence aloft will keep coverage in check. High temperatures Wednesday will peak in the lower-middle 90s area-wide, as CAA will be quick to cease as the front dissipates and the airmass maintains its barotropic state under the periphery of the amplifying ridge to the west-northwest. Sincavage && .LONG TERM... (Thursday through Tuesday) Issued at 1201 AM CDT Wed Aug 20 2025 The subtropical ridge will continue to amplify and shift slightly poleward Thursday, becoming centered over the Four Corners region, with geopotential heights rising to 598 dam at its center. However, as mentioned in the previous forecasts, geopotential height tendencies will maintain neutrality over the region given the position of the ridge. Temperatures will remain near seasonal norms Thursday and into the weekend, with storm chances coming to an end as the deep-layer flow aloft becomes increasingly confluent while an expansive surface high noses into the region. Global NWP guidance is in agreement of a cyclonically-breaking wave event to occur over southern Canada following the phasing of two intense 250 mb jet streaks. This will induce substantial geopotential height falls across the northern half of the U.S., and dampen the amplitude of the subtropical ridge over the central Rocky Mountains. Steering flow will, therefore, transition to the northwest, with the CWA forecast to be positioned within the inflection point of the weakening ridge and the longwave troughing digging into the Upper Midwest. By early next week, the subtropical ridge may breakdown entirely, or at least shift farther southward, which would unlock the potential for shortwave perturbations to translate over the region and result in storm chances returning area-wide. Sincavage && .AVIATION... (12Z TAFS) Issued at 535 AM CDT Wed Aug 20 2025 VFR conditions will prevail. Isolated showers and thunderstorms will be possible across the region through late morning and again this evening. Any mention of TS will be kept out of this TAF cycle due to low confidence in timing and coverage. && .LUB WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...09 LONG TERM....09 AVIATION...51