Area Forecast Discussion
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Issued by NWS
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960 FXUS64 KLUB 191936 AFDLUB Area Forecast Discussion National Weather Service Lubbock TX 236 PM CDT Thu Sep 19 2024 ...New SHORT TERM, LONG TERM... .SHORT TERM... (This evening through Friday) Issued at 232 PM CDT Thu Sep 19 2024 Water vapor channel imagery highlights a broad upper ridge centered over northern Mexico gradually expanding northward early this afternoon, resulting in a continued lack of any features of interest aloft over West Texas. Surface moisture remains relatively impressive over most of our area, especially off the Caprock where dewpoints in the mid to upper 60s at 19z, and this has allowed development of a small cumulus field over the southeastern TX Panhandle. We still expect convective growth today to be constrained by a dramatic increase in mid and upper level subsidence associated with the expansion of aforementioned ridging aloft. A few very isolated small showers are certainly possible through the rest of the afternoon given strong heating and the moist low levels, but will still run with sub-mentionable PoPs given the expected low coverage and limited duration with convection fading quickly after sunset and another quiet and relatively humid night expected tonight. On Friday, the closed upper low off the CA coast will begin to accelerate eastward with the upper ridge progged to contract southeastward compared to today. A few showers may sneak into the far southwestern TX Panhandle Friday afternoon and evening, but for now it still looks like most precipitation will stay west of the TX/NM state line on Friday in closer proximity to more robust midlevel moisture. Given only very modest height falls on Friday, temperatures will be similar to today with highs ranging from the low 90s near the TX/NM state line to the low 100s across the far SE TX Panhandle. && .LONG TERM... (Friday night through next Wednesday) Issued at 232 PM CDT Thu Sep 19 2024 An active weather pattern is still in the cards for this weekend representing more of a spring like pattern. A strong closed low affecting the area this weekend was currently moving southeastward along the California coastline. The center of this system will make it as far south as 33N before ejecting out to the northeast on Friday. During our time of interest on Saturday, this system will be moving northeastward around the four-corners. The bulk of the lift from this system will be ejecting out over Colorado into the Texas Panhandle with the tail end of large scale ascent into West Texas. Models prog a 100kt or so jet streak over northeastern New Mexico on Saturday afternoon spreading strong wind divergence aloft over the area from mid to late afternoon. A dryline will tighten up in the afternoon but will likely remain over eastern New Mexico and not mix eastward given the upper low position near the four corners. Therefore, the best low level convergence will remain over eastern New Mexico through the afternoon. This will also be the preferred point of convective initiation as a strong axis of higher theta-e air surges northward along and east of the dryline. The axis of highest instability will therefore be in eastern New Mexico close to the Texas/New Mexico state line. Current values from models indicate between 1000 and 1500 J/kg of mixed layer CAPE becoming uncapped by mid-afternoon just as the large scale ascent spreads over the region. Instability will weaken farther to the east which brings some uncertainty in how far east the convective activity will reach. Given the amount of instability expected along with increasing deep layer shear, storms will have the potential to become severe with damaging winds as the primary threat and marginally severe hail and heavy rain/flooding as secondary threats. A cold front will be positioned to our north on Saturday and will make its way southward on Sunday. Latest model solutions have slowed the front down pushing it through mostly during the afternoon. Weak large scale ascent will remain overhead on Sunday as the upper low pushes through Colorado. The dryline will likely make some headway eastward ahead of the front but should still result in warm juicy air in the warm sector. Additional thunderstorms appear possible ahead of the front and east of the dryline but the position of the front bring doubts into how far north and west the chances of thunder will extend. However, the best chances will most certainly be across the Rolling Plains. Thunder chances will eventually come to an end once the front clears the area late Sunday into early Monday morning. Rain and thunderstorm chances will be renewed by Tuesday as the next short wave trough dives southward through the Rockies. && .AVIATION... (18Z TAFS) Issued at 1225 PM CDT Thu Sep 19 2024 VFR will continue at all sites through this TAF period. && .LUB WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...30 LONG TERM....01 AVIATION...30