Area Forecast Discussion
Issued by NWS San Angelo, TX
Issued by NWS San Angelo, TX
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667 FXUS64 KSJT 301920 AFDSJT Area Forecast Discussion National Weather Service San Angelo TX 220 PM CDT Tue Apr 30 2024 ...New SHORT TERM... .SHORT TERM... (This evening through Wednesday) Issued at 218 PM CDT Tue Apr 30 2024 A little bit of an all or nothing forecast for later this afternoon and evening across West Central Texas. Unstable air mass with CAPE values climbing above 2500 J/KG, but a weak cap still in place. Not much of a convective focus other than relatively weak convergence along a developing dryline. And not a lot of upper level support with weak ridging in the mid and upper levels. All this means is that storm initiation is a question, but if a storm can develop that storm may be enough to weaken the cap and allow for storms to develop in a small convective cluster. Which is exactly what several of the high resolution CAMs are showing, while other models are showing little convection and isolated storms at best. Will go with a little bit of a consensus and expand the area of storms to cover more of the Concho Valley and Heartland, with a little higher POPs across the Big Country where CAMs are showing a little more possibility of one of those convective clusters. Given the instability, there is a potential for a few of these storms to reach severe levels, although only very modest shear values may make it more difficult for these storms to not outflow themselves and may put a limit on just how severe the storms may be. SPC has a marginal risk and that seems like a perfectly good forecast. Not going to talk a lot about the severe weather potential for tomorrow. Will let the long term AFD handle it since most of it will be after 00Z. But will say that the air mass doesn`t change very much, but given a much better defines shortwave approaching to provide better shear and a sharper boundary, storms look more likely. && .LONG TERM... (Wednesday night through next Tuesday) Issued at 212 PM CDT Tue Apr 30 2024 The dryline is forecast to remain well west of our area on Wednesday, only advancing east into the Trans-Pecos region and Permian Basin. East of the dryline, good instability will develop, with SBCAPE values of 3K to 4K J/KG. Shear will be modest, with 0-6 KM Bulk Shear values of 30 to 35 knots. A weak upper level shortwave trough is forecast to track across the region late Wednesday, which should result in the development of showers and thunderstorms along the dryline to our west. This activity will then track east across much of the forecast area through the evening hours. A few strong to severe thunderstorms are possible, with large hail and damaging winds being the main hazards, although a tornado is also possible. Initially storms should be discrete with supercells most likely, but as the activity advances east, the cells might merge in to one or more linear complexes. Rainfall amounts will likely range between 1/4 and 1/2 inch of rainfall, but amounts over 1 inch are possible in any of the more intense storms. At this point, the highest rain chances look to be across our eastern counties, where a more linear mode in convection is expected versus our western counties where more discrete cells are likely. On Thursday, a dryline is forecast to advance east into our central counties by mid to late afternoon. Meanwhile, a cold front will move into the Big Country during the morning hours, then approach central portions of the area by mid to late afternoon. Isolated to scattered showers and thunderstorms will be possible during the afternoon and evening hours, for those areas south of the front and east of the dryline. This will confine PoPs to mainly our eastern counties. Cooler temperatures and gusty north winds will filter in behind the front. Expect overnight lows in the 60s. Highs on Friday will be a few degrees cooler, in the upper 70s to mid 80s across the Big Country to the mid to upper 80s elsewhere. Slightly cooler temperatures are expected this Friday into the weekend, with highs mainly in the 80s. PoPs this weekend continue to be somewhat uncertain and will depend on exactly where the front stalls and eventually how far north it lifts. At this point, PoPs were kept mainly in the chance category, with the higher PoPs across the Big Country. These may need to be adjusted on future shifts once higher confidence is reached. && .AVIATION... (18Z TAFS) Issued at 1213 PM CDT Tue Apr 30 2024 The MVFR cigs of the morning have largely lifted and are starting to break up some, with most areas likely to see VFR conditions for the remainder of the afternoon and evening. More low clouds are likely to return overnight and VFR conditions will prevail again by sunrise Wednesday morning. Latest CAMs continue to show some support for some convection this evening, although they vary widely in coverage. Right now it looks like the best chances may be near KABI for a few hours around sunset, with much more isolated activity farther south. Will include a tstm mention up at KABI for a few hours but hold off elsewhere until the chances look better. && .PRELIMINARY POINT TEMPS/POPS... Abilene 67 86 65 90 / 30 30 70 20 San Angelo 69 89 67 93 / 20 40 60 10 Junction 70 87 69 90 / 0 30 60 30 Brownwood 67 84 67 87 / 10 30 80 40 Sweetwater 68 87 65 91 / 20 40 50 10 Ozona 68 82 67 91 / 10 30 40 10 Brady 69 84 67 86 / 10 30 80 30 && .SJT WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...07 LONG TERM....Daniels AVIATION...07