Area Forecast Discussion
Issued by NWS Austin/San Antonio, TX
Issued by NWS Austin/San Antonio, TX
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702 FXUS64 KEWX 211847 AFDEWX Area Forecast Discussion National Weather Service Austin/San Antonio TX 147 PM CDT Sat Sep 21 2024 ...New SHORT TERM, LONG TERM... .SHORT TERM... (Tonight through Sunday night) Issued at 108 PM CDT Sat Sep 21 2024 Daytime mixing will continue to scatter out low clouds and produce partly cloudy, and then mostly clear, skies late this afternoon into early evening. The general pattern of low-level clouds returning by late evening and persisting overnight into the next morning will continue, but lower boundary layer humidity should result in less fog along and east of I-35/I-37 Sunday morning. The approach of a longwave trough and near-surface cold front will bring sufficient lift for showers and a few thunderstorms across the northern Rio Grande Plains, Edwards Plateau, and western Hill Country Sunday evening into the overnight hours. Rainfall will be spotty and average 1/10 inch or less. Daytime temperatures will be 2- 4F cooler across the entire area on Sunday because of additional cloudcover. && .LONG TERM... (Monday through Saturday) Issued at 108 PM CDT Sat Sep 21 2024 A much-needed pattern change appears to be on the way for the last full week of September. A mid-level trough will gradually erode the 500mb high that`s been keeping things hot and dry for the last couple of weeks in South Central Texas. On Monday, a cold front will start sliding southward into the Hill Country and Southern Edwards Plateau. Model trends continue to bring this front to a halt over the Hill Country late Monday and it is unlikely to make much progress until late Tuesday per the latest Canadian/ECMWF runs. The GFS is not as aggressive with forcing the boundary south, but the trend is your friend, and this time of year usually calls for frontal boundaries sliding further south the global model guidance usually suggests. In any matter, cooler temperatures, ample cloud cover, and an overrunning regime should result in scattered showers and the occasional isolated thunderstorm Monday afternoon, Tuesday afternoon, and again Wednesday afternoon and evening. By Thursday, the mid-level trough should start to finally shift eastward into the Ohio Valley, resulting in a drying trend for the region. Dewpoints will be much more manageable, as slightly cooler, more so drier air, will work its way south with the frontal boundary. Expect more seasonable high and low temperatures in the 80s Wednesday, with mid to upper 80s and perhaps some lower 90s Thursday-Saturday. && .AVIATION... (18Z TAFS) Issued at 1227 PM CDT Sat Sep 21 2024 Expect remaining MVFR to lift and thin to VFR by 20Z at all sites. South to Southeasterly flow will persist at all sites through the forecast period, with gusts to 20-22 KT at times for KAUS and KDRT this afternoon. Look for CIGS to develop and fall starting around 06-09Z, with MVFR CIGS expected at all locations from 09-15Z. There may be some BCFG from 10-15Z, but that is not expected to impact operations. CIGS will lift but be very slow to become SCT on Sunday. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 75 96 74 93 / 0 0 10 10 Austin Bergstrom Intl Airport 73 95 73 93 / 0 0 0 10 New Braunfels Muni Airport 74 96 73 95 / 0 0 0 10 Burnet Muni Airport 73 92 71 87 / 0 0 20 20 Del Rio Intl Airport 79 95 76 91 / 10 0 30 40 Georgetown Muni Airport 73 94 73 90 / 0 0 10 10 Hondo Muni Airport 74 94 72 93 / 0 0 10 10 San Marcos Muni Airport 73 94 71 93 / 0 0 0 10 La Grange - Fayette Regional 73 94 72 93 / 0 0 0 10 San Antonio Intl Airport 76 94 75 93 / 0 0 10 10 Stinson Muni Airport 76 95 74 96 / 0 0 0 10 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Short-Term...Zeitler Long-Term...MMM Aviation...Zeitler