Area Forecast Discussion
Issued by NWS Austin/San Antonio, TX
Issued by NWS Austin/San Antonio, TX
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789 FXUS64 KEWX 141703 AFDEWX Area Forecast Discussion National Weather Service Austin/San Antonio TX 1203 PM CDT Sun Jul 14 2024 ...New AVIATION... .SHORT TERM... (Today through Monday) Issued at 215 AM CDT Sun Jul 14 2024 A broad, inverted upper trough will remain to the west and northwest of the region through early this week. Some weak lift associated with this feature may aid in the development of some light showers out west across the Rio Grande plains today. In addition, some isolated showers and thunderstorms will remain in the forecast for this afternoon across portions of the coastal plains and Highway 77 corridor. We should see partly to mostly cloudy skies today and this will help keep temperatures at or just slightly below climatological levels for mid July. On Monday the pattern remains fairly consistent across the region, although a slight decrease in moisture levels is anticipated. While we could see some low chances for afternoon convection out west along the Rio Grande and over the coastal plains, the latest hi-res models do not show much promise. For now, we will keep the forecast dry on Monday and monitor subsequent model runs. A decrease in cloud cover should be enough to push highs back to a degree or two above normal. && .LONG TERM... (Monday night through Saturday) Issued at 218 AM CDT Sun Jul 14 2024 Models are trending more stable in the early to middle part of the week, after the deterministic runs a day or two ago suggested a more unstable shear pattern over West and South Central TX through around Wednesday. The more stable pattern features an eastward surge of the Rocky Mountain upper ridge into Oklahoma Tuesday. South of this upper ridge, weak upper troughing remains mainly over Mexico, but some pooled moisture might still allow for a weak convective cell or two down in the SW corner of the CWA. More likely, we`ll see a couple days of additional dry weather, while low level humidities remain elevated enough to perk up the heat index into the 100 to 106 range, and perhaps a degree or two higher in a few spots. This trend is fairly recent, but does agree with some of the model scenarios from last week for this time-frame. For now we`ll keep out the elevated heat index messaging as this is probably our usual peak period for such weather. However, we may begin messaging the elevated heat potential in the next forecast package or two should the model trends promote any further mid-week heating. A more consistent signal has been promoted by the model consensus with less of a yo-yo picture for late next week--a return of northerly flow aloft. In the latest runs both the ECM and GFS signaled less ridge weakness over the Rio Grande region but a southward pivot of the upper ridge axis that previously extended to the east into OK/North TX. This opens up an increasingly fast return to unstable northerly flow aloft and possibly an earlier onset of the associated weak cold front previously projected for Friday. Thursday may start off hot with some elevated heat indices, but could finish with some outflow boundaries, pushing south into the area with the beginnings of the weak front arriving into the northern CWA by the evening. We took a degree of two off the top of the NBM Thursday`s MaxT over the northern Hill Country, but the more noticeable temperature trend should still be seen for Friday. The milder and more convectively unstable pattern should continue through next weekend with typically vaguely described 20-40 percent chance type PoPs for each day. && .AVIATION... (18Z TAFS) Issued at 1202 PM CDT Sun Jul 14 2024 VFR conditions will prevail the rest of today and most likely into tomorrow. There remains a chance for some patchy MVFR ceilings to develop, but with mid to high cloud cover remaining over much of the forecast area this may keep low ceilings isolated. For now have only included SCT015 groups for this possibility. Southerly to southeasterly wind continues, with breezy afternoon winds in the west today and tomorrow. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 96 76 99 74 / 0 0 0 0 Austin Bergstrom Intl Airport 94 75 97 73 / 10 0 0 0 New Braunfels Muni Airport 94 75 97 72 / 10 0 0 0 Burnet Muni Airport 95 74 97 73 / 0 0 0 0 Del Rio Intl Airport 95 79 99 79 / 20 10 10 0 Georgetown Muni Airport 95 74 97 73 / 0 0 0 0 Hondo Muni Airport 93 75 97 73 / 10 0 0 0 San Marcos Muni Airport 94 73 96 71 / 10 0 0 0 La Grange - Fayette Regional 92 75 94 74 / 20 10 0 0 San Antonio Intl Airport 94 76 97 74 / 10 0 0 0 Stinson Muni Airport 95 77 97 75 / 10 0 0 0 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Short-Term...Platt Long-Term...18 Aviation...27