Area Forecast Discussion
Issued by NWS Austin/San Antonio, TX
Issued by NWS Austin/San Antonio, TX
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853 FXUS64 KEWX 011934 AFDEWX Area Forecast Discussion National Weather Service Austin/San Antonio TX 234 PM CDT Sat Jun 1 2024 ...CORRECTED FOR EDITING GLITCH... ...New SHORT TERM, LONG TERM... .SHORT TERM... (Tonight through Sunday night) Issued at 231 PM CDT Sat Jun 1 2024 Radar trends show some isolated convection slowly developing for areas generally along and east of the Interstate 35 corridor. With continued heating, we expect to see additional showers and storms develop over these areas as well as portions of the Hill Country through this afternoon. Severe Thunderstorm Watch #365 for Lavaca and DeWitt counties is ongoing, but may need to be cancelled early if the current radar trends continue. For the late evening into early Sunday morning, the focus for convection will shift westward into the Rio Grande plains and southern Edwards Plateau as a complex of storms is expected to move out of the lower Trans Pecos region. A good amount of the hi-res models and even some support from the global run of the GFS tend to favor a complex of storms moving in, so we have increased rain chances over the NBM. Exactly how far the complex can move across our region is in question, but for now we have added rain chances to the forecast for early tomorrow morning as far east as a Llano to New Braunfels line. Some strong to severe storms are possible, with large hail and damaging winds being the main concerns. For most of the remainder of Sunday, we will keep the forecast dry. The exception being across our north and northeastern counties where models depict some isolated afternoon storms may develop. && .LONG TERM... (Monday through Saturday) Issued at 231 PM CDT Sat Jun 1 2024 Overall stability begins to ramp up Monday, but another shortwave pulls out of the westerlies from the higher terrain late Monday. The deterministic runs show a pretty consistent signal for high plains induced or dry-line storms forming out north/west and moving toward our central counties in the evening. Storm strength and expected coverage is chosen as a split between deterministic consensus and the more conservative NBM. Moisture in soils has not really improved much with the multiple rounds of rain covering mostly over the Hill Country and Central TX. Thus the high dew point environment over our southern counties may be overdone in terms of the models not mixing out the air enough to reflect the appropriate temperature and heat index that should both be increasing for Monday. We think the HI will begin to approach advisory levels but have low confidence, especially given the erratic day-to-day trends we saw with the early season heat wave last week. Height fields aloft appear to climb faster by Tuesday, and this might be the next day a NPW product is warranted. Some light NW flow remains over North TX so some isolated Hill Country convection is noted for Tuesday afternoon. More dominant high amplitude upper ridging builds over TX by Wednesday, so the potential for northerly flow driven storms should decrease over at least our portion of TX. This pattern also resembles the more classic upper ridge driven heat wave, as opposed to the plateau wind driven one from last week. As can be expected, this could mean the beginning of our effective summer as the westerly flow gets blocked. Similar to the previous heat wave, this upcoming hot period could be made more unpleasant by relatively light afternoon and evening winds with little help from isolated storm outflows or a sea breeze. On a positive note the ECM/GFS solutions do show a somewhat vulnerable upper ridge being chipped away by instability dropping south from the high plains and also a possible early monsoonal flow from Mexico, just outside the 7-day forecast window. && .AVIATION... (18Z TAFS) Issued at 1249 PM CDT Sat Jun 1 2024 A northward moving outflow boundary along with daytime heating should generate some isolated to scattered showers and storms for areas mainly along and east of I-35/I-37 this afternoon. For now, we will only mention VCSH at the I-35 sites as overall coverage should remain fairly low. MVFR clouds will return to all sites early Saturday morning as a potential complex of storms moves southward toward DRT. The latest hi-res and even a global model all show potential for storms at DRT early Sunday morning. For now, we will mention a PROB30 group between 06-11Z, but this may need to be adjusted pending radar trends. A few models also show some of this activity moving toward SAT and SSF early Sunday morning. For now, we will hold off and continue to monitor before adding to the forecast. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 76 94 78 95 / 10 10 0 10 Austin Bergstrom Intl Airport 75 93 77 94 / 10 10 0 10 New Braunfels Muni Airport 76 96 78 96 / 20 10 0 10 Burnet Muni Airport 74 90 75 92 / 10 10 10 10 Del Rio Intl Airport 80 100 82 100 / 30 10 0 10 Georgetown Muni Airport 73 91 76 92 / 10 20 0 10 Hondo Muni Airport 76 97 77 96 / 30 10 0 10 San Marcos Muni Airport 75 94 77 95 / 10 10 0 10 La Grange - Fayette Regional 77 92 77 93 / 10 20 0 0 San Antonio Intl Airport 78 96 79 95 / 30 10 0 10 Stinson Muni Airport 78 97 79 97 / 30 10 0 0 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Short-Term...Platt Long-Term...18 Aviation...Platt