764 FXUS64 KEWX 160512 AFDEWX Area Forecast Discussion National Weather Service Austin/San Antonio TX 1212 AM CDT Thu May 16 2024 ...New AVIATION... .SHORT TERM... (Tonight through Thursday night) Issued at 305 PM CDT Wed May 15 2024 High clouds continue streaming in from the west early this afternoon as temperatures remain in the 80s to near 90 degrees. Despite the high clouds, we should still manage to warm into the upper 80s to upper 90s by late afternoon. We will monitor the higher terrain west of the Rio Grande as the latest round of hi-res models continue to suggest isolated storms will develop and move eastward into the Rio Grande plains during the very late afternoon or evening hours. There is a Marginal Risk (level 1 of 5) for severe storms with large hail and damaging winds being the main severe weather concerns. With the loss of daytime heating, the chance for convection will decrease overnight. For tonight, plenty of southeasterly flow in the low-levels will bring an increase in moisture and result in widespread low cloud development. With some slightly stronger 850mb southerly flow over the region, will mention a low chance for light showers during the pre-dawn hours across portions of the Hill Country. For the remainder of the morning hours, a warm front will move northward through the region and help bring an increasing chance for showers and thunderstorms to most of south central Texas. For the afternoon, the latest guidance shows an active pattern will develop as a surface low and dryline moving across west central Texas meets the unstable air near and south of the warm front during peak heating. Thunderstorms will likely develop from west central Texas into the Texas Hill Country by late afternoon. Initial activity should be in the form of isolated supercells, with hi-res model trends showing clusters of storms across the Hill Country into portions of the I-35 corridor and coastal plains. SPC maintains a Slight to Marginal Risk (level 1 to 2 of 5) for severe storms across most of south central Texas, except for out west along the Rio Grande. Large to very large hail and damaging winds will be the main severe weather concerns. Areas along and north of a Kerrville to San Marcos to Schulenburg line will be under the higher risk area for severe storms. In addition, some locally heavy rainfall will be possible in a fairly narrow corridor from south of Waco to near of just north of Austin. A quick 1-2 inches with locally higher amounts seems reasonable across Burnet, Williamson and Lee counties. Rainfall amounts farther south will trail off rather quickly, with only up to around 1/4 inch near San Antonio. A decrease in convection should commence by late evening with the loss of daytime heating. && .LONG TERM... (Friday through Wednesday) Issued at 305 PM CDT Wed May 15 2024 The coastal plains east of I-35 has a slight chance of rain or a storm through Friday afternoon pending the speed of the weak frontal passage and with the last of the mid-level energy advancing across the state. Elsewhere, it stays rain free with a dry heat across our western zones while eastern areas remain more humid. The overnight lows into Saturday morning will trend the lowest of the long term ranging from the 60s into the low 70s. Rain chances become minimal and heat builds through the rest of the long term period as upper level ridging centered across Mexico to our southwest strengthens with time. This heat is not absent of humidity as surface high pressure to our east will allow for light to moderate south to southeasterly winds to prevail. Only exception from the humidity will be across our western zones where the heat trends drier pending the location of the dryline. However, high temperatures with the dry heat across those areas will easily rise above 100 degrees each afternoon. Speaking of 100 degrees, some locations near the I-35 corridor could potentially flirt with that mark sometime early to middle of next week. Otherwise, peak heat indices for locations with higher dew points are likely to top in the 103 to 108 degree range or higher. Unfortunately, this sort of heat is early again this year, and it's time to think about those heat safety precautions. && .AVIATION... (06Z TAFS) Issued at 1211 AM CDT Thu May 16 2024 VFR conditions will continue the next few hours before MVFR ceilings begin to move into South Central Texas as early as 08Z. Near 12Z, IFR conditions are likely at I-35 sites before lifting back to MVFR late morning into the early afternoon. Conditions will remain VFR at DRT through the rest of the period with SAT/SSF briefly seeing VFR conditions late this afternoon before low ceilings return to the eastern half of the area overnight into Friday morning. AUS may remain with MVFR conditions through tomorrow. Thunderstorms are expected to develop this afternoon along and north of a warm front. Storms may form or move over AUS this afternoon and evening and have continued the PROB30 group from 21Z Thursday through 01Z Friday. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 81 67 85 68 / 80 20 10 10 Austin Bergstrom Intl Airport 81 67 86 67 / 80 20 10 10 New Braunfels Muni Airport 85 69 88 68 / 60 20 10 10 Burnet Muni Airport 78 65 84 65 / 80 20 10 10 Del Rio Intl Airport 101 70 100 72 / 10 10 10 0 Georgetown Muni Airport 78 66 85 66 / 90 30 10 10 Hondo Muni Airport 88 67 93 69 / 30 10 10 0 San Marcos Muni Airport 83 67 87 67 / 70 20 10 10 La Grange - Fayette Regional 83 70 85 69 / 80 40 20 10 San Antonio Intl Airport 85 69 90 70 / 50 10 10 10 Stinson Muni Airport 87 71 90 71 / 50 10 20 0 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Short-Term...Platt Long-Term...Brady Aviation...27