Area Forecast Discussion
Issued by NWS Austin/San Antonio, TX
Issued by NWS Austin/San Antonio, TX
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251 FXUS64 KEWX 281122 AFDEWX Area Forecast Discussion National Weather Service Austin/San Antonio TX 622 AM CDT Tue May 28 2024 ...New UPDATE, AVIATION... .UPDATE... Issued at 602 AM CDT Tue May 28 2024 Pushed up the timing of the initial PoPs (20-30%) a little earlier into this afternoon as it`s possible that outflow from ongoing severe storms in the FWD CWA could push into the region and help trigger activity. Lowered highs a tad across northeastern locations as well given this possible outflow. With this said, the main round for storms and severe weather remains on target for this evening into tonight as highlighted within the short term discussion below. && .SHORT TERM... (Today through Wednesday) Issued at 305 AM CDT Tue May 28 2024 * Level 2 to 3 out of 5 risk for severe storms from this evening through tonight across all of South-Central Texas. Greatest concerns are damaging straight line winds and large hail. * Heavy rainfall expected with a level 2 out of 4 risk for flash flooding, especially for our northern and northeastern most counties. * Dangerous heat lingers for one more afternoon with peak heat indices as high as 110 degrees across our southern most areas. Today starts off very warm and humid once again with returning clouds and hazy skies. Couldn`t rule out some patchy fog early as well. Additionally, it should start off quiet on the radar with rain/storm chances not expected to arrive until this evening and into tonight. With majority of the latest CAM guidance indicating the slower arrival of any storms and outflow towards the evening hours, a concern for dangerous heat will linger today despite greater cloud coverage compared to recent afternoons. Highs will likely reach the mid to upper 90s for locations along and east of the I-35 corridor and near/above 100 degrees in the Rio Grande Plains. Heat indices are likely to peak in the 104 to 112 degree range and this will prompt a Heat Advisory across our southern most rows of counties. A shortwave embedded within the west-northwesterly mid-level flow along with the placement of a stationary front over Central Texas will help initiate several regions of convection this afternoon across the Texas panhandle, portions of North and West Texas and into the higher terrain of Mexico. Convection will likely congeal into one large organized singular MCS moving south-southeastward and/or a couple of separate individual clusters. As activity is advancing towards and across our region from this evening through tonight, it likely will be mainly cold pool driven. This favors damaging straight line winds as the greatest concern regarding severe weather where gusts of 65 to 75 mph or greater may be possible. Large to very large hail (1-2+" in diameter) will be a secondary concern with the largest hail favoring from the Hill Country and points north. An isolated tornado or two will be possible as well. This MCS and/or complexes will also result in heavy rainfall and some concern for flooding will exist across the region. Latest 24h HREF ensemble probability matched mean (PPM) guidance shows the potential for 1 to 3 inches of heavy rain with locally higher amounts where the MCS and/or complexes transverse across. At the time of this forecast discussion, the most favored area stretches from our northern/northeastern counties and into the SJT/FWD/HGX CWAs. Rainfall will be more sparse outside of these convective complexes. Wednesday should escape the dangerous heat we have seen over the past week with cooler outflow driven air in wake of the convective complexes. High temperatures range from the mid 80s across our northern/eastern counties into the mid 90s along the Rio Grande. Rain chances will be low to start off the day but gradually return towards late in the day and into Wednesday evening. While a few strong to severe storms are possible, it`s a less of a concern compared to this evening/tonight`s threat. && .LONG TERM... (Wednesday night through Monday) Issued at 305 AM CDT Tue May 28 2024 A possible active period continues for much of the long-term portion of the forecast. The forecast for Wednesday night will be somewhat dependent on what occurs today and tomorrow afternoon, but if convection does move through the area during the short-term a boundary will likely be setup over the area by Wednesday night. If this does occur we will likely see some scattered convection ongoing at the beginning of the long-term period Wednesday evening across the Edwards Plateau. This activity would then move southeast before likely dissipating by midnight. Instability amounts would support the possibility of a strong to severe storm. The new Day 2 outlook from SPC has most of the area in a level 1 out of 5 (marginal) risk for severe storms to cover this threat. Isolated to scattered convection will continue to be possible mainly during the afternoon periods. It will remain difficult to truly pinpoint location and timing as much of what occurs each day will be highly dependent on what occurs during the previous day or two as boundary interactions remain a key role in thunderstorm development. Have undercut NBM PoPs slightly through the period as they seem a bit too high at times. High temperatures through Friday will range from near 90 in the northern CWA to near 100 degrees in the Rio Grande Plains with lows in the 70s. Upper heights will rise a bit for the weekend which will begin to lower the overall rain chances by Sunday or Monday. This will also allow temperatures to slightly increase as well with highs Monday likely back in the middle 90s to near 104 degrees near the Rio Grande. && .AVIATION... (12Z TAFS) Issued at 602 AM CDT Tue May 28 2024 VFR to MVFR flight conditions prevail during this morning at the terminals. Slight visibility reductions are possible as result of either haze or patchy fog. Thunderstorm potential returns from late this afternoon into tonight as convection likely arrives in the form of a large complex or individual clusters moving from out of north and west Texas. The confidence still remains rather low regarding the exact timing, placement, and intensity of activity as it advances through the area. However, there is potential for storms to become severe with large hail, and strong damaging winds. Expect some reductions to VSBY, perhaps CIGs in SHRA/TSRA. The winds outside from convective influences become breezy today from out of the east- southeast. The ceilings overnight tonight into Wednesday morning as the convective storms decrease across the area will likely prevail and hold within the IFR to MVFR range. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 94 72 88 73 / 30 70 40 30 Austin Bergstrom Intl Airport 94 72 88 72 / 30 60 40 30 New Braunfels Muni Airport 98 74 91 73 / 20 50 30 20 Burnet Muni Airport 91 69 85 71 / 30 70 40 30 Del Rio Intl Airport 100 76 98 78 / 20 40 20 20 Georgetown Muni Airport 91 69 86 71 / 30 70 40 30 Hondo Muni Airport 98 72 93 73 / 20 60 20 20 San Marcos Muni Airport 96 72 90 72 / 30 50 30 20 La Grange - Fayette Regional 95 74 88 73 / 30 50 40 20 San Antonio Intl Airport 97 74 91 75 / 20 60 30 20 Stinson Muni Airport 98 75 93 76 / 20 40 20 20 && .EWX WATCHES/WARNINGS/ADVISORIES... Heat Advisory from noon today to 7 PM CDT this evening for Atascosa- De Witt-Dimmit-Frio-Gonzales-Karnes-Lavaca-Maverick-Wilson-Zavala. && $$ Short-Term...Brady Long-Term...29 Aviation...Brady