Area Forecast Discussion
Issued by NWS Austin/San Antonio, TX
Issued by NWS Austin/San Antonio, TX
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083 FXUS64 KEWX 191740 AAA AFDEWX Area Forecast Discussion...UPDATED National Weather Service Austin/San Antonio TX 1240 PM CDT Wed Jun 19 2024 ...New AVIATION (18Z TAFS)... .SHORT TERM... (Today through Thursday) Issued at 257 AM CDT Wed Jun 19 2024 Key Messages: *Moderate to locally heavy rainfall will begin this morning and continue into early Thursday. *Confidence in the highest rainfall totals is seen across the far southern portions of the area where the Flood Watch remains. *Rain amounts have trended down overall. *Isolated tornado threat remains across our southeastern-most counties on Wednesday into Wednesday night. Discussion: All attention turns to Potential Tropical Cyclone One as it makes a turn west towards northeastern Mexico later today, reaching the coast late tonight or early Thursday. Early this morning, shower activity is noted over the Gulf Coast expected to reach the coastal plains near sunrise and I-35 corridor late morning. The Hill Country will see rain activity in the afternoon with it reaching our western reaches along the Rio Grande late afternoon or evening. Precipitable water values are on the rise this morning with values exceeding 2 inches over all of South Central Texas later today. Limited instability is forecast as rainfall moves across the area with only a few embedded thunderstorms expected. While the environment will support efficient rain rates, the heaviest rain totals have trended further south again with the latest model guidance. WPC has followed this trend with their Excessive Rainfall Outlook now only including a slight risk (level 2 of 4) for our southernmost tier of counties and the moderate risk (level 3 of 4) south of the CWA. Storm totals are now on the order of 0.25 to 1 inch north of I-10 with 1 to 3.5 inches in the southern half of the CWA. Locally heavier amounts are possible in any location with any bands of heavier precipitation. Due to the above, the Flood Watch has been trimmed of the northern tier of counties including Bexar/the San Antonio metro area. East to northeasterly wind will increase this morning with gusty wind remaining through tonight. Winds will gust anywhere from 20-35 mph through the evening and remain below Wind Advisory criteria. The low tornado risk remains mainly across the coastal plains later today and tonight with strong 0-1 km shear noted. Activity will begin to taper off after sunset in the east but continue over our western areas through Thursday morning. While some may see a lull in activity overnight, shower and thunderstorm chances increase again areawide Thursday afternoon with continued high PWATS still in place. Thunderstorm activity may be scattered with the potential for storms to produce heavy rain. WPC highlights the western portions of the area in a slight risk (level 2 of 4) for excessive rainfall for areas along the Rio Grande this day. Temperatures during this period of wet weather will be cooler with highs today topping out in the upper 70s and low 80s for a majority of the area. In the far west where activity moves into late today, some highs in the low 90s may still be seen. Slightly warmer for Thursday but mostly cloudy skies will limit highs to the mid 80s to low 90s across the area. && .LONG TERM... (Thursday night through Tuesday) Issued at 257 AM CDT Wed Jun 19 2024 The center of the Subtropical Ridge over the southeastern states on Friday shifts to over Texas this weekend to over the southwestern states/northern Mexico early next week. Another potential tropical system indicated in the southwestern Gulf of Mexico on Friday should move west into Mexico this weekend or early next week, though its impacts on South Central Texas are uncertain. NHC currently (19/06Z) has a 30 percent chance of tropical cyclone development. An unseasonably moist airmass with PWs generally 1.4 to 2.1 inches remains over South Central Texas through the period. While the Ridge will provide some subsidence to inhibit convection, heating and the potential tropical system should be able to overcome this for low chances of mainly daytime showers and thunderstorms, especially over our southern areas. Slightly below normal temperatures on Friday warm to slightly above normal this weekend into next week. With the increased soil moisture from the rain in the short-term, heat indices may reach advisory levels on Sunday into next week along and east of the I-35 corridor. && .AVIATION... (18Z TAFS) Issued at 1236 PM CDT Wed Jun 19 2024 To put it simply, the TAFS are a mess over the next 24-30 hours. The expectation is for rain to overspread the region from west to east over the next few hours, but with continued mention in the TAFS through the remainder of the period. MVFR to IFR Cigs are likely through the day today and should continue through midday Thursday before lifting to VFR by the early afternoon hours. Winds are expected to remain quite strong through this afternoon and evening, peaking after sunset between 20-25 kts, and gusting to 30-35 kts at times through early Thursday morning. Expect a mainly easterly to east-southeasterly component. A round of +RA is possible mainly between 22-02Z at SAT and SSF, with AUS seeing SHRA through the late evening hours. Have opted for PROB30s at AUS and SAT to account for scattered storms possible tomorrow afternoon. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 76 90 74 93 / 50 30 10 10 Austin Bergstrom Intl Airport 75 90 73 91 / 50 30 10 20 New Braunfels Muni Airport 75 90 74 91 / 70 50 10 30 Burnet Muni Airport 74 88 73 90 / 50 30 10 10 Del Rio Intl Airport 77 90 77 93 / 80 80 60 50 Georgetown Muni Airport 74 89 72 90 / 40 30 10 10 Hondo Muni Airport 73 87 74 89 / 70 60 20 30 San Marcos Muni Airport 73 88 72 90 / 60 40 10 20 La Grange - Fayette Regional 76 89 74 90 / 40 40 0 30 San Antonio Intl Airport 75 88 75 90 / 70 50 20 30 Stinson Muni Airport 76 89 76 91 / 60 50 10 30 && .EWX WATCHES/WARNINGS/ADVISORIES... Flood Watch through Thursday afternoon for Atascosa-De Witt-Dimmit- Frio-Gonzales-Karnes-Lavaca-Maverick-Wilson-Zavala. && $$ Short-Term...27 Long-Term...04 Aviation...MMM