Area Forecast Discussion
Issued by NWS Austin/San Antonio, TX
Issued by NWS Austin/San Antonio, TX
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631 FXUS64 KEWX 200520 AFDEWX Area Forecast Discussion National Weather Service Austin/San Antonio TX 1220 AM CDT Thu Jun 20 2024 ...New AVIATION... .UPDATE... Issued at 1026 PM CDT Wed Jun 19 2024 The tornado Watch over Atascosa, Dewitt, and Karnes counties has been cancelled as the greatest threat for brief isolated tornadoes will remain concentrated across South to Deep South Texas through the overnight hours. Adjusted grids as well, including PoPs, to match latest radar and observational trends. There was some decent rainfall that had fallen across portions of our northeastern most counties this evening that had been forecast to see some lower amounts from this event. Some locations received 1 to 3 inches of rain with a few localized higher amounts. However, this band has weakened and producing less efficient rainfall rates. Otherwise, rainfall has been greatest east of I-35 and south of I-10 as forecast. && .SHORT TERM... (Tonight through Thursday night) Issued at 224 PM CDT Wed Jun 19 2024 Key Messages: *Moderate to locally heavy rainfall will 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 into this evening. Discussion: Rain bands from what is now the first named storm of the season, Alberto, are moving in over South Central Texas with some embedded thunderstorms. So far, rainfall rates have been tame, but as heavier showers move into the region, especially south of I-10, any embedded thunderstorms could contain rainfall rates of 1-2"/hour. There is still a low end threat for flooding and flash flooding, and the Flood Watch remains in effect for our southern tier of counties through midday Thursday. Overall, rainfall totals are expected to remain between 1-3 inches over the southern CWA, with between 0.5-2" for the remainder of the area. The 12Z sounding out of CRP showed PWATs in excess of 2.5" along with a nearly saturated profile all the way up to 100mb. Long, skinny profiles, along with modest CAPE and high moisture environments can produce significant tropical rainfall. Despite lowered amounts, this is still a beneficial event, as it will act to keep temperatures down during what is usually one of the hottest and most humid months of the year and it should help limit short term drought impacts as we add some moisture to area soils without widespread severe weather. Speaking of severe weather, there is a Marginal Risk (Level 1 of 5) for tornadoes over the Coastal Plains, but the primary concern continues to be locally heavy rainfall and the low end chance for flooding. The heavier rain threat should end from east to west by sunrise Thursday, but there is still a threat for widely scattered showers and storms to develop Thursday afternoon. The primary threat would be locally heavy rainfall, but widespread flooding and flash flooding are not expected at this time beyond 18Z Thursday. Temperatures will remain some 5-15 degrees below normal for late June as well, so the first official day of Summer will certainly not feel like it across South Central Texas. && .LONG TERM... (Friday through Wednesday) Issued at 224 PM CDT Wed Jun 19 2024 As the remnants of Alberto dissipate over Mexico there will still be a deep, moist airmass over South Central Texas. Chances for showers and thunderstorms will continue Friday with the best chances along and south of I-10/Hwy 90. The low level flow over the weekend and early next week will be from the southeast. This will keep a warm, moist airmass in place. A weak upper ridge will allow for isolated convection driven by daytime heating each day Saturday through Wednesday over the Coastal Plains. Some days the storms will spread toward the west and north. Chances will mostly be slight and most places will remain dry through the period. Temperatures will slowly warm through the long term to back above normal by the middle of next week. && .AVIATION... (06Z TAFS) Issued at 1220 AM CDT Thu Jun 20 2024 Rain is moving west across South Central Texas with some heavier bands forming behind the main cluster of showers. Prevailing rain showers should end at I-35 sites around 08Z with only some VCSH expected to linger near SAT/SSF through 10Z. DRT will likely see -RA through this morning. The lull in activity is short lived as scattered showers and thunderstorms are expected to redevelop across the area this afternoon. Ceilings will generally be VFR/MVFR, with IFR ceilings possible for the Hill Country, Rio Grande Plains, and southern I-35 corridor near 10Z. Gradual improvement will be seen in the morning although MVFR conditions may linger into the afternoon for many locations. Gusty northeasterly wind will persist today with gusts from 20-25 knots shifting from the east after 00Z Friday. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 90 75 93 74 / 30 10 10 0 Austin Bergstrom Intl Airport 90 74 91 72 / 30 10 20 0 New Braunfels Muni Airport 88 74 91 72 / 50 10 30 0 Burnet Muni Airport 88 74 90 72 / 30 10 10 0 Del Rio Intl Airport 90 77 93 77 / 60 60 50 20 Georgetown Muni Airport 89 73 90 72 / 30 10 10 0 Hondo Muni Airport 88 74 89 73 / 50 20 30 10 San Marcos Muni Airport 89 72 90 71 / 40 10 20 0 La Grange - Fayette Regional 90 74 90 73 / 30 0 30 0 San Antonio Intl Airport 89 75 90 74 / 50 10 30 10 Stinson Muni Airport 89 76 91 75 / 50 10 30 0 && .EWX WATCHES/WARNINGS/ADVISORIES... Flood Watch through this afternoon for Atascosa-De Witt-Dimmit-Frio- Gonzales-Karnes-Lavaca-Maverick-Wilson-Zavala. && $$ Short-Term...Brady Long-Term...05 Aviation...27