Area Forecast Discussion
Issued by NWS Austin/San Antonio, TX
Issued by NWS Austin/San Antonio, TX
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169 FXUS64 KEWX 092256 AFDEWX Area Forecast Discussion National Weather Service Austin/San Antonio TX 556 PM CDT Thu May 9 2024 ...New MESOSCALE UPDATE... .MESOSCALE UPDATE FOR SEVERE THUNDERSTORM WATCH 224... Issued at 548 PM CDT Thu May 9 2024 Severe thunderstorms have developed along a cold front and dryline in Central TX and are moving toward the southeast. We expect additional storms to develop this evening as the boundaries move toward our CWA. We have issued a Severe Thunderstorm Watch for most of the Hill Country and northern I-35 Corridor until midnight tonight. Thunderstorms will be capable of producing hail up to three inches in diameter, wind gusts up to 80 mph, and a tornado or two. && .SHORT TERM... (Tonight through Friday night) Issued at 340 PM CDT Thu May 9 2024 Early this afternoon a surface cold front stretched from north Texas into a triple point in west central Texas with the dryline extending south from there. Very humid and warm conditions exists south of the cold front and east of the dryline, along with very unstable conditions above the cap. The cap is still present on ACARS soundings out of AUS, but has shown initial signs of a weakening trend. The strong surface heating should continue this trend into the late afternoon across the Hill Country and Austin metro area. CAMs have been indicating upstream convection along the aforementioned surface features to enter Llano and Burnet counties after 5 PM and into the Austin metro area after 7 PM. A few WoFS members are initiating convection ahead of the dryline as far south as Medina and Kendall after 5 PM. MLCAPE values are forecast to be an impressive 3500-4500 J/kg south of the cold front and east of the dryline, and with sufficient effective bulk shear values isolated storms developing into or over the Hill Country and into the I-35 corridor near Austin will be very capable of producing very large hail and damaging straight-line winds. An isolated tornado can`t be ruled out. A Level 2-3 out of 5 risk for severe storms is still in place for this area. It`s less certain how far south the storms can make it into the mid and late evening as convective inhibition begins to build into the Coastal Plains and San Antonio metro area, but we will watch these areas closely. The storms are eventually forecast to weaken and dissipate late evening east of I-35 and north of I-10. The cold front is forecast slip through most of the central and eastern areas tonight. Drier and "cooler" air will be in place for Friday. The front should also help to sweep a lot of the haze out of the area, which has partially been caused by background residual smoke in the air originating from seasonal burnings in Mexico and Central America. The cold front is forecast to hang up along the Rio Grande Friday morning. Models have been consistent with developing convection across this region midday Friday, with downstream development and propagation back into the western Hill Country and possibly San Antonio metro area in the afternoon. Isolated strong to severe storms could be possible Friday afternoon into the early evening. SPC has placed portions of the Rio Grande, southern Edwards Plateau, western Hill Country, and San Antonio metro area in a Level 1 out of 5 risk for severe storms Friday, with large hail the primary risk. Finally, temperatures this afternoon across western areas along the Rio Grande and south of U.S. 90 will top out around 100-105 degrees, with mid 90s into the western Hill Country, San Antonio metro, and inland Coastal Plains. East of the dryline, these temperatures combined with the humidity may cause heat illness for those that are not acclimated to the early season heat or are not taking proper heat precautions. We have issued a Special Weather Statement for this. High temperatures Friday are forecast to range from the low to mid 80s north of I-10 to upper 80s to low 90s south. && .LONG TERM... (Saturday through Thursday) Issued at 340 PM CDT Thu May 9 2024 A period of active weather will likely continue across portions of the long-term portion of the forecast. However, wide spread chances for significant severe weather will not be as high this weekend as in the short-term. A subtle disturbance will move into the area this weekend providing some lift for a 20-40 percent chance of showers and isolated storms mainly out west Saturday. This activity will transition into much of the remainder of the forecast area for Sunday with increasing PoPs. Overall, instability amounts will be meager but given the convective season, can`t completely rule out a strong storm at times during the weekend. Rain amounts for the weekend will likely average a half an inch or less for most locations but some isolated higher amounts will also be possible. For early next week, a weak boundary may bring additional rain chances to portions of the CWA on Monday. If this were to verify some severe weather may be possible as instability amounts are expected to increase. After probable dry weather on Tuesday, another disturbance could bring additional chances of thunderstorms Wednesday evening. Highs this weekend will mostly be in the 70s and 80s but will return into the 80s and 90s next week. && .AVIATION... (18Z TAFS) Issued at 1242 PM CDT Thu May 9 2024 Most locations are VFR midday, with the exception of some BKN MVFR ceilings still east of I-35 and I-37, which will scatter our shortly. The VFR conditions will continue through the afternoon and evening hours, away from any convection. In addition, haze will continue across portions of south central Texas south of a cold front and east of the dryline, at times reducing visibility to 6SM. TSRAs developing across north and central Texas through the afternoon hours near where the dryline intersects a southward moving cold front. A few of these TSRAs could impact areas near and north of a AQO-AUS-3T5 line through the evenings hours. Environmental conditions support some storms to become severe, producing very large hail and wind gusts in excess of 50KT. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 70 85 65 82 / 40 10 10 10 Austin Bergstrom Intl Airport 70 83 65 81 / 40 10 10 10 New Braunfels Muni Airport 71 86 67 84 / 20 10 10 20 Burnet Muni Airport 66 81 63 78 / 40 10 10 20 Del Rio Intl Airport 76 89 72 86 / 10 60 40 40 Georgetown Muni Airport 67 81 63 79 / 50 10 10 20 Hondo Muni Airport 72 87 68 83 / 0 20 10 20 San Marcos Muni Airport 70 84 65 82 / 20 10 10 10 La Grange - Fayette Regional 72 86 67 82 / 30 10 10 10 San Antonio Intl Airport 72 86 68 82 / 10 20 10 20 Stinson Muni Airport 74 87 69 84 / 10 20 10 20 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Mesoscale...05 Short-Term...76 Long-Term...29 Aviation...76