Area Forecast Discussion
Issued by NWS Austin/San Antonio, TX
Issued by NWS Austin/San Antonio, TX
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059 FXUS64 KEWX 300703 AFDEWX Area Forecast Discussion National Weather Service Austin/San Antonio TX 203 AM CDT Thu May 30 2024 ...New SHORT TERM, LONG TERM... .SHORT TERM... (Today through Friday) Issued at 200 AM CDT Thu May 30 2024 A weak impulse has allowed for some isolated to scattered convection to move into Maverick County overnight and this activity should push southeast of the CWA shortly. Elsewhere, southeast winds are in place across the area with an abundance of high clouds associated with distant convection. Should begin to see some low-clouds develop later tonight. Temperatures are in the upper 70s to lower 80s and we will likely see low temperatures later tonight bottom out near 70 to the upper 70s with the cooler temperatures expected in the Hill Country. Most of the day should remain quiet but will carry some low PoPs in the eastern counties. There is a boundary near Houston that is slowly working west and this could provide some focus for shower and storm activity during the today period. High temperatures today will be similar to yesterday, topping out near 90 in the north to near 100 along the Rio Grande. The main focus for convection in the short-term will be during the tonight period. CAMs are fairly consistent that thunderstorms will develop in West Texas and the Panhandle along the dryline. However, there are some differences between the members of the short-term guidance about the overall evolution of any potential MCS once storms develop and potentially transition into an MCS as the cold pools become dominant. The ARW sends the system into the CWA early, while the FV3/NAM keep the system a bit later and weakening as it enters the CWA. The 00z HRRR has the MCS entering the Hill Country around 1-2am and does keep it ongoing through daybreak Friday. Will show PoPs in the 30-60 percent range tonight with the higher PoPs in the Hill Country where probabilities are high that some sort of effect from the system is likely. The latest Day 1 Outlook from SPC has most of the CWA at least in a Level 1 (marginal) risk of severe storms with a Level 2 (slight) risk in the northern Hill Country. This seems reasonable as this area is most likely to see some sort of impact from the potential MCS with the main question being the overall strength of it by the time is enters the CWA. The main risk with any storms will be damaging winds but hail and perhaps an isolated tornado cannot be ruled out. Lows tonight will likely be near 70 in the Hill Country ranging up to the upper 70s in the west and southern counties. Lows will likely be influenced by convection with potential rain cooling to the surface. The forecast Friday will definitely be impacted by what occurs tonight. Models that show decent widespread convection tonight show little convection during the day on Friday as the atmosphere will likely be pretty well worked over. Will undercut the elevated NBM PoPs for now as we lean more to that solution. Highs Friday will be in the upper 80s to upper 90s across the region. && .LONG TERM... (Friday night through Wednesday) Issued at 200 AM CDT Thu May 30 2024 The unsettled weather pattern continues at least through the first half of the weekend. The timing and location of each round of rain and storms will remain difficult to pinpoint and ultimately depends on how well the atmosphere recovers from the previous rounds of storms and/or outflow. The same general triggers for storms remain in place across the state. This includes shortwave disturbances embedded within the west-northwesterly mid-level flow above the upper level ridge centered across Mexico, the dryline towards the west, a lingering surface front to the north, and any remaining outflow boundaries from previous rounds of convection. Storms will be capable of becoming strong to severe with any round from the result of moderate to strong instability and sufficient deep layer shear profiles over the area. Storms will be capable of heavier rainfall rates as well and could pose a risk of flooding pending previous rainfall, speed of storms, and antecedent soil moisture. Temperatures will continue to run a little above climatological average through the weekend. Medium range guidance, including the ensemble means, continue to indicate some decline of the area rain chances and an increase in the heat next week as the upper level ridge centered over Mexico builds northward and transitions toward an Omega Block pattern. Given that the ridge becomes more centered to our west, the flow aloft turns more northerly across South-Central Texas. While the rain chances generally do look to lessen, this is not expected to completely eliminate them out of the forecast as that northerly steering flow could help promote the approach of outflow and/or an upper level disturbance or two advancing out of the central and southern plains along the eastern periphery of the ridge. Some guidance indicates this potential toward the middle of next week. Afternoon highs climb back to the mid 90s for many near the I-35 corridor and up into the 100 to 105 degree range along the Rio Grande. With the dew points forecast to remain elevated, the heat indices could approach and/or reach Heat Advisory levels across portions of the region at times next week. Overnight lows remain elevated in the 70s to near 80 degrees as well. && .AVIATION... (06Z TAFS) Issued at 1211 AM CDT Thu May 30 2024 High clouds from convective debris stream across the area, but we should see some MVFR ceilings develop before too long at the I35 sites and then later overnight at DRT. Can`t rule out some brief IFR but overall chances were too low to mention. VFR will then return by the late morning hours. The next chance of rain will arrive to AUS after 6z tomorrow night and perhaps 9-12z for SAT. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 73 89 74 90 / 50 40 30 20 Austin Bergstrom Intl Airport 72 88 74 90 / 50 40 30 20 New Braunfels Muni Airport 74 92 74 92 / 50 30 30 20 Burnet Muni Airport 71 84 72 87 / 60 40 30 20 Del Rio Intl Airport 79 98 78 101 / 20 10 20 10 Georgetown Muni Airport 70 87 72 87 / 50 50 30 20 Hondo Muni Airport 75 94 75 94 / 40 20 30 10 San Marcos Muni Airport 72 91 74 90 / 50 40 30 20 La Grange - Fayette Regional 74 88 75 89 / 40 40 30 30 San Antonio Intl Airport 74 92 76 92 / 40 30 30 10 Stinson Muni Airport 76 94 76 94 / 40 30 30 10 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Short-Term...29 Long-Term...Brady Aviation...29