Area Forecast Discussion
Issued by NWS Austin/San Antonio, TX
Issued by NWS Austin/San Antonio, TX
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835 FXUS64 KEWX 050208 AFDEWX Area Forecast Discussion National Weather Service Austin/San Antonio TX 808 PM CST Mon Nov 4 2024 ...New UPDATE... .UPDATE... Issued at 801 PM CST Mon Nov 4 2024 Updated the forecast for slightly more SW coverage of the squall line. With the training potential currently being observed and forecast by the HRRR, we could see some locally heavy stripes of 4 inch rains over the eastern Hill Country, enough to warrant a brief FFW threat. Our severe threat appears to be waning to a small hail and gusty wind as the squall line continues to congeal. && .SHORT TERM... (Tonight through Tuesday night) Issued at 1244 PM CST Mon Nov 4 2024 ...A Line of Isolated to Scattered Strong to Severe Thunderstorms Expected this Evening for Locations near and East of the I-35 Corridor... A breezy, warm, and moist southerly flow has continued into the early afternoon across a majority of the region but winds decrease going towards the west where a dryline is now entering portions of the Southern Edwards Plateau. Skies remain mostly cloudy east of I-35 with a few remaining embedded showers, but these will become less common through early to mid-afternoon. Out west, in the Hill Country, clouds are breaking ahead of the dryline and this has led to some vertical growth recently for showers across that area. This activity moving into Burnet and western Travis/Williamson counties will be where a pre-frontal storm or two could establish before activity quickly moves north into the FWD CWA. The main thunderstorm risk arrives this evening as a cold front overtakes the eastward advancing dryline. The short term guidance has become more consistent on showing a broken line of thunderstorms unzippering in the vicinity or just west of the I-35 Corridor north of San Marcos this evening. With moderate instability (MLCAPE into the 1500 to 2500 J/kg range) along with increasing bulk shear will allow for storms to trend strong to isolated severe levels. Primary hazards would be strong damaging winds followed by large hail but adequate low-level shear and directional turning of the winds exist for a low end tornado threat as well. Activity will progress eastward later tonight into the coastal plains. The SPC has expanded the level 2 of 5 risk of severe weather on the latest Day 1 Convective outlook more southeastward to include San Marcos, Gonzalez, and La Grange. The level 1 of 5 risk otherwise remains very similar to the previous outlook. In addition to the severe weather risk, intense rainfall rates and initial slow storm movement could lead to storms quickly producing 2+ inches in a short period of time and the threat of isolated flash flooding across the region. Thunderstorm intensity likely wanes beyond midnight to 2 am across our central and eastern zones but short term guidance still continues to suggest some elevated post-frontal showers filling in across the region. This activity should gradually shift eastward with time as well but it may take until the mid to late Tuesday morning timeframe to shift out of our CWA to the east. Skies will otherwise clear out from northwest to southeast into and during Tuesday afternoon. The post-frontal north to northwesterly flow ushers in a drier and slightly cooler airmass across the region through Tuesday and into Tuesday night. Daytime highs on Tuesday will generally run within the 70s while the overnight lows for late Tuesday night into early Wednesday morning drop into the low to mid 40s within the coolest valleys to the upper 40s and low 50s elsewhere. && .LONG TERM... (Wednesday through Monday) Issued at 1244 PM CST Mon Nov 4 2024 Our more active weather pattern is expected to continue through the long term period of the forecast. On Wednesday, southwest flow at the 500mb level will continue ahead of the next approaching upper level low diving southeast out of the Rockies for late week. This will be our next rainmaker. Surface flow out of the south will increase once again ahead of this upper-level disturbance, and upper level support should be sufficient to support a low to medium chance for showers and thunderstorms Thursday and again on Friday. Medium range guidance keeps us in southwest flow until Saturday when the upper low mentioned above finally moves northeast and lifts out of north Texas. That should set the stage for a rather nice weekend with highs in the 70s and mornings in the 50s. && .AVIATION... (00Z TAFS) Issued at 548 PM CST Mon Nov 4 2024 Radar trends look to be in line with the latest HRRR runs in taking through a near continuous squall line through the metro cities between 03Z and 07Z. AUS will likely see the first wind shift from the gust front, as early as 03Z. At SAT, feeder cells east of the developing line could potentially create some shifty winds before the main line draws near by 04Z. SSF should see the latest TEMPO group to end around 07Z. Some hail and wind gusts to near 40 knots are possible with the stronger activity more probable over Central TX around AUS. Meanwhile, the frontal shift has already reached DRT, and only a few low impact showers are forecast for late tonight. Similarly the conditions should improve quickly along I-35 after midnight and a few residual showers could occur through 12Z. Post frontal winds are shown in all the MOS guidances to be higher in the several hours behind the front, with not much of a mixing boost for gusts expected after daybreak. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 59 73 52 79 / 80 20 0 0 Austin Bergstrom Intl Airport 60 74 47 78 / 80 20 0 0 New Braunfels Muni Airport 61 76 51 81 / 80 20 0 0 Burnet Muni Airport 57 71 49 77 / 60 10 0 0 Del Rio Intl Airport 58 75 50 83 / 20 10 0 0 Georgetown Muni Airport 58 71 48 76 / 80 20 0 0 Hondo Muni Airport 60 78 48 81 / 50 20 0 0 San Marcos Muni Airport 59 74 48 79 / 80 20 0 0 La Grange - Fayette Regional 62 72 50 78 / 90 30 0 0 San Antonio Intl Airport 62 77 53 79 / 80 20 0 0 Stinson Muni Airport 63 77 52 81 / 80 20 0 0 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Short-Term...18 Long-Term...MMM Aviation...18