Area Forecast Discussion
Issued by NWS Austin/San Antonio, TX
Issued by NWS Austin/San Antonio, TX
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643 FXUS64 KEWX 080724 AFDEWX Area Forecast Discussion National Weather Service Austin/San Antonio TX 224 AM CDT Sat Jun 8 2024 ...New SHORT TERM, LONG TERM... .SHORT TERM... (Today through Sunday) Issued at 216 AM CDT Sat Jun 8 2024 Early Saturday morning the upper level pattern across the U.S. shows an upper level ridge of high pressure centered of the NW Gulf...an upper low over Baja and broad NW flow from the Northern Rockies to the mid Atlantic. The upper ridge over the Gulf will dominate our weather in the short term allowing for deeper onshore flow and the return of higher moisture levels especially along the Rio Grande. Still waiting to see if in fact some low clouds will form down to our SE and move this general direction. Despite this possibility will keep with mostly sunny skies today because the moisture is fairly shallow, PW values still fairly low, and low level winds will be relatively strong...which should allow for good mixing. Out along the Rio Grande we could have some high clouds come across from Mountain storms. Models show dewpoints dropping into the mid to upper 60s again this afternoon. So even with the temps forecast to be in the mid to upper 90s, low 100s out west...we should stay below Heat Advisory criteria. We could see the S/SE winds gust over 20 kt in many spots by mid afternoon which should help to alleviate some of the heat issues. After several days of cloud free mornings...the surge in moisture will create a cloudy morning on Sunday. Temps will rebound quickly and still approach 100 in many areas under partly cloudy to mostly sunny skies. With the higher dewpoints expected we may get close to Heat Advisories especially along the Rio Grande Sunday afternoon. Max temps will once again be several degrees above normal. The good news is that the upper ridge over the N. Gulf starts to weaken to our east as the Baja low pressure area moves into the desert SW and merges into some NW flow. && .LONG TERM... (Sunday night through Friday) Issued at 216 AM CDT Sat Jun 8 2024 An upper level low currently over the southern half of the Baja peninsula will lift northward into the desert southwest through the weekend. Some weak upper level disturbances associated with this low as well as a 60-70kt subtropical jet will bring a low chance for some showers and thunderstorms Sunday night into Monday. As of now, it appears rain chances will remain low and mainly favored over the Hill Country and southern Edwards Plateau, where models show an outflow boundary/weak cold front may approach from the north. The GFS model has trended much weaker with this boundary and subsequently trended higher with the forecast highs on Monday. We will continue this trend as well and side with the warmer guidance on Monday into Tuesday. While we could see a weak easterly wind shift and some temporary lowering of dewpoints, we prefer to keep temperatures near or above normal behind the boundary. Southeasterly winds in the lower-levels are likely to return to all areas on Tuesday and we will quickly return to a hot and humid pattern across south central Texas. We will keep a low chance for some isolated late afternoon/early evening convection in the forecast across the coastal plains, with a dry forecast elsewhere. The remnants of the upper low mentioned above are expected to move across the Texas Panhandle into north Texas Tuesday into Wednesday. While some sort of convective complex will likely accompany this upper low, rain chances continue to remain favored well to our north. We will monitor for possible southward propagating outflow boundaries which may help initiate some convection across north and central Texas late Tuesday or Wednesday. Late in the forecast period, the mid and upper level subtropical ridge axis will strengthen to our west. Temperatures still appear to remain at or above normal with the low-level thermal ridge amplifying over the region. && .AVIATION... (06Z TAFS) Issued at 1241 AM CDT Sat Jun 8 2024 No major changes from the previous thinking but confidence is increasing that at least some low clouds will start to form to the SE as moisture advection increases over the next several hours. 00z model time sections of RH shows evidence of the low clouds forming and SREF probabilities of MVFR are rather high over the SAT area by dawn. Still only went with a Tempo group for MVFR at SAT/SSF as I have seen too many times the models bring back the surges too quick. Even if the ceilings do form, they should mix out fairly quickly in the AM hours and turn to VFR with some southerly winds gusting over 20 kt in the PM hours. Time sections of RH and MOS guidances point to widespread MVFR/IFR across the region on Sunday morning with SAT/SSF/AUS likely being affected. Have this mentioned as prevailing conditions by 09z Sunday at SAT/AUS. Will keep DRT VFR through the forecast. There is a low chance that the cigs on Sunday morning could work there way up the Rio Grande and get to Del Rio in the AM hours Sunday morning. Seasonal wind patterns will prevail...S/SE with PM gusts over 20 kt. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 96 75 96 75 / 0 0 0 0 Austin Bergstrom Intl Airport 96 74 95 75 / 0 0 0 0 New Braunfels Muni Airport 99 74 98 75 / 0 0 0 0 Burnet Muni Airport 94 72 93 73 / 0 0 0 10 Del Rio Intl Airport 103 80 103 81 / 0 0 10 10 Georgetown Muni Airport 95 73 93 73 / 0 0 0 0 Hondo Muni Airport 99 75 100 77 / 0 0 0 0 San Marcos Muni Airport 96 73 96 74 / 0 0 0 0 La Grange - Fayette Regional 94 74 93 75 / 0 0 0 0 San Antonio Intl Airport 98 76 98 77 / 0 0 0 0 Stinson Muni Airport 100 77 100 78 / 0 0 0 0 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Short-Term...09 Long-Term...Platt Aviation...09