FXUS64 KEWX 111517 AFDEWX Area Forecast Discussion National Weather Service Austin/San Antonio TX 917 AM CST Mon Dec 11 2023 ...New UPDATE... .UPDATE... Issued at 902 AM CST Mon Dec 11 2023 Have allowed the Freeze Warning to expire as of 9 AM given the latest surface observations. Any isolated sub-freezing temperatures lingering in low-lying areas should quickly improve over the next hour. Quigley && .UPDATE... Issued at 506 AM CST Mon Dec 11 2023 The expected light southerly flow never developed over the Rio Grande Plains, and so temperatures have dipped to near or below freezing in much of Kinney, Maverick, and Dimmit Counties. These counties have been added to the freeze warning as a result. Temperatures have also fallen to 32 degrees in San Antonio and 33 degrees at Austin Camp Mabry. && .SHORT TERM... (Today through Tuesday) Issued at 135 AM CST Mon Dec 11 2023 An extremely dry airmass is in place across Texas early this morning. The KCRP 00Z sounding recorded a 0.12" PWAT, which is a daily record low for the date/site. Meanwhile as a surface high slides to our east and a low develops in eastern NM, southerly winds have begun to increase over the Rio Grande Plains and southern Edwards Plateau. There, temperatures are unlikely to fall much more this morning. However, many locations in our central and eastern counties had winds go calm earlier than expected, allowing surface temperatures to plummet to at or below freezing in many low lying areas by midnight. Meanwhile, some higher elevation locations remained in the low 40s. Temperatures will continue to fluctuate some as winds ebb and flow through this morning. We do expect to quickly warm-up after sunrise, and it's possible the freeze warning can be cancelled slightly before it's scheduled 15Z expiration. Southerly winds will pick up over the rest of the region by mid-morning, and with nothing but sunshine today we'll see highs climb into the 60s. Winds become more easterly/southeasterly overnight into Tuesday which will increase our dew points into the upper 40s/lower 50s by Tuesday evening. In addition, as the next trough begins to approach from the west we'll see an increase in cloud cover from west to east late tonight through Tuesday. These factors should combine to keep overnight lows above freezing tonight areawide. Highs on Tuesday will reach the upper 60s and lower 70s in many areas, though western/northwestern portions of the area that see clouds build in early will only reach the upper 50s to lower 60s. && .LONG TERM... (Tuesday night through Sunday) Issued at 135 AM CST Mon Dec 11 2023 Models are in agreement in taking an upper level low over Arizona on Wednesday to over New Mexico on Thursday, then differ somewhat on the track and timing of the low over Texas on Friday into Saturday. A southwesterly flow aloft off the Pacific and a southeasterly lower level flow off the Gulf of Mexico will import an unseasonably moist airmass across most areas. Forcing strengthens generating chances of showers mainly over western parts of South Central Texas on Wednesday into Thursday. Chances will be much lower across eastern areas where a drier airmass lingers due to an easterly lower level flow there. As the upper level low moves over Texas, a cold front moves across the area on Friday. This will enhance forcing allowing for showers to spread to the east late Thursday into Friday. Some locally heavy rains up to 2 inches are possible and WPC has indicated a marginal risk of excessive rains out west for Thursday and most areas for Friday. If any flooding were to occur, it would be urban and small stream type. Minimal instability and weak mid level lapse rates indicate a potential for only isolated thunderstorms. Chances for showers linger across eastern areas through Saturday as the upper level low is in proximity while it moves toward the Gulf of Mexico. Due to the extensive cloudiness and showers on Wednesday through Saturday, below normal high temperatures and above normal low temperatures are expected with rather small daily temperature ranges. Next Sunday turns warmer with cloudiness decreasing as the upper level low moves out into the Gulf of Mexico. Still expect continued fine tuning of the forecast as we go through the next several days as there remain consistency and consensus issues among the models and ensembles. && .AVIATION... (12Z TAFS) Issued at 506 AM CST Mon Dec 11 2023 Clear skies will continue today, and VFR conditions remain forecast through the next 24-30 hours. Light drainage NW winds at KSAT continue this morning, with light ENE winds at KDRT, otherwise winds have largely been calm overnight. Look for 5-10 mph southerly flow to develop at the I-35 terminals today, then becoming light and variable again tonight. Some increase in high cloud cover will begin during the mid-morning hours on Tuesday. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 65 41 67 50 / 0 0 0 0 Austin Bergstrom Intl Airport 65 38 69 50 / 0 0 0 0 New Braunfels Muni Airport 65 41 70 52 / 0 0 0 10 Burnet Muni Airport 63 39 64 49 / 0 0 0 0 Del Rio Intl Airport 67 42 65 58 / 0 0 0 10 Georgetown Muni Airport 63 38 67 48 / 0 0 0 0 Hondo Muni Airport 65 40 68 54 / 0 0 0 10 San Marcos Muni Airport 64 39 69 50 / 0 0 0 10 La Grange - Fayette Regional 63 41 68 49 / 0 0 0 0 San Antonio Intl Airport 63 42 68 54 / 0 0 0 10 Stinson Muni Airport 66 43 70 55 / 0 0 0 10 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Short-Term...KCW Long-Term...04 Aviation...Quigley