858 FXUS64 KEWX 150844 AFDEWX Area Forecast Discussion National Weather Service Austin/San Antonio TX 244 AM CST Mon Nov 15 2021 .SHORT TERM (Today through Tuesday)... The Night time Microphysics satellite imagery shows no low clouds yet developing across the area. However, the GOES Fog and Low Stratus (FLS) imagery is showing signs for low clouds to develop soon across the southwest part of south central Texas. Current surface observations across the southwest range from temperatures in the mid to upper 50s and even lower 60s with dewpoints in the upper 40s to lower 50s. Now the interesting part of the short term forecast (next 6 to 8 hours), temperatures across the coastal plains and along and east of the I-35 corridor are coming around the mid to upper 50s and lower 60s with dewpoints around one to two degrees away from the current temperatures with a hand full of reports coming in with readings at 100 percent relative humidity (actual temps = dewpoint temperatures). So, why clouds or fog are not forming yet? Well, out to the southwest winds are light and even calm versus winds across the coastal plains and along I-35 are coming in around 4 to 7 mph with gusts of 10 to 20 mph. So guess what, moisture is battling with the winds at this time. However, the wind is projected to calm down a bit within the next few hours, closer to sunrise, and then we will see low clouds and fog forming and spreading quickly across most of the southern part of south central Texas including the I-35 corridor. It won't last long as winds pick up late morning and clouds and fog lifts. There could be areas experiencing areas of dense fog around 7 or 8 am, and will be monitoring closely the situation in case of needing a short fused Fog Advisory. Otherwise, dry and warm with highs ranging from the mid to upper 70s into the mid 80s. A similar situation is expected for tonight into Tuesday morning with low clouds and fog developing overnight. Patchy to areas of fog are possible across the coastal plains and I-35 corridor. Once clouds and fog mixes out, a sunny day is in store with highs in the mid to upper 70s and into the mid 80s over parts of the southwest counties of the local area. && .LONG TERM (Tuesday Night through Sunday)... Zonal flow aloft will be in place Tuesday night to start the long term, but this will begin to transition into the base of a broad upper trough as a large upper low moves across Southern Canada and the upper trough digs into the Central Plains. The trough will help drive a cold front through South Central Texas late Wednesday night and into Thursday morning. Dewpoints in the 60s will combine with lift from both the front and a disturbance moving through the base of the large trough to produce a slight chance of precipitation during the early morning hours Thursday across areas along and east of I-35. While the GFS shows limited instability ahead of the front, the NAM (with the FROPA now within the model window) is a bit more bullish with nearly 1000 j/kg of CAPE. This is certainly nothing to write home about, but at least enough instability to warrant the mention of an isolated thunderstorm along with the showers as the front moves through. Temperatures ahead of the front on Wednesday will warm into the lower 80s area wide as decent southerly flow with breezy conditions continue. Behind the front for Thursday and Friday cooler and much drier air returns. Afternoon highs will be in the mid to upper 60s both days, back below seasonal normals. The cooler air will be short lived as the surface high quickly moves eastward bringing back southerly flow by Saturday. Models remain in disagreement about the potential for a front next weekend with the ECMWF bringing the front through mid-day Sunday, the GFS late Sunday into Monday, and the Canadian mid-day Monday. For now will continue with the NBM forecast of just slight chance PoPs for Sunday until models come into better agreement with the frontal timing. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 80 60 79 62 81 / 0 0 0 0 0 Austin Bergstrom Intl Airport 81 58 80 60 82 / 0 0 0 0 0 New Braunfels Muni Airport 81 58 81 60 83 / 0 0 0 0 0 Burnet Muni Airport 79 59 78 60 79 / 0 0 0 0 0 Del Rio Intl Airport 84 58 84 57 81 / 0 0 0 0 0 Georgetown Muni Airport 80 59 79 61 81 / 0 0 0 0 0 Hondo Muni Airport 83 56 82 56 83 / 0 0 0 0 0 San Marcos Muni Airport 81 58 81 60 82 / 0 0 0 0 0 La Grange - Fayette Regional 82 61 82 63 83 / 0 0 0 0 0 San Antonio Intl Airport 80 59 79 60 81 / 0 0 0 0 0 Stinson Muni Airport 83 61 83 62 85 / 0 0 0 0 0 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Short-Term/Aviation...17 Long-Term...Treadway