354 FXUS64 KEWX 221154 AFDEWX Area Forecast Discussion National Weather Service Austin/San Antonio TX 554 AM CST Sun Dec 22 2024 ...New AVIATION... .SHORT TERM... (Today through Monday) Issued at 141 AM CST Sun Dec 22 2024 Key Messages... - Warmer weather Sunday and Monday with increasing humidity. - A slight chance of light rain or sprinkles near the escarpment tonight/Monday morning. Low clouds are returning over the area today in a piecemeal fashion, with southerly H850 winds giving the 5000 foot layer saturation first and the mostly east surface winds being slower to saturate the lowest levels. A few pockets of lower ceilings below 2000 feet are forming along the western escarpment from Uvalde to north San Antonio, but with dewpoints still in the 30s and 40s to suggest the moistening arriving at the boundary layer level. Meanwhile areas east of I-35 may have to wait until late this morning for lower cigs and possibly not until early this evening. The coverage of ceilings above this level should be more continuous and even the skies over our far eastern counties should encounter a few periods where skies are mostly cloudy. The cloud impacts should hold max temps below 70 degrees along and NW of Del Rio to San Antonio to Taylor. Even the areas that should see more sunshine will probably be capped in the 70-75 degree range. Light showers have been a signal by the NAM and some of the high res models for tonight into early Monday mainly over the western escarpment. Measurable rains can not be ruled out, but the highest amounts should be only around 5 hundredths of an inch. Some patchy fog may also form in the areas where these low rain chances are expected. South winds in the moist layer are expected to ramp up tonight which should combine with the cloudiness to hold min temperatures up to well above December normals. The high mins and southerly winds will also contribute to a daytime warming trend to bring most areas into the 70s despite the continued abundance of clouds. && .LONG TERM... (Monday night through Saturday) Issued at 141 AM CST Sun Dec 22 2024 Key Messages... -Way above normal temperatures throughout the period -Multiple albeit weak systems will impact mostly eastern areas of our CWA Temperatures starting Monday night will be running way above normal due to the return of southerly winds pumping in moisture and clouds due to onshore flow. Our overnight lows will range anywhere from the upper 50s to lower 60s. While highs will range from lower to middle 70s each day which is 10-15 degrees above climatological averages for this time of year(lower 60s). With the warm temperatures also comes the increase in humidity values so it could feel a big muggy the next few days before drier air moves in on Saturday. Speaking of moisture, we seem to be turning the corner when it comes to systems impacting mainly our eastern areas with 3 systems waiting in the wings for us. The first system as has been previously advertised in prior discussions looks to impact our area mainly on Christmas Eve as a cold front pushes through our area. Global models continue to back off on moisture overspreading the area. Additionally when looking at the chances for strong thunderstorms with this system, instability values for MUCAPE look to max out at around 700 j/kg when storms initiate. Thus while there is some instability the moisture looks to already have moved past our area and off to the east thus reducing the forcing needed to produce stronger storms. Looking at the Hi-Res models, particularly the FV3 and the NAM, they both show very little in the way of convective precipitation. Additionally while looking at recent model guidance all 3 of our reliable models have trended down in not only precip amounts but also chances of precip for this storm system so have capped pops at 20-30% for most areas north of San Antonio with the exception being our extreme northeastern counties with pops generally around 40-45%. The next storm system, #2 is set to arrive sometime Thursday afternoon into Thursday evening and looks to swing through our area via a closed low pressure system in northern Texas moving northeast into Missouri. As it does so Global models paint a cold front extending from the low back into South-Central Texas with a warm front moving through the area earlier in the day. This setup looks a little bit more promising especially with the triple Low setup and as such the Global models seem to agree with both the GFS and Euro being consistent in timing but inconsistent in strength. The GFS once again is leaning towards lighter precip amounts compared to the bullish amounts the Euro is spitting out. Decided to go with a blend between the two as the previous couple runs show some level of consistency with forcing and enough moisture noted along with fairly good levels of vorticity showing up. Feel there is certainly a better chance that we could see more moisture out of this system then the previous one. However, as we have seen recently its best not to get our hopes up as amounts tend to trend down as higher Hi-Res model guidance comes in and as we get closer to the event. Lastly, our third system looks to arrive sometime Friday night into Saturday morning with chances for more showers and storms as a cold front looks to slice through our area. As with the previous systems the western part of our CWA looks to completely miss out on any precip while our eastern areas look to receive repeated rounds of showers and storms. && .AVIATION... (12Z TAFS) Issued at 527 AM CST Sun Dec 22 2024 Scattered mostly MVFR cigs are forming over much of the higher terrain along and north of Del Rio to San Antonio with a brief spell of IFR cigs forecast for DRT later this morning. SAT/SSF should see most of the day in MVFR cigs but AUS may only see a brief period as drier air could still mix in from the SE since a dry NE surface wind continues over SE TX. Onshore winds should be more uniform by this evening, and AUS will likely get closer to falling near the same time as SAT/SSF into MVFR to IFR. The NAM model has performed slightly better than the GFS in the lower level moisture return, so will keep with the IFR prevailing in the final hours of the TAF periods. Some light showers could form tonight between DRT and SAT, but low model QPF values would suggest not much of an impact on the respective airports. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 67 54 75 60 / 0 20 10 10 Austin Bergstrom Intl Airport 68 55 76 61 / 0 20 10 10 New Braunfels Muni Airport 69 55 77 60 / 0 20 10 0 Burnet Muni Airport 64 54 72 59 / 0 10 10 10 Del Rio Intl Airport 69 59 76 58 / 10 20 10 0 Georgetown Muni Airport 66 54 74 60 / 0 10 10 10 Hondo Muni Airport 67 57 75 60 / 10 20 20 0 San Marcos Muni Airport 68 54 76 60 / 0 20 10 0 La Grange - Fayette Regional 69 52 76 59 / 0 10 10 0 San Antonio Intl Airport 68 58 75 62 / 0 20 20 0 Stinson Muni Airport 70 58 77 62 / 0 10 10 0 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Short-Term...18 Long-Term...CJM Aviation...18
No recent Short Term Forecast (NOW) has been issued for NWS Austin/San Antonio CWA (EWX).
Special Weather Statement Issued: 12/17/2024 10:00:02 PM UTC