Area Forecast Discussion
Issued by NWS Austin/San Antonio, TX
Issued by NWS Austin/San Antonio, TX
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856 FXUS64 KEWX 121959 AFDEWX Area Forecast Discussion National Weather Service Austin/San Antonio TX 159 PM CST Tue Nov 12 2024 ...New SHORT TERM, LONG TERM, FIRE WEATHER... .SHORT TERM... (Tonight through Wednesday night) Issued at 106 PM CST Tue Nov 12 2024 Upper air analysis this morning showed the sub-tropical ridge bulging up from the Gulf with a trough from UT/CO to Baja California. The flow over Texas was from the southwest. Low level winds are from the southeast with high pressure centered to the northeast of the region. The airmass is warm and moist with temperatures in the 70s and 80s and dewpoints in the 60s. The upper trough will move into west Texas and then lift out to the northeast turning the flow to zonal. The low level flow will remain southeasterly tonight. With the weather pattern staying about the same tonight will be similar to last night. Temperatures will be within a couple of degrees of this morning`s lows. A cold front will move through West Texas tonight reaching our northwestern border by morning. This front will move across our CWA during the day Wednesday. Without much moisture or upper support, the front will move through dry. Winds will shift to the northwest bringing cooler, drier air. High temperatures Wednesday will be dependent on when the front passes any particular location. Highs over the northwest will be a few degrees cooler while the southeast will be a little warmer. Dewpoints will drop 20-25 degrees from this afternoon to Wednesday after over the northern and western part of the CWA. See the Fire Weather discussing below for more on this. The cooler air will continue to filter in Wednesday night and lows Thursday will be around 10 degrees cooler. && .LONG TERM... (Thursday through Tuesday) Issued at 106 PM CST Tue Nov 12 2024 A surface high will be situated over the Hill Country early Thursday, resulting in good radiational cooling with dry air in place behind Wednesday`s cold front. Temperatures will start out in the 40s and lower 50s with a more comfortable forecast for Thursday afternoon. Highs should be closer to normal for mid-November, but still some 3-5 degrees above normal with highs in the mid to upper 70s. The "cooldown" won`t last long as Pacific cold fronts don`t typically bring as much cool air to the table as Polar fronts do. We`ll get one more cool/borderline chilly morning Friday before highs climb back into the upper 70s/lower 80s in the afternoon as southeasterly winds return on the backside of the departing surface high. Low level moisture will be on the increase this weekend as we turn our attention to the west coast. A powerful storm system will plow through the Desert Southwest, centering as far south as the southern Arizona/southern New Mexico border late Sunday. Breezy southerly flow will ramp up ahead of this new storm system, which will initially send a Pacific front through our CWA on Monday afternoon. Showers and thunderstorms will develop along this boundary, with a low chance to be strong to severe. Slightly cooler air filters in behind this front, but then we wait for the stronger front, this time, of Polar origin, to push through the region next Tuesday. It is worth noting that nearly every member of the ECMWF ensemble and GFS ensembles depict this frontal boundary, so confidence has increased significantly in a large scale pattern change for the beginning of next week. While we will certainly take the cooler weather as the last month+ of heat and dry air has been unwelcome. However, rain chances look rather slim with this boundary, so we`ll have to wait longer to see if this newer pattern can bring better rain chances back into the forecast. && .AVIATION... (18Z TAFS) Issued at 1132 AM CST Tue Nov 12 2024 All terminals will have only few to scattered clouds through the next TAF period. Southeasterly winds at less than 10 kts will continue through the afternoon and early evening and then become light this evening. Winds will become southwesterly Wednesday morning. A cold front will move through the region during the afternoon turning the winds to the northwest. && .FIRE WEATHER... Issued at 106 PM CST Tue Nov 12 2024 A dry, Pacific cold front will move through south-central Texas on Wednesday with fire weather concerns for some areas behind it. Relative humidity will drop below 30% across the area along and west of I-35 and below 20% over the southern Edwards Plateau and most of the Rio Grande Plains. Winds will also be breezy behind the front. The combination of low RH and breezy winds will likely lead to near critical fire weather conditions over the west with elevated conditions over the Hill Country. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 59 86 51 76 / 0 0 0 0 Austin Bergstrom Intl Airport 57 86 51 76 / 0 0 0 0 New Braunfels Muni Airport 60 87 52 78 / 0 0 0 0 Burnet Muni Airport 59 81 48 74 / 0 0 0 0 Del Rio Intl Airport 66 85 50 79 / 0 0 0 0 Georgetown Muni Airport 58 84 49 74 / 0 0 0 0 Hondo Muni Airport 61 85 51 78 / 0 0 0 0 San Marcos Muni Airport 58 85 50 76 / 0 0 0 0 La Grange - Fayette Regional 55 85 50 76 / 0 0 0 0 San Antonio Intl Airport 62 85 54 78 / 0 0 0 0 Stinson Muni Airport 62 87 55 79 / 0 0 0 0 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Short-Term...05 Long-Term...MMM Aviation...05