Area Forecast Discussion
Issued by NWS Austin/San Antonio, TX
Issued by NWS Austin/San Antonio, TX
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336 FXUS64 KEWX 170750 AFDEWX Area Forecast Discussion National Weather Service Austin/San Antonio TX 250 AM CDT Mon Jun 17 2024 ...New SHORT TERM, LONG TERM... .SHORT TERM... (Today through Tuesday) Issued at 216 AM CDT Mon Jun 17 2024 A mid-level trough over the western Gulf has pushed the subtropical ridge toward the west over northern Mexico. Southeasterly flow in the low levels has continued over the last 24 hours. A warm, moist airmass remains in place over South Central Texas. The upper trough over the Gulf will continue to push slowly to the west while the low level flow continues from the southeast. The weakening of the ridge will allow for possible showers and thunderstorms over the Coastal Plains counties today. A little more cloudiness today will keep temperatures a few degrees lower than yesterday. Convection should end with the loss of daytime heating. There is a small chance for some streamer showers overnight, but chances are so low that we will not include any mention in the forecast. Overnight lows will be similar to today. As the Gulf trough approaches the coast rain chances will push farther inland Tuesday. Slight chances for showers and thunderstorms will reach I-35 during the afternoon with better chances over the Coastal Plains. Temperatures will drop another couple of degrees. && .LONG TERM... (Tuesday night through Sunday) Issued at 216 AM CDT Mon Jun 17 2024 The latest NHC forecast for the formation of a tropical system in the southwestern Gulf of Mexico has a 60 percent chance in the next 48 hours, and a 70 percent chance over the next 7 days. PWATS continue to increase overnight Tuesday into Wednesday with all of the area seeing values over 2 inches by Wednesday afternoon. This moisture and disturbance will bring increasing shower and thunderstorm chances to the area from east to west through the day on Wednesday with these chances continuing through much of the day Friday. There still remains considerable differences in exactly how this system will track, which in turn leads to many solutions for rainfall amounts from mid to late week. The NBM gives roughly a 30 to 60 percent chance for all of South Central Texas to see two inches or greater rainfall through Friday which remains similar to the GEFS ensemble probabilities. The latest ECMWF ensemble guidance gives only about a 40 to 60 percent chance for an inch or more for our southernmost tiers of counties at this time, so quite a difference from other guidance. GEFS probabilities for 4 or more inches of rain during this time along and east of I-35 remain at 30 to 40 percent. Taking all of this into consideration, there looks to be a high potential most of the area will see some rain mid to late week, with a medium potential for heavy rain which could lead to flooding or flash flooding. WPC has increased the the potential for excessive rainfall to a level 3 of 4 for portions of the coastal plains and I-35 corridor, with a level 2 of 4 elsewhere for Wednesday into Thursday morning. The day 4 forecast (Thursday into Friday morning) remains similar to yesterday with the level 2 of 4 risk shifting across the western half of the area. Cloudy conditions will lead to much cooler than normal temperatures during this time with highs mainly in the 80s Wednesday and Thursday. A warming trend may be seen again Friday into the weekend, although forecast temperatures still remain below 100 degrees for this timeframe. Rain chances decrease Friday night into Saturday morning for much of the area, with chances returning for the coastal plains each afternoon this weekend. && .AVIATION... (06Z TAFS) Issued at 1016 PM CDT Sun Jun 16 2024 The sea breeze has made it into KAUS/KSAT/KSSF, with gusty southeasterly winds this evening. These winds should slowly drop off to light to moderate by 08Z. KAUS/KSAT/KSSF will see MVFR CIGS by 08Z and lasting until 16Z Monday. KDRT CIGS will be higher and only from 10-14Z. There may be -DZ or -SHRA around KAUS/KSAT/KSSF around daybreak and possibly again by early evening Monday, but low enough chances to leave out of the TAFs at this time. Expect a repeat Monday evening with gusty southeasterly winds as the sea breeze makes it to the I-35 corridor around sunset. Otherwise, expect MVFR cigs at all sites by 03-04Z. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 76 92 74 81 / 0 20 20 60 Austin Bergstrom Intl Airport 75 92 74 81 / 0 20 20 60 New Braunfels Muni Airport 76 94 74 81 / 0 20 20 70 Burnet Muni Airport 75 90 73 81 / 0 10 10 50 Del Rio Intl Airport 80 101 78 93 / 0 0 0 30 Georgetown Muni Airport 74 90 72 79 / 0 10 20 60 Hondo Muni Airport 76 95 75 83 / 0 10 10 60 San Marcos Muni Airport 74 92 73 81 / 0 20 20 70 La Grange - Fayette Regional 76 90 74 81 / 10 30 30 70 San Antonio Intl Airport 77 94 74 82 / 0 20 20 60 Stinson Muni Airport 78 95 76 83 / 0 20 20 70 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Short-Term...05 Long-Term...27 Aviation...05