513 FXUS64 KEWX 160101 AAA AFDEWX Area Forecast Discussion...UPDATED National Weather Service Austin/San Antonio TX 801 PM CDT Sat Oct 15 2022 ...New UPDATE... .UPDATE... Issued at 755 PM CDT Sat Oct 15 2022 Elected to add some patchy fog across the coastal plains from late overnight into Sunday morning. Additionally, with a slightly faster timing of the cold front across the region Sunday evening/night, I have elected to lower the temperatures during Monday for areas that are mainly located along and north of the I-35 corridor, where the temperatures will fall into the upper 50s and low to mid 60s by the late afternoon. Kept rain chances the same as the previous package at this time. && .SHORT TERM... (Tonight through Sunday night) Issued at 157 PM CDT Sat Oct 15 2022 Synopsis/Mesoanalysis: Split flow continues to prevail over much of the CONUS. The northern stream, associated with an upper disturbance centered just to the southwest of Hudson Bay, swings east-southeast from the northern Rocky Mountains into the Ohio and Tennessee River Valleys. The accompanying southern stream speed max spreads zonally from the base of a cutoff low centered off the Baja California coastline into the lower Mississippi Valley and central Gulf Coast. The two features will continue to persist through tomorrow afternoon and evening, likely beginning to interact to some extent from the southern Plains east into the southeastern US. In the lower levels, a baroclinic zone is evident across central Oklahoma east into the Ozark Plateau. The boundary should serve as a focus for convective initiation across this region later today, with attendant outflows driving the front into the Edwards Plateau through tomorrow morning and afternoon. Tonight: Have largely removed previous slight chance mentions of showers and thunderstorms predawn over portions of the Rio Grande Plains and southern Edwards Plateau. The impulse which will facilitate activity should track largely north and west of the region, keeping precipitation chances confined mostly to the MAF and SJT CWAs. An isolated shower or storm can't be completely ruled out over far northern Edwards and Val Verde Counties, where a sliver of precip probabilities remain. The vast majority (if not all) of the area will remain dry, with low stratus developing nocturnally once again. Lows should thus remain in the upper 60s and low 70s across the area. Tomorrow: Expect highs in the 80s and low 90s. Thanks in large part to outflow from tonight's convection over the Red River Valley and ArkLaTex, the cold front mentioned above will begin to approach from the north by late afternoon/early evening. Likely due to 1) stubborn low stratus in the morning and 2) residual mid-upper level cloud debris from overnight and early morning thunderstorms to our north, convection allowing models continue to suggest little PM surface destabilization and attendant shower/storm development along the front as it approaches. Have thus trimmed precip probabilities back through sunset in light of these trends, though an isolated thunderstorm can't be entirely ruled out closest to the likely surface position of the boundary from the southern Edwards Plateau east into Hill Country. Have continued slight chance thunder mentions in these regions. Tomorrow Night: This continues to be a period that bears close watching. Convective development appears likely near and after 00Z over the lower Trans-Pecos as the speed max connected to the Baja cutoff begins to overspread the region. Activity should spread east into the Rio Grande Plains and Winter Garden moving deeper into the overnight hours, with lighter/more scattered precip possible over Hill Country and the the I-35 corridor. The cold front will concurrently be approaching and entering the southwestern CWA. Combined with nocturnally-amplifying east to southeast low level flow and attendant moisture advection, the forcing from the front and any impulses embedded within the mid level speed max could create a favorable setup for multiple episodes of convection over portions of the Rio Grande Plains and Winter Garden through the predawn hours Monday. Given the presence of 1.50-2.00" precipitable water values pooled along the front, as well as a nearly antiparallel alignment between the low and mid level flow, heavy rainfall and backbuilding/training would be possible in said setup. Lots of model spread continues to exist regarding accumulations, particularly between the CAMs and global ensembles, so we will refrain from suggesting any specific totals in this discussion. WPC has included much of the Rio Grande Plains and portions of the Winter Garden in a slight risk in its D2 Excessive Rainfall Outlook in light of this potential. We will continue to closely monitor forecast trends and amend the forecast as necessary. && .LONG TERM... (Monday through Saturday) Issued at 157 PM CDT Sat Oct 15 2022 Active southwest flow aloft along with some forcing along a cold front will result in active weather along with a good chance of rainfall for portions of south central Texas. With a fairly shallow cold front near the surface and southeasterly winds initially in place around 850mb early Monday morning, scattered to numerous showers and thunderstorms are expected. The models continue to show the most favorable setup for rainfall will occur out west across the southern Edwards Plateau and Rio Grande plains. We will keep rain chances generally at or above 70% for the mentioned areas throughout the daytime hours on Monday. With marginal shear and instability in place, a strong to severe storm or two can't be completely ruled out mainly over the Rio Grande plains south of Del Rio. Gusty winds and marginally severe hail are the main concerns. In addition, some locally heavy rainfall may occur across the Rio Grande plains as moist southeast to easterly flow just above the frontal layer continues through most of the daytime hours. Farther east into the Hill Country and along/east of the I-35 corridor, the setup for heavy rainfall does not appear too favorable at this time. We do expect some scattered showers and storms, but forecast rainfall amounts will be significantly lower compared to values along the Rio Grande. For Monday night, northeasterly flow in the low-levels begins to deepen and this will result in drier and more stable air being advected into the region. We will begin to show much lower rain chances over our northern areas, with higher rain chances farther south into the Winter Garden region. In addition, the focus for any strong storms and locally heavy rainfall should be mostly south of our region by late evening. Most areas will remain dry on Tuesday as gusty northeast winds behind the cold front spread across all of south central Texas. Much cooler high temperatures are in store with highs only in the lower 60s to near 70s. Cloud cover will also decrease from north to south as the day progresses. Low temperatures for Tuesday night into Wednesday morning will be quite chilly with some upper 30s likely in the Hill Country and mainly 40s expected elsewhere. Surface high pressure remains over the area Wednesday and this will result in highs in the upper 60s to lower 70s. South to southwesterly winds in the low-levels return on Thursday and highs will rebound back into the lower 70s to lower 80s. Southerly flow in the low-levels continues to strengthen on Friday and Saturday, with temperatures getting back closer to climatological normals. && .AVIATION... (00Z TAFS) Issued at 640 PM CDT Sat Oct 15 2022 VFR flight conditions continue into tonight before deteriorating to IFR to MVFR levels during the overnight into Sunday morning with low ceilings. Couldn't rule out some patchy fog for the I-35 sites but likely will be more concentrated across the coastal plains. Ceilings improve to VFR levels from Sunday afternoon into Sunday evening. A stronger autumn cold front moves into South-Central Texas in the 24 to 30 hour TAF range and have inserted a PROB30 group at KAUS for introduction for possible -TSRA. Otherwise, I have elected to keep any precipitation mentions out of the rest of the TAF sites through this TAF period. Light to moderate southeasterly winds continue with winds then turning more easterly to northeasterly Sunday evening at KAUS and KSAT with the approach and passage of the aforementioned front. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 72 91 64 68 / 0 20 50 60 Austin Bergstrom Intl Airport 68 90 62 69 / 0 20 50 60 New Braunfels Muni Airport 71 92 66 71 / 0 10 50 60 Burnet Muni Airport 69 87 60 65 / 0 30 60 60 Del Rio Intl Airport 71 87 67 70 / 0 20 80 90 Georgetown Muni Airport 70 88 61 66 / 0 20 50 60 Hondo Muni Airport 70 92 69 72 / 0 0 60 70 San Marcos Muni Airport 70 91 66 70 / 0 10 50 60 La Grange - Fayette Regional 69 92 67 74 / 0 20 50 50 San Antonio Intl Airport 71 91 68 71 / 0 10 50 60 Stinson Muni Airport 72 93 70 73 / 0 10 50 60 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Short-Term...Brady Long-Term...Platt Aviation...Brady