San Antonio weather has taken a dangerous turn early this Wednesday. If you’re checking forecasts right now, you’re likely facing urgent alerts: a Severe Thunderstorm Warning remains active until 5:00 AM CDT for Bexar, Comal, and Kendall Counties, and a Flash Flood Warning is in effect until 7:30 AM. The National Weather Service reports torrential rain dropping 1-3+ inches, triggering life-threatening flooding across creeks, streets, and underpasses. Travel is strongly discouraged – if you must go out, extreme caution is vital. This abrupt shift ends May’s extreme drought and record heat, but replaces it with significant hazards. This guide delivers critical, real-time updates on the ongoing severe San Antonio weather, explains the immediate threats (large hail, damaging winds, flash flooding), provides actionable safety steps, and details the evolving forecast through the weekend. Understanding these dynamics isn’t just about comfort; it’s crucial for safety as this volatile pattern continues.
Immediate Threat: Breaking Down the Active Warnings
San Antonio weather turned perilous overnight. As of 4:40 AM CDT Wednesday, the National Weather Service (NWS) has issued dual, overlapping warnings impacting the metro area and surrounding Hill Country.
- Severe Thunderstorm Warning (Until 5:00 AM CDT):
- Counties: Southeastern Kendall, Northwestern Bexar, Southwestern Comal.
- Threats: Damaging winds up to 60 mph, quarter-sized hail (1 inch diameter), frequent lightning, torrential downpours.
- Action: Move indoors immediately! Stay away from windows. Avoid using corded electronics. If driving, try to find a safe, sturdy shelter. Do not take shelter under highway overpasses.
- Flash Flood Warning (Until 7:30 AM CDT):
- Counties: Large part of Bexar County, parts of Kendall and Comal Counties.
- Threat: Additional rainfall of 1-3 inches possible, causing rapid and dangerous flooding of creeks, streams, urban areas, highways, streets, and underpasses. Many roads are likely already impassable.
- Action: TURN AROUND, DON’T DROWN. Do NOT attempt to drive through flooded roadways. The depth and current are deceptive, especially at night. Seek higher ground immediately if in a flood-prone area. Abandon your vehicle if it stalls in rising water.
Understanding the Flash Flood Danger
Flash flooding is the most immediate and deadly threat accompanying this severe San Antonio weather event. Here’s why it’s so critical:
- Topography Matters: San Antonio’s terrain, coupled with urban development, creates perfect flash flood conditions. Hard surfaces (roads, parking lots, roofs) prevent water absorption, causing rapid runoff into low-lying areas and creek basins.
- “Box Canyon” Effect: The Texas Hill Country northwest of San Antonio acts like a funnel. Heavy rain falling over the elevated, rocky terrain drains rapidly southeastward into the Bexar County lowlands, overwhelming creeks like the San Antonio River, Salado Creek, and Leon Creek very quickly.
- Nighttime Peril: As emphasized by the NWS, traveling at night during flash floods is exceptionally dangerous. Headlights reflect off water, making it nearly impossible to judge depth or see if the road has been washed out underneath. Just 12 inches of moving water can sweep away most vehicles.
- Hidden Hazards: Floodwaters hide debris, downed power lines, and sharp objects. Currents are stronger than they appear. Water can rise incredibly fast, trapping people in homes or vehicles.
Essential Flash Flood Safety Steps:
- Do NOT Drive: This cannot be stressed enough. Over half of flash flood fatalities occur in vehicles. Find an alternate route or delay travel.
- Know Your Zone: Are you near a creek, river, or known low-water crossing? Identify safe higher ground now.
- Heed Barricades: They are there for your protection. Driving around them is illegal and deadly.
- Home Preparation: If in a flood-prone area, move valuables to higher floors. Have an evacuation plan and kit ready.
- Stay Informed: Follow the Bexar County Flood Warning System and NWS updates.
From Drought Deluge: The Dramatic Weather Shift
This severe San Antonio weather event represents a stunning reversal of the recent climate pattern.
- The Dry Precedent: For much of May, South Texas baked under extreme drought conditions (U.S. Drought Monitor) and record-breaking heat. Rainfall deficits mounted, stressing landscapes and increasing fire danger.
- The Pattern Flip: A significant shift in the upper-level weather pattern over the past few days allowed deep, Gulf moisture to surge inland. Combined with approaching upper-level disturbances and daytime heating, this created the volatile atmosphere capable of producing the intense thunderstorms we’re experiencing now.
- Silver Lining (with Caution): While bringing hazards, this rain is desperately needed to alleviate drought. However, the intensity and speed of the downpours falling on hardened, dry ground significantly increase the runoff and flash flood risk – the soil simply can’t absorb it fast enough. It’s a classic “too much, too fast” scenario.
San Antonio Weather Forecast: What’s Next?
The active weather San Antonio faces won’t completely vanish after this morning’s storms. Here’s the evolving outlook:
- Wednesday (Today):
- Morning (Now – ~11 AM): Showers and thunderstorms likely (50% chance), especially early. Lingering heavy rain and flooding remain the primary concerns. Gusty winds and small hail possible in any stronger storm. Travel remains hazardous due to flooding.
- Late Morning / Afternoon: A break in the widespread activity expected. Clouds may thin, allowing some peeks of sunshine. Highs warming slowly to the mid-80s. Humidity remains very high.
- Late Afternoon / Evening (~4 PM onward): Scattered showers and thunderstorms redevelop (40% chance). The Storm Prediction Center has placed San Antonio under a Marginal Risk (Level 1 of 5) for severe storms. Isolated storms could again produce damaging winds (60+ mph) and quarter-sized hail. Heavy downpours could cause renewed flooding, especially in areas already saturated.
- Overnight: Storm chances decrease, becoming more isolated. Lows in the low 70s.
- Thursday:
- Rain chances decrease but aren’t zero (30% chance). Expect a mix of clouds and sun. Warm and very humid again. Highs in the upper 80s. Heat index values likely reaching the mid- to upper 90s. Scattered storms possible late afternoon/evening, primarily north/east of the city.
- Friday:
- A weak cold front pushes through during the morning. This will bring a slight drop in humidity and temperatures. Highs expected in the mid-80s. A 20% chance of a shower or storm near the front passage. Drier air filters in behind it.
- Weekend Outlook:
- Saturday: The coolest morning, with lows possibly dipping into the upper 60s. Mostly sunny skies dominate. Highs rebound to the upper 80s. Lower humidity (by Texas summer standards!) makes it feel pleasant.
- Sunday: The warming trend continues. Mostly sunny and hotter, with highs pushing back into the low 90s. Humidity starts to increase again. Rain chances look very low.
5. Essential Safety & Preparedness for San Antonio Weather Extremes
Living in South Texas means being prepared for dramatic swings in San Antonio weather – from drought and heatwaves to severe thunderstorms and floods. Here’s your action plan:
- Build Your Emergency Kit: Include water (1 gal/person/day for 3 days), non-perishable food, first-aid kit, medications, flashlight + extra batteries, battery-powered or hand-crank NOAA Weather Radio, multi-tool, cash, important documents, phone chargers/power banks.
- Have Multiple Alert Sources: Enable Wireless Emergency Alerts (WEA) on your phone. Get a NOAA Weather Radio. Follow trusted local news and NWS social media (@NWSSanAntonio).
- Know Your Evacuation Routes: Plan how to get to higher ground from home, work, and school.
- Protect Your Property: Clear gutters and drains. Consider flood insurance (standard homeowner’s insurance does NOT cover flooding – FEMA FloodSmart). Secure outdoor furniture before storms.
- Heat Safety: When extreme heat returns (likely soon!), know the signs of heat exhaustion/stroke. Stay hydrated, limit strenuous outdoor activity during peak heat (10 AM – 4 PM), never leave people or pets in vehicles.
- Drought Awareness: Follow local water restrictions. Be fire-wise – avoid activities that could spark wildfires during dry periods.
Conclusion
The San Antonio weather this morning demands immediate attention and caution due to ongoing severe thunderstorms and dangerous flash flooding. Remember: Turn Around, Don’t Drown is not just a slogan; it’s a lifesaving rule. While this rain brings much-needed relief from May’s drought, its intensity creates significant hazards. Stay vigilant through Wednesday as more scattered storms are possible, and prioritize safety above all else. The forecast shows a brief respite in humidity late week before temperatures climb back towards the 90s this weekend. By understanding the unique challenges of weather San Antonio presents – from flash floods fueled by Hill Country runoff to intense summer heat – and proactively preparing, you and your family can stay safer through whatever extremes come next. Sign up for local alerts today.
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FAQs:
How does the National Weather Service determine when to issue a Severe Thunderstorm Warning vs. a Watch for San Antonio weather?
A Watch (issued by the Storm Prediction Center) means conditions are favorable for severe storms (capable of 58+ mph winds and/or 1″ hail) in a broad area, typically for several hours. It’s your signal to prepare. A Warning (issued by your local NWS office, like Austin/San Antonio) means radar or spotters have detected a severe storm producing those threats right now in a specific area. This demands immediate action to protect life and property. Their meteorologists use advanced radar technology (Doppler, dual-polarization), satellite data, lightning detection, and trained spotter reports to make these critical, real-time decisions.
Why is flash flooding such a persistent and dangerous threat in the San Antonio area specifically?
San Antonio’s unique geography is a major factor. The city sits at the confluence of multiple creeks draining the steep, rocky terrain of the Texas Hill Country northwest of the city (“Flash Flood Alley”). When heavy rain falls over this elevated, less permeable ground, water rushes rapidly downhill with incredible force into the Bexar County basin. Combined with significant urban development (increasing impervious surfaces like concrete) and the city’s network of creeks and rivers (San Antonio River, Salado, Leon, etc.), this creates a perfect setup for rapid and devastating flash floods. Historical events tragically underscore this vulnerability. Mitigation efforts like the San Antonio River Tunnel Project aim to reduce risk, but vigilance remains essential.
