November 17, 2003: A Day that Changed My Life

A look back on the day from a meteorological point-of-view, and a little bit from what I remember.

Meteorological Setup

On the morning of November 17, 2003, a deep, positive-tilting upper-level trough sat across the southwestern US and the Baja Peninsula. The base of the trough was the point where split flow between the polar jet and the subtropical jet merged. Also, the trough was beginning to eject across northern Mexico and southwest Texas, as the jet streak was downstream from the trough axis. This, along with difluent aloft in the exit region of the jet allowed for deep-layer ascent across southern and southeastern Texas. This upper-level support would be a major key to supporting convection in the warm sector prior to the approach of a cold front that would push through later that night.

300mb-level analysis at 12Z on November 17, 2003.

At the surface, conditions were sufficient for organized convection. Shown from the surface observations at 12Z, dewpoint temperatures were well into the 70s across much of south and southeast Texas. Winds were also backed towards the southeast at the surface, which aided in supporting the veering wind profiles.

Surface observation at 12Z on November 17, 2003.

A large shield of precipitation developed along the Gulf coast and was moving into the Houston metro area. While the Houston/Galveston NWS office does not launch weather balloons, the Corpus Christi 12Z ROAB sounding suggested sufficient wind shear, moisture, and instability for supercells.

Sounding profile from Corpus Christi, TX at 12Z on November 17, 2003.

With how messy the convection was in this environment, it was evident that any storms that exhibited supercell characteristics would likely be embedded with other convection. Also, with the advection of moisture from the Pacific, it was evident that this event was also going to produce lots of rainfall over widespread across the southern Plains and into the Ozarks and Piney Woods. By 17Z, a MCS with embedded supercells on the southeast side of the shield of rain moved into the Houston metro producing heavy rainfall and several tornadoes.

Reflectivity image at 1700Z of ongoing storms across southeast Texas on November 17, 2003.

These storms began to train over the southern and eastern sides of the metro producing significant rain totals in these areas. Along the middle and upper Texas coastlines, brief tornadoes continued to spin up along the leading edge of the line. By the afternoon and evening hours, this large complex of convection moved northeast and became subsevere; however, deep-layer ascent from difluence in the exit region of the jet in association with the ejecting trough aided in another line of training supercells developing in the warm sector on the eastern side of the city. Also, a line of storms along the surging cold front had matured and was producing torrential rainfall. Analysis of the Corpus Christi and Lake Charles 00Z ROAB soundings show that instability and wind shear were still conducive for organized storms (particularly Lake Charles). In regard to limiting factors for more robust convection, radar showed around this time that storm mode was working against organized convection as storms were progressing parallel to the advancing cold front. Ongoing storms around 0230Z produced more tornadoes and only exacerbated the flooding situation within the city of Houston.

300mb-level analysis at 00Z on November 18, 2003.

Sounding profile from Lake Charles, LA at 00Z on November 18, 2003.

Reflectivity image at 0230Z of the two lines of storms affecting the Houston metro on November 18, 2003.

By 07Z, the most significant of the convection finally pushed east of the Houston metro area, and stratiform precipitation developed behind the cold front. Fortunately, this precipitation was light and scattered, so it did not significantly add to the rainfall totals within southeast Texas.

Reflectivity image of the line of convection and stratiform rain at 12Z on November 18, 2003.

The Impacts

The National Weather Service in Houston/Galveston put together a graphic that describes the combined impacts from the tornado outbreak and flooding along with reflectivity and velocity radar images of two of the four F2 tornadoes that struck the forecast area. 

https://twitter.com/nwshouston/status/799481909323694080

In total, 24 tornadoes hit the NWS Houston forecast area, most impacting the southern and eastern portions of the Houston metro. Arguably though, the flooding was the more impactful as it was widespread and destructive though the duration of this event. Training convection, most being at least somewhat organized, produced significant rain totals in a very short period of time. While not necessarily on the same magnitude of Tropical Storm Allison a couple years prior, parts of the city were inundated with feet of water, causing extensive impacts to life and property.

Why is this event important to me?

Personal memories from this event are a bit scattered for me as this event occurred on my 6th birthday. I remember we had just moved to a new house outside of Beltway 8 not even a month before. I remember being rushed out of my Kindergarten classroom to get picked up by mom about 3 or 4 hours earlier than normal (I believe schools let out early, but I can't confirm this). I remember my dad being stuck on an overpass on Beltway 8 for several hours, and he wasn't able to come home until well after midnight. This tornado outbreak and flooding event is the whole reason why I wanted to pursue a career in meteorology. My parents tell me that while I had some interest in the weather in passing, this event was certainly a catalyst for me becoming obsessed with meteorology. Not everyone has a story as to how they found their passion, this experience definitely sparked my passion for the weather. It's funny to think that, at a point, I was absolutely terrified of any kind of storm. Now that fear has evolved into a fascination. While records are pretty spotty prior to 2004, it's always exciting to find little tidbits of information that involved the severe weather/flooding event that impacted Houston on November 17, 2003. Along with that, now that I have almost completed my meteorology degree at the University of Oklahoma, I can now look at various kinds of maps analyses and understand why things unfolded like they did on this day. Had the atmosphere decided not to line things up perfectly for a prolific tornado and flooding event over the Houston area on that day, who knows where I'd be today.