At this exact hour two years ago, I published this Facebook post regarding the tropical wave that had been upgraded to a depression:
Harvey had organized and my immediate concern was that the synoptic situation -- where all the highs and lows and fronts were located -- compared eerily to the same synoptic situation in 2001 when TS Allison moved ashore. Here's the Allison situation:
And when Allison got stuck, I watched that June Friday night into Saturday as 36" to 42" of rain fell over 12 hours. Seemingly, the bar for flooding in Houston had been set, but now we had a major contender.
The National Hurricane Center forecasted a very slow movement of Harvey and the slower a storm moves, the more rain it can drop in one spot. So while the Storm Prediction Center already had a 16" rain bull's-eye over us, warm tropical air can hold double the rainfall, so amounts reaching Allison's threshold were certainly possible.
By Thursday, the forecast had slowed Harvey even more and I took a deep breath to warn people that 50" of rain would be possible over the weekend.
After the Memorial Day and Tax Day floods, knowing the psychological impact we'd already been through, that kind of forecast was not an easy one to make. Let's face it, if the forecast busted after constant coverage and predicting four feet of rain, everyone might be relieved I was wrong, but I'd look pretty silly. The models though were in good agreement for huge rainfall and there was my old rule of thumb: 100 divided by the speed of the storm = rainfall. So, Harvey moving 2 mph would equal 50" of rain. Possible. Somewhere. And just like Allison.....
We all experienced the heart-wrenching results. The four-day rainfall amounts, most of which fell Saturday night into Sunday beating even the most mind-blowing forecast:
Not only an Allison, but a widespread, all-encompassing Allison.
And with a bigger tragedy comes bigger lessons. We all learned something: our personal vulnerability to nature, our spirit when called on to unify, our human capabilities of kindness and empathy. As a professional, I've always known never to underestimate the power of weather. What I learned was to never underestimate the power of people to fight back and be there for each other.
We continue to show remarkable resiliency to this storm. For many, it's still not over and for the rest of us, we have an obligation to push for the future and prevent this from happening again.