Harvey’s Impact Expands And Signs of Fall Are Showing Up

We have been witness to one of the worst flooding disasters in U.S. history these past several days. Starting Saturday, heavy bands from Harvey started to really lash the Houston area with up to 6” per hour rainfall rates. Since that time nearly 40” of rain has occurred in parts of the metro area, just 10” shy of Houston’s YEARLY average rainfall total. While the full impacts there are still unknown, we do know Harvey’s impacts will continue to expand.

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                Tropical Storm Harvey has moved off-shore into the Gulf of Mexico yet again. Fortunately, dry air is entraining around the southern half of its circulation, limiting its strength (as shown above). If we had more symmetry of rain and storms around its center, Harvey could rapidly strengthen towards hurricane strength again given the warm waters and expected time just off the Texas coast.  In any case, the wind threats are certainly secondary to the prolific rain totals through the end of the week (shown below). The heaviest rain shield likely remains over southeast Texas and expands into Louisiana further. If we had 40+ mph winds to that, we could easily see numerous trees going down thanks to wet soils (understatement of the year). That could in turn lead to more power outages for that area as Harvey’s center drifts east and makes a second landfall not far from Galveston or just east.

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                After days of meandering, Harvey will finally latch onto something of a steering current. Our computer models are coming into better agreement in lifting in north-northeast starting midweek and pulling it out of the storm-weary coastal region. As of now, it appears we’ll only see minimal impacts here in Oklahoma as Harvey takes a path into Arkansas. However, a shift west in that track could bring a couple inches of rain to parts of Green Country. Assuming that doesn’t occur, at most we’ll see more cloud cover, the outer bands of rain mainly southeast of Tulsa and a moderate breeze out of the northeast. This would occur for the second half of the week into the start of the holiday weekend.

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                Speaking of our holiday weekend, Labor Day isn’t looking half bad for us! Aside from Harvey’s near-miss, we’ll continue to enjoy slightly below normal temperatures and some sunshine. A weak disturbance could bring a little rain this weekend, but I don’t see any major interruptions to outdoor plans. Our high temperatures could top 90°, but that’s still a treat compared to many other Labor Day weekends around here.

                In the longer range outlook, the jet stream pattern becomes more amplified, sending a deep trough over the eastern half of the country. That will bring down a cold front, ushering in perhaps our first real taste of fall by the first full week of September. We often see this occur early in September, but it usually follows much hotter weather than what we’ve had over most of August.  In any case, this will trend our temperatures even cooler than normal, perhaps into the middle of September!  I’d say our chance for hitting the century mark again this year are growing awfully slim. We’d have to see a major pattern adjustment and drier air to make that happen by that point.

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                To sum up, Harvey will continue to bring catastrophic flooding in Texas and parts of Louisiana while we see just a smattering of showers as it glides by to our east. We remain in a fairly dry, quiet pattern with any major heat sequestered to the West Coast. In just about a week, some really refreshing air will arrive. Along the Gulf Coast, a wetter than normal pattern likely holds on into September as shown below, which is the last thing anyone down there needs. We’ll hope and pray floodwaters can recede as quickly as possible for our friends to the south.

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