We are approaching the end of August, and the peak of hurricane season is a little more than two weeks away, and we haven’t had a named feature since Tropical Storm Colin graced the Georgia coast at the beginning of July. The way it looks, we will make it until at least September until we have our “D” storm, given the current NHC outlook.

Each of those two yellow x’s represent a wave that ultimately could become a named tropical feature, but the NHC outlook suspects that formation chance is merely 20% through the next 5 days, which takes us to the end of the month with a day to spare. If these storms fail to materialize, and nothing else crops up in the intervening days, it would be the first time since 1997 that we went through August without a named storm in the Atlantic basin, and only the 2nd time since 1961. The fact that one of those x’s lies off the coast of Africa suggests that there is little time for another feature to arrive behind it, and a surprise is even less likely than usual.

The long range GFS model is pretty consistent with a tropical feature showing up at the beginning of September, and that wouldn’t really be a surprise. There is no causation of a quiet September simply because there is a quiet August. Colorado State hasn’t revised their predictions for the season yet. A quiet season in 1992 didn’t have a named storm until August — Hurricane Andrew. That 1961 season didn’t have any August storms, but did have two Category 5 hurricanes later in the season.

I haven’t found a season that hadn’t had a hurricane by September, though, and that would certainly be unusual, if not historic. We’ve also had the first season in 8 years without a named storm before the hurricane season officially starts on June 1st. It’s been a slow start, and it continues to remain slow for the coming days. We should appreciate that while it lasts.

The remnants of a weak tropical feature came ashore in Texas over the weekend, noted only in reference to how quiet the Tropics have been this season. This weak, nameless blob was about all that had troubled North America this summer so far. It gathered a lot more attention overnight into this morning by dumping torrents of rain on the Dallas metro, leading to flash flooding throughout the Big D and Fort Worth.

At least 2 inches of rain have fallen in broad swaths of North Texas and up to 8 were estimated in some spots, making city streets waterlogged and impassable in some places. Radar shows that more rain is coming, though fortunately, Fort Worth should be drying out.

Flash flooding is different than river flooding, in that the onset is much more rapid and isn’t necessarily confined to existing waterways. River flooding can be planned a bit better for evacuations and bracing for the impacts of rising rivers, but flash flooding, like the rain in Dallas, can happen with a lot of rain coming in just a few hours, and is not as easy to anticipate.

There are two particular amplifiers of flash flooding. One of them is the increasingly paved surfaces we find in urban areas. Water pools, unable to drain from roadways, and can cause vehicles to hydroplane or even float. If the water is moving, for example if a nearby waterway has spilled out of its banks, or if the inundated roadway slopes, just a few inches of water are enough to move a vehicle. If water is deep enough, it can cause engines to stall.

The worst case scenario for flash flooding is usually found in hilly or mountainous terrain, such as what happened in eastern Kentucky this summer. Rainwater is channeled into valleys, causing existing rivers and creeks to rise quickly, and sweep away mud, trees and edifices in the water’s path downward. Unlike normal river flooding, which arises from water coming downstream after snow melts or a long, wet season, flash flooding happens in an instant as water flows downhill. Some of the deadliest flash flooding instances in the US occurred in Oregon and Colorado.

Heavier rains are a response to slow moving storms with higher dew points, and are possible even when severe weather hasn’t occurred. It’s always important to stay aware of your surroundings, and not pass through standing water, because you never know what lies beneath.

Late August usually brings out the posts about the coming tropical season and the increasing threat. The peak of the tropical season is less than a month out, and while the NHC continues to forecast a busier than normal season, the Atlantic remains quiet. So we turn our attention to the rest of August in the continental US.

The 8-14 day outlook from the CPC has much of the country in below normal temperatures. This is accompanied by above normal precipitation in the same regions, and as a reminder that summer is still around, a heat wave on the west coast.

Oceans continue to warm through the summer as the sun angle stays strong, which is why late August and September are busiest in the Atlantic, but over large landmasses, air masses are more vulnerable to changes. While the sun is warming the oceans, the angle is reducing, and the jet starts sinking south. There is more variability in the weather pattern, and when there is variability, there is the threat for thunderstorms.

There might be some instinct to believe that the extremely divergent temperatures relative to normal found on the coasts versus that in the middle of the country. Looking at the upper level pattern, though, this doesn’t quite seem likely. Typically weak summertime flow is going to continue until late in this outlook period, which means these cooler temperatures will probably be a result of moisture and cloud cover thanks to an array of surface perturbations.

Shorter waved features are more spurious, and is why there is less confidence in the below normal temperature field than with the warmer regions, which are a result of strong jet stream ridges in the forecast. There isn’t the full level cold air mass in the middle of country to provide the clash of airmass you need for big severe outbreaks. There will certainly be some thunder embedded within all the rain coming Middle America’s way, but not high risk days from the Storm Prediction Center.

Generally, there is usually a late year severe weather peak at the beginning of fall, as cold air really starts to come back to town. Unlike the spring severe season, cold air is denser and tends to completely supplant warm air. Cold air is reinforced, and warm air has a tougher time coming back, so the severe season is shorter than spring, where warm air keeps trying to bubble up.

Like the tropical season this year, we shouldn’t read to much into this quiet October. The hurricane season, like the fall severe season could still get very interesting very quickly.