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.

Do you like surprises? I like surprises, so I am a fan of how this month turned out. WeatherNation, who very often gloms on to the Weather Service Forecast, found itself oscillating between the Weather Service, the Weather Channel and sometimes it’s own forecast, and managed to grab the Forecaster of the Month award for the month of July. Cagey strategy, and a big reward.