Devastating Hurricane Harvey, unprecedented in its rainfall, could be a slight negative for U.S. growth in the third quarter, but economists say it may ultimately provide a tiny boost to the national economy because of the rebuilding in the Houston area.

Goldman Sachs economists estimate a very preliminary impact of the storm to be $30 billion in property damages, making it the ninth largest since World War II in terms of domestic property damage. Goldman economists say, in a note, the storm could take 0.2 points off of growth in third quarter because of the impact to the energy sector.

JPMorgan chief U.S. economist Michael Feroli said JPMorgan analysts estimate physical damage from Harvey at between $10 to $20 billion, putting it in the top 10 costliest storms but still well below the record $159 billion damage from Katrina. He said it could add about 0.1 percent to growth, but so far he is not changing his forecast for 2.3 percent third quarter growth and 1.8 percent fourth quarter growth.

"Usually what we see is transitory. Usually, you see a little bit of weakness as interruption to businesses occur. Houston is not a small footprint. You can see a disruption to business, then you tend to see a spurt," said Diane Swonk, CEO of DS Economics. "This is a different kind of area than Katrina. It has airport hubs and things like that."

Growth is tracking at just around 3 percent in the third quarter. Swonk estimates that Harvey could add a few tenths of a percent of growth to the fourth quarter, which she sees at 2.4 percent.

President Donald Trump Monday said he expects "very rapid action" on Harvey relief funding. The president was expected to visit Texas on Tuesday.

Feroli , in a note, points out that the economy in the affected region could suffer while the national economy benefits. He noted that after Sandy in 2012, New York's economy suffered but the national economy did not. The same happened with the Louisiana economy after Katrina in 2005.

The Goldman economists said the overall impact of the hurricane on second-half growth is uncertain because the negative effects will likely be offset by an increase in business investment and construction activity.

There are also some ways the storm could spark a rise in inflation, which has been surprisingly weak this year.

In Houston's case, the storm's impact on the refining sector and gasoline prices could spark inflation, said Swonk. Inflation slowed down this year and is a point of concern to the Federal Reserve, which would like to see more before it raises interest rates later in the year.

The obvious way Harvey could affect inflation is through gasoline prices at the pump, which are already rising just because Houston and the surrounding area have been forced to shut down refining production.

"Gasoline prices are going to pick up. We won't know how much until waters recede. We know that production is currently offline," said Swonk.

Patrick Dehaan, Senior Petroleum Analyst at GasBuddy, estimates a 25 to 30 cent per gallon jump in prices at the pump by Labor Day weekend.

But that number could rise if any refineries or pipelines look to be out of commission for more than a few days. The refining sector remains a wild card, and could be a drag on the consumer and economy if there's any significant damage that would send prices spiking for any length of time.

"Our commodities team estimates that Harvey has already shut down over 16.5 percent of US refining capacity, and we estimate that disruptions in the energy sector could directly reduce Q3 GDP growth by as much as 0.2pp," wrote the Goldman economists.

Another reason Houston could generate a little inflation is because it's already facing a shortage of construction workers, and if the massive rebuilding effort attracts workers from other states, that shortage could go national, Swonk said. The competition for workers could lead to higher wages.

Another temporary blip in inflation and a boost in consumption could come from car sales. Car prices, for new and used models, have been falling but an expected a surge in demand to replace vehicles lost in flood waters could result in an increase in prices, particularly for used cars.

There could also be a pickup in building materials sales and possibly prices, with lumber already rising because of the new U.S. tariffs on Canadian soft lumber, Swonk said. However, any pickup in inflation could also be offset by a decline in inflation, due to the Amazon and Whole Foods merger. Amazon already cut prices at the grocery chain on its first day of ownership.

Feroli said the Houston metropolitan area accounted for about $500 billion of output in 2015.

"This level of output was close to the total output of Norway as a whole and made the Houston area the fourth largest metropolitan area in terms of output for that year. But we should remember that US GDP was $18 [trillion] that year, with less than 3 percent of that total," Feroli said in a report.

The hurricane's impact could show up in other data, like September's employment report. Economists say there could be fewer workers making it to work and that could show up in the monthly report, when its released in early October.

Feroli said there could also be a jump in jobless claims from Texas a week or two after the storm because Harvey could certainly put people out of work and then prevent them from filing a claim immediately.