02 Arizona flash flooding
Why flash floods are so dangerous
01:06 - Source: CNN
CNN  — 

The city of New Orleans woke up to extensive flooding Monday morning. Storms that developed overnight and into the early morning hours have dumped widespread rainfall totals of 3 to 6 inches of rain across the Gulf Coast.

This amount of rain in a short period of time has led to flash flooding across the region and has hit the city of New Orleans hard.

Flooding inundated several streets and underpasses in the city so far during the morning after more than 6 inches of rain fell, according to radar estimates.

The rain – with reported rates of 3 to 4 inches per hour in some areas – also impacted downtown New Orleans, including parts of the French Quarter.

Observed rainfall since early Monday morning, highlighting rainfall estimates of up to 6 inches of rain.

The rain and thunderstorms will continue across southeastern Louisiana in the morning and are forecast to persist through the afternoon, according to the National Weather Service office in New Orleans.

A ‘considerable’ flash flood warning issued for Metro New Orleans remains in effect until 12 p.m. local time (1 p.m. ET). This type of warning is used in rare situations when flash flooding is unusually severe or urgent action is needed to protect lives and property.

The NWS also reported numerous roads between New Orleans and Slidell, LA became partially or completely impassable during the morning and the standing water will be very slow to drain.

Weather models project up to 6 to 11 inches of additional rainfall for the New Orleans metro area. “High-end, potentially catastrophic flash flooding could unfold if this were to occur in the urban locales,” says the NWS.

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The NWS also notes that models showed lots of rainfall since yesterday and it is important to communicate worst-case scenario situations.

More flooding is likely, especially along the south shore of Lake Pontchartrain, where storms are expected to dump excess rainfall over the same locations.

Flash flooding impacts 3 million people

Forecast rainfall through Monday evening

Flash flood watches are in effect for about 3 million people in Louisiana and Mississippi for this flooding potential, including New Orleans, Baton Rouge and Biloxi.

This part of the country has had a rainy and wet spring. Rainfall in New Orleans reached more than 5 inches above average in March and over 8 inches above average in April. So far this month, rain fell upwards of 2.03 inches higher than normal.

Flash flooding is also possible Monday across portions of Texas, Arkansas and Mississippi as the storms roll through. A few of these storms could be severe, with damaging winds as the main threat.

Storms should move offshore and toward the Gulf of Mexico Monday evening, with most rainfall activity diminishing Monday night.

CNN Meteorologists Monica Garrett and Brandon Miller contributed to this report.