Major flooding has been occurring along portions of the Northern and Southern State Parkway on Long Island Friday afternoon, August 10, 2012. (Image from NYSDOT).
Along with the risk of damaging thunderstorm winds, there is an elevated threat of flash and urban flooding in the Northeast into Saturday.
Torrential downpours have and will continue to cause transportation delays from Virginia to Maine.
Multiple lines of slow-moving, repeating showers and thunderstorms will unload heavy rainfall on the region into Saturday.
The pattern has the potential to unload a general 1 to 2 inches with local amounts of 4 inches. While this may not seem so bad, a significant amount of this ran can fall in several hours or less.
Rainfall rates of an inch per hour can easily overwhelm storm drains causing water to flood streets and basements.
Small streams can rapid rise and overflow their bands.
The central Appalachians were slammed by torrential downpours Thursday night, and more downpours are on the way for the mountains and valleys into Friday evening.

According to Severe Weather Expert Henry Margusity, "During Friday midday, the storms were slamming areas from Philadelphia to New York City in response to an area of low pressure embedded within the shower and thunderstorm regime."
Mass transit, street and highway delays are likely.
"This feature will move on into Hartford, Boston and other locations in New England during the afternoon and evening hours Friday," Margusity added.
The showers and thunderstorms will slowly retreat toward the Atlantic Ocean over the weekend. However, downpours will still plague the I-95 corridor from Richmond to Portland, Maine, on Saturday. Even on Sunday, a downpour is possible on area beaches from the Outer Banks of North Carolina to Cape Cod and Down East Maine.
NOAA released its 2013 Atlantic Hurricane Season Forecast Thursday, predicting another active season.
This holiday weekend, a rare astronomical phenomenon will occur that will not be seen again until October 2015.
San Antonio is getting hit by heavy thunderstorms on Friday afternoon and evening.
A few days after a chilly storm departs the Northeast, warm weather will make a strong comeback in parts of the Midwest and the East later next week.
Severe weather and drenching downpours will affect parts of the Plains and Midwest over the Memorial Day Weekend.
"This pup was literally singing when he saw his family," Michelle Karolicki, relocation program manager of the Central Oklahoma Humane Society, said about a reunion that took place on Thursday.
| Extreme | Location | |
|---|---|---|
| High | N/A | |
| Low | N/A | |
| Precip | N/A |
Brownsville, TX (1998)
Just 0.04" of rain since April.
Knoxville, TN (1807)
Hail 10" in circumference hail; a tornado went
over the river, sucking fish out of the water.
Northeast (1877)
Inland snowstorm from New Jersey to New England;
4" of snow at Berkshire County, MA.
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