Update 7:20 p.m. EDT Thursday May 23, 2013 This blog is no longer live. It was last updated on June 1, 2012.
What to expect:
Accompanying the risk of thunderstorms with strong winds and large hail into Friday evening is the potential for a few tornadoes.
9:50 P.M.: Thunderstorm wind damage reports all across PA: Fulton, Blair, York, Clearfield, Mifflin, Potter and York Counties.
8:27 P.M.: Reports of tornadoes in Raleigh Terrace, VA, 1 mile northeast of Kecoughtan, VA and at BWI airport in Anne Arundel, MD.
Widespread damage to homes reported in Merrimac Shores, VA.
7:37 P.M.: Reports of thunderstorm wind damage across PA: Mobile home overturned and trees down in Clearfield County, wires down in Cambria County.
7:10 P.M.: Report of a funnel cloud south of Ashland in Hanover County, VA.
6:45 P.M.: Report of a funnel cloud E. of Centerville, Goochland County, VA.
6:38 P.M.: Flooding reported in Lancaster County, PA.
6:15 P.M.: Funnel cloud and several downed trees reported in Benson, Harford County, MD.
6:00 P.M.: Trees and wires down in Somerset, PA.
5:37 P.M.: Unconfirmed tornado reported Ligonier, PA. Reports of snapped trees, roofs off structures, and other structural damage.
5:27 P.M.: Multiple reports of a funnel cloud 500 to 1000' off the ground near US 340 & US 15 intersection in Frederick, MD.
5:23 P.M.: Preliminary report: Officer reported tornado on the ground just north of Highway 17, two miles north of Chesterfield in Pasquotank County, N.C. Tornado lifted after several minutes but rotation was still evident, the report reads.
5:19 P.M.: Tornado possibility in Central Prince William County, N. Virginia & Southern Fairfax County, Northern Virginia through 5:45 p.m.
5:00 P.M.: Tornado possible in Western Prince Georges County, Central Maryland through 5:15 PM
4:50 P.M.: Preliminary report: Funnel Cloud spotted 1 mile N of Shrewsbury, York County, PA at 4:26 PM
4:40 P.M.: Tornado possibility for S. Baltimore County, NW Anne Arundel County, MD & SE Howard County, MD. through 5 PM.
4:19 P.M.: New tornado producing storm south of DC moving toward Bryans Road.
3:53 P.M.: Preliminary report released: Funnel cloud spotted in Mackeys, N.C. at 3:29 P.M. Several trees down in Southampton County, VA.
3:43 P.M.: Training thunderstorms causing flash flooding Albermarle County, VA.
3:24 P.M.: Preliminary storm reports show a funnel cloud reported 3 miles southwest of Damascus in Montgomery County, MD. No damage reported.
2:30 P.M.: Doppler radar indicating multiple rotating thunderstorms, capable of producing tornadoes over Virginia and Maryland at this time.
1:59 P.M.: "The storm [southwest of] Charlottesville has 64 knots of rotation," Accuweather meteorologist Henry Margusity said. "That's very strong. That's almost hurricane wind speeds at 6,000 feet."
1:54 P.M.: The Storm Prediction Center issued a second tornado watch box covering eastern areas in Pennsylvania, Maryland, Virginia and North Carolina.
The Difference Between Tornado Watches and Warnings
01:29 P.M.: The Storm Prediction Center issued a huge tornado watch box for areas in Pennsylvania, West Virginia, Maryland, Virginia, and North Carolina that expires at 9 P.M.
01:14 P.M.: AccuWeather broadcaster Violeta Yas tweeted "Not expecting a tornado outbreak, but conditions very conducive for wind damage in some of those highly populated areas, especially 2pm-9pm." To be clear, tornadoes could develop today but it likely won't be a mega-outbreak.
01:06 P.M.: "The storms are just getting going," AccuWeather meteorologist Henry Margusity said. "In the next one to three hours we'll start to see something."
12:35 P.M.: Radar at 12:15 p.m. EDT indicated potentially damaging thunderstorms developing over central and northeastern North Carolina to southern Virginia.
12:30 P.M. : The Storm Prediction Center released an updated severe weather outlook for Friday.
08:00 A.M. : AccuWeather meteorologist Alex Sosnowski says "The prime threat area for tornadoes with this event will be bounded by the Pennsylvania Turnpike to the north, I-81 to the west, I-95 to the east and I-40 to the south."
Tornado Risk DC, Lancaster, Raleigh, Roanoke
Temperatures will remain in the 90s across the Metroplex through the Labor Day weekend.
More unsettled weather is coming to the Minneapolis area.
While Marie will stay well offshore from Los Angeles, it will continue to produce dangerous surf along many Southern California beaches through Thursday.
While Hurricane Cristobal will track east of the United States this week, it will spread rough surf along much of the Atlantic coast and will have some direct impact on Bermuda.
After a brief cooldown late this week, very warm and humid air will bounce back during the Labor Day weekend.
While the weather over much of the Atlantic and Pacific coasts will be free of rain this Labor Day weekend, a zone of unsettled weather will reach across part of the Central states.
Pennsylvania & New Jersey (1971)
Tropical Storm Doria caused severe floods in southeastern PA and NJ. Damage estimated at $138 million.
Colorado Springs, CO (1978)
Hail 6 inches deep.
Rochester, MN (1979)
2.73 inches of rain fell in 50 minutes making this the wettest August on record. (9.52 inches of rain so far this month). The heavy downpour flooded the streets of Rochester, stranding about 1,500 cars.